【MyBatis】MyBatis Tomcat JNDI原理及源码分析

来源：互联网发布：日本电视节目直播软件编辑：程序博客网时间：2024/04/27 15:42

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一 Tomcat JNDI
1. jar包导入
2. 配置文件comtextxml
3. API代码示例
二MyBatis JNDI源码分析
1. 源码剖析
2. 代码范例

原文链接：http://blog.csdn.net/reliveit/article/details/45136297

一、 Tomcat JNDI

JNDI(java nameing and drectory interface)，是一组在Java应用中访问命名和服务的API，所谓命名服务，即将对象和名称联系起来，使得可以通过名称访问并获取对象。
简单原理介绍：点击访问

tomcat已经集成该服务（内置并默认使用DBCP连接池），简单来说就是键值对的mapping，而且在tomcat服务器启动的首页configuration中就已经有完成的示例代码。要想使用tomcat的JNDI服务，只需要导入相关的jar包，建立所需的配置文件，采用JDK的命名服务API根据配置名称即可获得相应的服务。每个步骤的详细解释以及范例如下文所述。

1. jar包导入

tomcat内置了DBCP并默认使用该连接池，在tomcat的lib包中已经DBCP的两个jar包，因此不需要导入，如果使用其他连接池技术，则需要重新拷贝连接池的jar包。拷贝数据库驱动包到tomcat lib目录下，完成jar包的导入。

细节：将所需jar包直接拷贝到tomcat的lib目录中，而不是在应用中build path导入jar包。这是因为JNDI的原理类似于windows的注册表，通过配置文件（context.xml：下节详细介绍）在tomcat启动的时候就告诉tomcat在其命名服务目录下对应着配置文件中的服务名字创建服务应用。这是tomcat对外提供的一个整体服务，而不是单独对某一个应用提供的服务。

2. 配置文件：comtext.xml

在META-INF目录下建立context.xml配置文件，在文件中需要配置资源名字name和资源类型type，建立文件的目的就是告诉服务器根据服务名字创建相应的服务应用。

如下示例（DBCP），服务名称是“jdbc/mybatis-jndi”，对应的服务类型是“javax.sql.DataSource”，即通过Tomcat提供的JNDI服务，根据name=“jdbc/mybatis-jndi”可以获取到type=“javax.sql.DataSource”的服务，至于type中还需要配置什么东西，则根据实际的type类型来进行配置即可。

<code class="hljs xml 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-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-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-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);">Context</span>></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- maxActive: Maximum number of database connections in pool. Make sure         you configure your mysqld max_connections large enough to handle all of your         db connections. Set to -1 for no limit. --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- maxIdle: Maximum number of idle database connections to retain in pool.         Set to -1 for no limit. See also the DBCP documentation on this and the minEvictableIdleTimeMillis         configuration parameter. --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- maxWait: Maximum time to wait for a database connection to become available         in ms, in this example 10 seconds. An Exception is thrown if this timeout         is exceeded. Set to -1 to wait indefinitely. --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- username and password: MySQL username and password for database connections --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- driverClassName: Class name for the old mm.mysql JDBC driver is org.gjt.mm.mysql.Driver         - we recommend using Connector/J though. Class name for the official MySQL         Connector/J driver is com.mysql.jdbc.Driver. --></span>    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;"><!-- url: The JDBC connection url for connecting to your MySQL database. --></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);">Resource</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);">"jdbc/mybatis-jndi"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">auth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"Container"</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);">"javax.sql.DataSource"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxActive</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"100"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxIdle</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"30"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxWait</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10000"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">username</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"root"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">password</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"51NByes!"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">driverClassName</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"com.mysql.jdbc.Driver"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">url</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"jdbc:mysql://localhost:3306/javadb"</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);">Context</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></ul>

3. API代码示例

通过JDK提供的命名服务API，可以通过name获取type服务，示例代码如下，其中tomcat将所有JNDI对应服务注册在/com/env目录之下（写法固定，除非不同版本的tomcat有不同的实现），因此应用想要获取服务，则需要先知道tomcat的jndi都提供了哪些服务，在根据某一个服务的name来获取具体的服务，而这个name对应着上一节中context.xml中配置的name。

<code class="hljs vhdl 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-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">Context</span> initContext = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> InitialContext();<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">Context</span> envContext = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">Context</span>) initContext.lookup(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"java:/comp/env"</span>);DataSource ds = (DataSource) envContext.lookup(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"jdbc/mybatis-jndi"</span>);Connection conn = ds.getConnection();</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></ul>

这里写图片描述

总结使用tomcat的JNDI服务需要以下三个步骤
1. 拷贝jar包到tomcat的lib目录中
2. 在应用的META-INF目录中建立context.xml配置文件，将KV的服务注册到tomcat的”java:/comp/env”目录下
3. 通过JDK naming API获取服务

二、MyBatis JNDI源码分析

MyBatis的dataSource类型有三种，其中JNDI的实现和tomcat JNDI一模一样，只是MyBatis的JNDI工厂（org.apache.ibatis.datasource.jndi.JndiDataSourceFactory）已经帮我们实现了第三步”通过API获取datasource“，但是还需要我们自己进行第一步导入jar包和第二步context.xml的配置。

细节：
1. 在进行context.xml配置的时候，其中服务名称是可变的，需要通过配置文件注入到MyBatis的JNDI工厂中；
2. 因为不同服务器的JNDI目录不一样，因此在context.xml中配置的时候也许要注入到MyBatis的JNDI工厂中；

1. 源码剖析

<code class="hljs java 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-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> cn.wxy.analysis;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.Map.Entry;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.Properties;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.naming.Context;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.naming.InitialContext;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.naming.NamingException;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> javax.sql.DataSource;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.apache.ibatis.datasource.DataSourceException;<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.apache.ibatis.datasource.DataSourceFactory;<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Mybatis JNDI源码剖析 *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span> Administrator */</span><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);">JndiDataSourceFactory</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">DataSourceFactory</span> {</span>    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * initial_context: 服务器的JNDI目录，不同的服务器该值不同，因此需要在mybatis-config的配置文件中传入该值     * data_source：对应着META-INF/context.xml中注册的服务名称（name属性值），即键值对中的键值     */</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;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String INITIAL_CONTEXT = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"initial_context"</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;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String DATA_SOURCE = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"data_source"</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;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String ENV_PREFIX = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"env."</span>;    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> DataSource dataSource;    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 该方法在初始化Mybatis的时候被调用，会将mybatis-config.xml中配置的属性注入进来     * 主要注入的是initial_context和data_source的值     */</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;">setProperties</span>(Properties properties) {        <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**         * 参照tomcat直接获取JNDI服务         * -------------------------         * 第一步：Context initContext = new InitialContext();         * 第二步：Context envContext = (Context) initContext.lookup("java:/comp/env");         * 第三步：DataSource ds = (DataSource) envContext.lookup("jdbc/mybatis-jndi");         */</span>        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//第一步：声明JAVA命名和目录接口的上下文类</span>            InitialContext initCtx = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;            Properties env = getEnvProperties(properties);            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (env == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {                initCtx = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> InitialContext();            } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {                initCtx = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> InitialContext(env);            }            <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**             * mybatis-config.xml中有两种方式可以进行JNDI数据源的配置             * 1. 第一种方式需要配置initial_context和data_source的值，本例中             *      initial_context="java:/comp/env"             *      data_source="jdbc/mybatis-jndi"             * 2. 第二种方式只需要配置data_source的值             *      data_source="java:/comp/env/jdbc/mybatis-jndi"             *              * 结论：其实是一样的，请结合context.xml配置文件内容查看此处             */</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (properties.containsKey(INITIAL_CONTEXT)                    && properties.containsKey(DATA_SOURCE)) {                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//第一种方式</span>                Context ctx = (Context) initCtx.lookup(properties                        .getProperty(INITIAL_CONTEXT));                dataSource = (DataSource) ctx.lookup(properties                        .getProperty(DATA_SOURCE));            } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (properties.containsKey(DATA_SOURCE)) {                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//第二种方式</span>                dataSource = (DataSource) initCtx.lookup(properties                        .getProperty(DATA_SOURCE));            }        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (NamingException e) {            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> DataSourceException(                    <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"There was an error configuring JndiDataSourceTransactionPool. Cause: "</span> + e, e);        }    }    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**     * 直接返回数据源     *      因为数据源交由服务器托管，因此mybatis不需要再像pooled类型那样自己实现连接池并通过动态代理增强java.sql.Connection     */</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> DataSource <span class="hljs-title" style="box-sizing: border-box;">getDataSource</span>() {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> dataSource;    }    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Properties <span class="hljs-title" style="box-sizing: border-box;">getEnvProperties</span>(Properties allProps) {        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String PREFIX = ENV_PREFIX;        Properties contextProperties = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Entry<Object, Object> entry : allProps.entrySet()) {            String key = (String) entry.getKey();            String value = (String) entry.getValue();            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (key.startsWith(PREFIX)) {                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (contextProperties == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {                    contextProperties = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Properties();                }                contextProperties.put(key.substring(PREFIX.length()), value);            }        }        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> contextProperties;    }}</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><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li><li style="box-sizing: border-box; padding: 0px 5px;">66</li><li style="box-sizing: border-box; padding: 0px 5px;">67</li><li style="box-sizing: border-box; padding: 0px 5px;">68</li><li style="box-sizing: border-box; padding: 0px 5px;">69</li><li style="box-sizing: border-box; padding: 0px 5px;">70</li><li style="box-sizing: border-box; padding: 0px 5px;">71</li><li style="box-sizing: border-box; padding: 0px 5px;">72</li><li style="box-sizing: border-box; padding: 0px 5px;">73</li><li style="box-sizing: border-box; padding: 0px 5px;">74</li><li style="box-sizing: border-box; padding: 0px 5px;">75</li><li style="box-sizing: border-box; padding: 0px 5px;">76</li><li style="box-sizing: border-box; padding: 0px 5px;">77</li><li style="box-sizing: border-box; padding: 0px 5px;">78</li><li style="box-sizing: border-box; padding: 0px 5px;">79</li><li style="box-sizing: border-box; padding: 0px 5px;">80</li><li style="box-sizing: border-box; padding: 0px 5px;">81</li><li style="box-sizing: border-box; padding: 0px 5px;">82</li><li style="box-sizing: border-box; padding: 0px 5px;">83</li><li style="box-sizing: border-box; padding: 0px 5px;">84</li><li style="box-sizing: border-box; padding: 0px 5px;">85</li><li style="box-sizing: border-box; padding: 0px 5px;">86</li><li style="box-sizing: border-box; padding: 0px 5px;">87</li><li style="box-sizing: border-box; padding: 0px 5px;">88</li><li style="box-sizing: border-box; padding: 0px 5px;">89</li><li style="box-sizing: border-box; padding: 0px 5px;">90</li><li style="box-sizing: border-box; padding: 0px 5px;">91</li><li style="box-sizing: border-box; padding: 0px 5px;">92</li><li style="box-sizing: border-box; padding: 0px 5px;">93</li><li style="box-sizing: border-box; padding: 0px 5px;">94</li><li style="box-sizing: border-box; padding: 0px 5px;">95</li><li style="box-sizing: border-box; padding: 0px 5px;">96</li><li style="box-sizing: border-box; padding: 0px 5px;">97</li></ul>

2. 代码范例

MyBatis中使用tomcat的JNDI服务，操作步骤如下：
A. 导入jar包到tomat lib目录中，数据库驱动包需要导入，如果使用DBCP则无需导入（tomcat已经集成了），但是使用其他数据源技术则需要导入；
B. 配置/META-INF/context.xml文件，在tomcat中注册JNDI服务，配置文件内容和第一节tomcat jndi一模一样，不需要任何变化，配置项的详细解释请看第一节。

<code class="hljs xml 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-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-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-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);">Context</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);">Resource</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);">"jdbc/mybatis-jndi"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">auth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"Container"</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);">"javax.sql.DataSource"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxActive</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"100"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxIdle</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"30"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">maxWait</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10000"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">username</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"root"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">password</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"51NByes!"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">driverClassName</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"com.mysql.jdbc.Driver"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">url</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"jdbc:mysql://localhost:3306/javadb"</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);">Context</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></ul>

C. 配置mybatis-config.xml文件，告诉mybatis启用JNDI类型数据源，并将注册服务的名称以及对应服务器的JNDI目录注入mybatis JNDI工厂类中，完成注册。

<code class="hljs xml 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-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-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 configuration  PUBLIC "-//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-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-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-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);">"JNDI"</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);">"data_source"</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/mybatis-jndi"</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);">"initial_context"</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);">"java:/comp/env"</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);">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></ul>

细节：
a. 数据源无需手动获取，最后会被注入到SqlSessionFactory中，对使用mybatis的程序员来说透明，只需要以上三个步骤即可；
b. 如果想手动验证是否配置成功，除了直接使用SqlSessionFactory进行操作验证之外，本处还提供另一种方式直接获取数据源，在mybatis-config.xml中两种配置方式检测代码以及检测结果截图如下：

第一种方式

第二种方式

附注：
本文如有错漏，烦请不吝指正，谢谢！

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