mybatis中配置中引入properties文件

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE configuration
 3   PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 4   "http://mybatis.org/dtd/mybatis-3-config.dtd">
 5 <configuration>
 6  <!--引入外部properties文件  -->
 7  <properties resource="db.properties"></properties>
 8 <!--和Spring整合后 environments 配置将废除 -->
 9   <environments default="development">
10     <environment id="development">
11     <!--使用JDBC事务管理  -->
12       <transactionManager type="JDBC"/>
13       <!--数据库连接池  -->
14       <dataSource type="POOLED">
15         <property name="driver" value="${jdbc.driverClass}"/>
16         <property name="url" value="${jdbc.url}"/>
17         <property name="username" value="${jdbc.username}"/>
18         <property name="password" value="${jdbc.password}"/>
19       </dataSource>
20     </environment>
21   </environments>
22   <!--加载xml文件  -->
23   <mappers>
24     <mapper resource="mapper/UserMapper.xml"/>
25   </mappers>
26 </configuration>