MyBatis学习（二）--走进MyBatis的世界

来源：互联网发布：ubuntu安装pycharm 编辑：程序博客网时间：2024/06/01 13:23

　　mybatis是个持久层的框架，用来执行数据库操作的，无外乎增删改查，上一节对mybatis有了宏观上的了解后，这一篇博客主要通过一个小示例来入门mybatis，先看一下要写的示例需求：

根据用户id查询用户信息
根据用户名称模糊查询用户信息
添加用户、删除用户、更新用户

　　其实也就是增删改查，掌握这些，基本上就掌握了mybatis的基本操作了，下面一个个模块来完成。

1. mybatis环境准备

　　毫无疑问，砍柴得有把刀才行，环境的搭建是开发中必需的一个流程，mybatis的环境我分成以下几个部分来总结：

1.1 mybatis运行环境

　　mybatis运行环境主要是指mybatis的jar包，mybatis已经将它的各个版本托管到github上了，大家可以去github上下载，（如果觉得不方便）也可以去CSDN下载频道下载，我已经上传上去了，我用的是mybatis-3.3.0版本，下载地址==>传送门。
　　从mybatis的jar包中就可以看出，mybatis和hibernate有着强烈的对比，mybatis的jar包很简洁，不像hibernate有很多jar包，mybatis的jar包包括一个核心包和几个依赖包，我们全部导入到工程中即可。然后就是mysql的驱动包，也要导入到工程中。下面看一下总共需要导入的jar包：

1.2 log4j配置文件

　　从上面的jar包中可以看出，mybatis的依赖包中有很多日志包，既然mybatis依赖log4j，那我们首先要建立一个log4j.properties文件，这个可以在官方的文件中拷贝下，如下：

<code class="language-properties hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Global logging configuration</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># developer-->DEBUG  productor-->INFO or ERROR</span>log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootLogger</span>=DEBUG, stdout<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># MyBatis logging configuration...</span>log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.mybatis</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.example</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.BlogMapper</span>=TRACE<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Console output...</span>log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span>=org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.log</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ConsoleAppender</span>log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span>=org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.log</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.PatternLayout</span>log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ConversionPattern</span>=%<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">5</span>p [%t] - %m%n</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

　　在开发环境下日志级别要设置成DEBUG，产品模式下可以设置成INFO或者ERROR

1.3 全局配置文件

　　mybatis需要配置一个全局配置文件SqlMapConfig.xml，这个文件是用来配置mybatis的运行环境，即数据源、事务等。我们也可以从官方的例子中拷贝一份，然后做一下修改：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="UTF-8" ?></span><span class="hljs-doctype" style="color: rgb(102, 0, 102); box-sizing: border-box;"><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">configuration</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 和Spring整合后environment配置都会被干掉 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">environments</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">default</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"development"</span>></span>        <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">environment</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"development"</span>></span>            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 使用jdbc事务管理，目前由mybatis来管理 --></span>            <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">transactionManager</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"JDBC"</span> /></span>            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 数据库连接池，目前由mybatis来管理 --></span>            <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dataSource</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"POOLED"</span>></span>                <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">property</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"driver"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">value</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"com.mysql.jdbc.Driver"</span> /></span>                <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">property</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"url"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">value</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"jdbc:mysql://localhost:3306/mybatis"</span> /></span>                <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">property</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"username"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">value</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"root"</span> /></span>                <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">property</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"password"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">value</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"root"</span> /></span>            <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dataSource</span>></span>        <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">environment</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">environments</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mappers</span>></span>        <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">resource</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sqlmap/User.xml"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mappers</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">configuration</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

　　以上这些环境配置（<environments>标签中的内容在以后和Spring整合后，都会交给Spring来管理，现在暂时交给 mybatis来管理）中，修改成自己数据库相对应的情况即可，<mapper>标签用来配置映射文件的，这些映射文件是针对不同的pojo的，这个示例中只操作一个User对象，所以只有一个配置文件，在sqlmap目录下的User.xml，在下文中可以看到。最后来看一下整个环境的结构：

　　接下来就开始开发示例程序了。

2. 程序的编写

　　首先我们得有一个pojo，在mybatis.po包中新建一个User.java类：

　对应数据库的建表语句：

<code class="language-sql hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">use mybatis<span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">drop</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">table</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">exists</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">user</span>;</span><span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">create</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">table</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">user</span>(    id <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">primary</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">key</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">not</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span> auto_increment,    username <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">varchar</span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">40</span>),    birthday <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">date</span>,    sex <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>),    address <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">varchar</span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">255</span>));</span><span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">insert</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">into</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">user</span>(username,birthday,sex,address) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">values</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"张三1"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1990-09-19"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"男"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"同济大学"</span>);</span><span class="hljs-operator" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">insert</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">into</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">user</span>(username,birthday,sex,address) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">values</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"张三2"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1990-09-19"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"男"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"同济大学"</span>);</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*自己多加几个*/</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

　　下面开始写代码，完成示例程序。

2.1 根据用户id查询用户信息

　　首先得创建配置文件User.xml，并在配置文件中创建sql语句，如下：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="UTF-8" ?></span><span class="hljs-doctype" style="color: rgb(102, 0, 102); box-sizing: border-box;"><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"></span> <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">namespace</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"test"</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 需求：通过id查询用户 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">select</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"findUserById"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">parameterType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"int"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">resultType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"mybatis.po.User"</span>></span>        select * from user where id = #{id}    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">select</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

　　来简单解释下该配置文件中一些参数的作用：

<select>标签：用于执行数据库查询的，所有关于查询的都使用该标签。
id属性：标识映射文件中的sql，将sql语句封装到mappedStatement对象中，即statement的id，下面执行数据库的时候需要用到这个id。
#{}：表示一个占位符，用来接收输入参数的。
#{id}：id标识接收输入的参数，参数名称就是id，如果输入参数是简单类型，那么#{}中的参数名可以任意，可以value或者其他名称。
parameterType：指定输入参数的类型，这个要和数据库中的保持一致。
resultType：指定输出结果的类型，即查询结果所映射的java对象。

　　有了User.xml配置文件后，需要在全局配置文件SqlMapConfig.xml中添加这个映射，上面已经添加过了，即：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mappers</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">resource</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sqlmap/User.xml"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mappers</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

　　接下来就是写测试类了：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MybatisFirst</span> {</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//因为接下来的测试代码中，获取sqlSession这部分都相同，所以抽取成一个方法</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> SqlSession <span class="hljs-title" style="box-sizing: border-box;">getSession</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        String resource = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"SqlMapConfig.xml"</span>; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//mybatis配置文件</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//得到配置文件的流</span>        InputStream inputStream = Resources.getResourceAsStream(resource);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//创建会话工厂SqlSessionFactory,要传入mybaits的配置文件的流</span>        SqlSessionFactory sqlSessionFactory = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> SqlSessionFactoryBuilder().build(inputStream);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//通过工厂得到SqlSession</span>        SqlSession sqlSession = sqlSessionFactory.openSession();        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> sqlSession;    }    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//根据id查询用户的信息，得到一条记录的结果</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Test</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">findUserById</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        SqlSession sqlSession = getSession(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//调用上面的方法获取sqlSession</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//通过SqlSession操作数据库</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//第一个参数：映射文件中statement的id，= namespace + statement的id</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//第二个参数：指定和映射文件中所匹配的parameterType类型的参数</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//selectOne表示查询出一条记录进行映射</span>        User user = sqlSession.selectOne(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"test.findUserById"</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);        System.out.println(user);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//释放资源，最好放在finally中，这里只是测试程序，就不弄了</span>        sqlSession.close();    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li></ul>

　　从java程序中可以看出，这个流程很明确，就是上一节我画的那个mybatis的流程图，而且mybatis有个特点，就是要执行什么语句，都写在配置文件中，需要传入或者输出什么参数类型也写在配置文件中，在java中只要对应那个配置传入我们想要的参数或者接受输出参数即可，很方便。

2.2 根据用户名称模糊查询用户信息

　　有了上面的过程，接下来就比较简单了，使用mybatis开发，流程都一样，先在User.xml中添加配置：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">namespace</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"test"</span>></span>       <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 省略其他 --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 根据用户名称模糊查询用户信息，可能返回多条 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">select</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"findUserByName"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">parameterType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"java.lang.String"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">resultType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"mybatis.po.User"</span>></span>        select * from user where username like '%${value}%'    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">select</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

　　来解释下部分参数的作用：

resultType：这里虽然是查询多条记录，但是resultType指定的就是单条记录所映射的java对象类型。
${}：表示拼接sql串，将接收到的参数的内容不加任何的修饰拼接在sql中,${}中只能使用value，但是使用${}来拼接sql，可能会引起sql注入，所以不建议使用这种方法。

　　这里使用${}来拼接sql是为了后面java程序中直接输入方便（比如我模糊查询“张三”，就不用输入“%张三%”了），但是有sql注入的隐患。如果安全一点，还是使用#{}来接收参数，不过此时的话，java程序中输入参数就得是“%张三%”了。
　　下面看下java程序：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MybatisFirst</span> {</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//省略不相关代码</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//根据用户名称模糊查询用户列表</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Test</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">findUserByName</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        SqlSession sqlSession = getSession();        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//selectList表示查询出一个列表（多条记录）进行映射</span>        List<User> list = sqlSession.selectList(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"test.findUserByName"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"张三"</span>);        System.out.println(list);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//释放资源，最好放在finally中，这里只是测试程序，就不弄了</span>        sqlSession.close();    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li></ul>

　　处理流程和上面一模一样，不在赘述。

2.3 添加用户

　　首先完成添加用户的配置文件：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">namespace</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"test"</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 省略不相关配置 --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 添加用户 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">insert</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"insertUser"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">parameterType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"mybatis.po.User"</span>></span>        insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 将插入数据的主键返回，返回到user对象中 --></span>        <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">selectKey</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">keyProperty</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"id"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">order</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"AFTER"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">resultType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"java.lang.Integer"</span>></span>            select last_insert_id()        <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">selectKey</span>></span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!--         <selectKey keyProperty="id" order="BEFORE" resultType="java.lang.String">            select uuid()        </selectKey>         --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">insert</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

　　下面解释下部分属性的作用：

<insert>标签：用于执行数据库查询的，所有关于查询的都使用该标签。
parameterType：要传入一个具体的pojo（包括用户信息）
#{}中指定pojo的属性名，接收到pojo对象的属性值，mybatis通过OGNL获取对象的属性值。
<selectKey>标签：用来返回插入数据的主键的，实际中如果有获得主键的需要就可以使用它。
select last_insert_id()：是sql函数，表示得到刚刚insert进去记录的主键值，只适用于自增主键。
keyProperty：表示将查询到主键值设置到上面parameterType指定的对象的哪个属性。
order：表示select last_insert_id()的执行顺序，是相对于insert语句来说的。
resultType：表示select last_insert_id()的结果类型。

　　下面看下java代码：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MybatisFirst</span> {</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//省略不相关代码</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//添加用户信息</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Test</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">insertUser</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        SqlSession sqlSession = getSession();        User user = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> User(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"倪升武"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Date(), <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"男"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"同济大学"</span>);        sqlSession.insert(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"test.insertUser"</span>, user); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//添加一项</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//提交事务</span>        sqlSession.commit();        System.out.println(user.getId()); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获取刚刚添加的id</span>        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//释放资源，最好放在finally中，这里只是测试程序，就不弄了</span>        sqlSession.close();    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

2.4 更新用户和删除用户

　　接下来都比较简单了，基本参数的使用在上面都有涉及，我放在一起写了：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">namespace</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"test"</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 省略不相关配置 --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 删除用户 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">delete</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"deleteUser"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">parameterType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"java.lang.Integer"</span>></span>        delete from user where id=#{id}    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">delete</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- 更新用户 --></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">update</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"updateUser"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">parameterType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"mybatis.po.User"</span>></span>        update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">update</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mapper</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

　　下面看一下java代码：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MybatisFirst</span> {</span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//删除用户信息</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Test</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">deleteUser</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        SqlSession sqlSession = getSession();        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//传入id，删除用户</span>        sqlSession.delete(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"test.deleteUser"</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">16</span>);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//提交事务</span>        sqlSession.commit();        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//释放资源，最好放在finally中，这里只是测试程序，就不弄了</span>        sqlSession.close();    }    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//更新用户信息</span>    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Test</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">updateUser</span>() <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException {        SqlSession sqlSession = getSession();        User user = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> User(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"倪升武"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Date(), <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"男"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"同济大学"</span>);        user.setId(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">9</span>);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//更新用户</span>        sqlSession.update(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"test.updateUser"</span>, user);        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//提交事务</span>        sqlSession.commit();        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//释放资源，最好放在finally中，这里只是测试程序，就不弄了</span>        sqlSession.close();    }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li></ul>

　　好了，到这里mybatis的入门程序就写完了，从上面的程序来看，mybatis的基本操作还是挺简便的。主要要搞清楚mybatis的一个执行流程就比较好理解了。入门就总结这么多吧，希望这篇博文能代领mybatis的初学者走进mybatis的世界，包括我~~

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