Mybatis学习笔记

之前持久层框架一直用的是ibatis，现在开始使用Mybatis注解的形式。总体感觉使用起来差别不是太大，但是为了更快的进行项目开发，还是稍微熟悉一下Mybatis框架。

MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为MyBatis 。2013年11月迁移到Github。其它的理论性的东西一搜一大把，所以我还是更加倾向于实践。

1、首先新建一个maven快速启动项目。配置pom.xml，下载需要的jar包。

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.blog.core</groupId>  <artifactId>com.blog.core</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>com.blog.core</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </properties>  <dependencies>    <dependency>      <groupId>junit</groupId>      <artifactId>junit</artifactId>      <version>3.8.1</version>      <scope>test</scope>    </dependency>     <dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-core</artifactId>    <version>3.2.2.RELEASE</version></dependency> <dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-context</artifactId>    <version>3.2.2.RELEASE</version></dependency> <dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-beans</artifactId>    <version>3.2.2.RELEASE</version></dependency>      <dependency>           <groupId>log4j</groupId>           <artifactId>log4j</artifactId>           <version>1.2.16</version>        </dependency>            <dependency>    <groupId>org.mybatis</groupId>    <artifactId>mybatis</artifactId>   <version>3.1.1</version>   </dependency>  <dependency>    <groupId>mysql</groupId>    <artifactId>mysql-connector-java</artifactId>    <version>5.1.24</version></dependency><dependency>    <groupId>org.mybatis</groupId>    <artifactId>mybatis-spring</artifactId>    <version>1.2.2</version></dependency><dependency>    <groupId>com.alibaba</groupId>    <artifactId>druid</artifactId>    <version>1.0.13</version></dependency>    </dependencies>   </project>

2、配置applicationContext.xml文件：

<?xml version="1.0" encoding="GBK"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans  http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/aop  http://www.springframework.org/schema/aop/spring-aop-3.2.xsd">    <!--  <import resource="/config/dubbo-provider.xml"/> --> <!-- properties加载 -->    <bean id="configProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">        <property name="locations">            <list>                <value>classpath*:*.properties</value>            </list>        </property>    </bean>    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">        <property name="ignoreResourceNotFound" value="false" />        <property name="properties" ref="configProperties" />    </bean>      <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"          destroy-method="close">          <!-- 基本属性 url、user、password -->          <property name="url" value="${url}" />          <property name="username" value="${username}" />          <property name="password" value="${password}" />          <property name="driverClassName" value="${driverClassName}" />  <!-- 配置初始化大小、最小、最大 --> <property name="initialSize" value="${initialSize}" /><property name="minIdle" value="${minIdle}" />        <property name="maxActive" value="${maxActive}" />        <!-- 配置获取连接等待超时的时间 -->         <property name="maxWait" value="${maxWait}" />     <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->         <property name="timeBetweenEvictionRunsMillis" value="${timeBetweenEvictionRunsMillis}" />           <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->          <property name="minEvictableIdleTimeMillis" value="${minEvictableIdleTimeMillis}" />            <property name="validationQuery" value="${validationQuery}" />          <property name="testWhileIdle" value="${testWhileIdle}" />          <property name="testOnBorrow" value="${testOnBorrow}" />          <property name="testOnReturn" value="${testOnReturn}" />          <property name="maxOpenPreparedStatements"  value="${maxOpenPreparedStatements}" />         <!-- 打开removeAbandoned功能 -->         <property name="removeAbandoned" value="${removeAbandoned}" />         <!-- 1800秒，也就是30分钟 -->            <property name="removeAbandonedTimeout" value="${removeAbandonedTimeout}" />         <!-- 关闭abanded连接时输出错误日志 -->        <property name="logAbandoned" value="${logAbandoned}" />         <!-- 配置监控统计拦截的filters，去掉后监控界面sql无法统计 -->           <property name="filters" value="${filters}" />       </bean>          <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">         <property name="dataSource" ref="dataSource" />         <property name="configLocation" value="mybatis-config.xml"/>      </bean>   <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">      <constructor-arg index="0" ref="sqlSessionFactory" />     </bean>        </beans>

注：数据库连接池用的是阿里的Druid，这跟DBCP，C3P0这些数据库连接池的配置总体差不多。

3、配置mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>  <!DOCTYPE configuration    PUBLIC "-//mybatis.org//DTD Config 3.0//EN"    "http://mybatis.org/dtd/mybatis-3-config.dtd">  <configuration>      <!-- 对事务的管理和连接池的配置 -->     <!--  <environments default="development">          <environment id="development">              <transactionManager type="JDBC" />              <dataSource type="POOLED">                  <property name="driver" value="oracle.jdbc.driver.OracleDriver" />                  <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl" />                  <property name="username" value="ibatis" />                  <property name="password" value="ibatis" />              </dataSource>          </environment>      </environments>  -->           <!-- mapping 文件路径配置 -->      <mappers>        <!-- 因为采用注解，所以直接指定包，自动扫描 -->        <package name="com.blog.mapper"/>    </mappers>  </configuration>

4、创建数据库连接常量定义jdbc.properties

url:jdbc:mysql://localhost:3306/blog_newsdriverClassName:com.mysql.jdbc.Driverusername:rootpassword:rootfilters:statmaxActive:20initialSize:1maxWait:60000minIdle:10#maxIdle:15timeBetweenEvictionRunsMillis:60000minEvictableIdleTimeMillis:300000validationQuery:SELECT 'x'testWhileIdle:truetestOnBorrow:falsetestOnReturn:false#poolPreparedStatements:truemaxOpenPreparedStatements:20#对于长时间不使用的连接强制关闭removeAbandoned:true#超过30分钟开始关闭空闲连接removeAbandonedTimeout:1800#将当前关闭动作记录到日志logAbandoned:true

5、日志配置

log4j.rootLogger=INFO,A1    log4j.appender.A1=org.apache.log4j.ConsoleAppender  log4j.appender.A1.layout=org.apache.log4j.PatternLayout  log4j.appender.A1.layout.ConversionPattern=%-5p %d{yyyy-MM-dd HH:mm:ss,SSS} [message] %m%n      log4j.appender.A2=org.apache.log4j.FileAppender  log4j.appender.A2.File=D:/log.log  log4j.appender.A2.layout=org.apache.log4j.PatternLayout  log4j.appender.A2.layout.ConversionPattern=%-5p %d{yyyy-MM-dd HH:mm:ss,SSS} [message] %m%n 

6、创建Mybatis的Mapper类UserMapper.java

package com.blog.mapper;import java.util.Map;import org.apache.ibatis.annotations.InsertProvider;import org.apache.ibatis.annotations.Param;import org.apache.ibatis.annotations.SelectProvider;import com.blog.model.User;import com.blog.sqlprovider.UserSqlProvider;public interface UserMapper {@InsertProvider(type=UserSqlProvider.class,method="addUser")public int addUser(@Param("params") Map<String,Object> params);@SelectProvider(type=UserSqlProvider.class,method="queryUser")public User queryUsreByUserNameAndPwd(@Param("params") Map<String, Object> params);}

7、创建Mybatis的sql映射类UserSqlProvider.java：

package com.blog.sqlprovider;import java.util.Map;public class UserSqlProvider {public String addUser(Map<String,Object> params){StringBuilder sb=new StringBuilder("");sb.append("INSERT INTO user_main(userId,password)");sb.append(" VALUES(#{params.userId},#{params.password})");return sb.toString();}public String queryUser(Map<String,Object> params){StringBuilder sb=new StringBuilder("");sb.append("SELECT * FROM user_main ");sb.append(" where userId=#{params.userId} and password=#{params.password}");return sb.toString();}}

8、另外需要用到的实体类User.java

package com.blog.model;public class User {private int id;private String userId;private String password;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUserId() {return userId;}public void setUserId(String userId) {this.userId = userId;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

项目结构大致如下图：

Main测试类如下：

package com.blog.startup;import java.io.IOException;import java.util.HashMap;import java.util.Map;import org.mybatis.spring.SqlSessionTemplate;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.blog.mapper.UserMapper;import com.blog.model.User;public class Main {public static void main(String[] args) throws IOException {ClassPathXmlApplicationContext applicationContext=new ClassPathXmlApplicationContext("config/applicationContext.xml");SqlSessionTemplate sessionTemplate=(SqlSessionTemplate)applicationContext.getBean("sqlSessionTemplate");UserMapper userMapper= sessionTemplate.getMapper(UserMapper.class);Map<String,Object> param=new HashMap<String, Object>();param.put("userId", "10000001");param.put("password", "admin123456");//userMapper.addUser(param);User user=(User)userMapper.queryUsreByUserNameAndPwd(param);System.out.println("userId:"+user.getId()+",password:"+user.getPassword());}}

数据库建表sql如下：

CREATE TABLE `user_main` (  `id` int(11) NOT NULL auto_increment COMMENT '主键Id',  `userId` varchar(12) NOT NULL COMMENT '用户Id',  `password` varchar(64) NOT NULL,  PRIMARY KEY  (`id`),  UNIQUE KEY `unique_index_uerId` USING BTREE (`userId`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;