Mybatis配置的错误代码解析

问题：在添加configuration标签的时候，会出现因为位置不对而报错?

The content of element type "configuration" must match " (properties?,settings?,typeAliases?,

typeHandlers?, objectFactory?,objectWrapperFactory?,plugins?,environments?,mappers?)".

 

解决方案：要按照它规定的标签顺序来键入这些标签，如果位置有颠倒将会报错。

          1、<properties></properties>　　 <!-- 属性配置 -->
          2、<settings></settings>　　　　  <!-- 设置缓存和延迟加载等等重要的运行时的行为方式 -->
          3、<typeAliases></typeAliases>　　<!-- 起别名 -->
          4、<typeHandlers></typeHandlers>
          5、<objectFactory type=""></objectFactory>
          6、<objectWrapperFactory type=""></objectWrapperFactory>
          7、<plugins></plugins>
          8、<environments default=""></environments>
          9、<mappers></mappers>

如下面配置所示：

<?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>
           
      <!-- 引用properties文件 -->
      <properties resource="db.properties"></properties>
      
       <typeAliases>
         <typeAlias type="com.maochen.handle.User" alias="_User"/>
     </typeAliases>
     
     <environments default="development">
          <environment id="development">
              <transactionManager type="JDBC" />
              <!-- 配置数据库连接信息 -->
              <dataSource type="POOLED">
                <!--  <property name="driver" value="com.mysql.jdbc.Driver" />
                 <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
                 <property name="username" value="root" />
                 <property name="password" value="123456"/> -->
                 
                 <!-- 优化之后的 -->
                 <property name="driver" value="${driver}" />
                 <property name="url" value="${url}" />
                 <property name="username" value="${name}" />
                 <property name="password" value="${password}" />
             </dataSource>
         </environment>
     </environments>
     <mappers>
         <!-- 注册userMapper.xml文件，userMapper.xml位于me.gacl.mapping这个包下面，所以
         resourse写成me/gacl/mapping/userMapper.xml -->
         <mapper resource="com/maochen/map/userMapper.xml" />
         <!-- 注册userMapperI接口 -->
         <mapper class="com.maochen.map.UserMapperI" />
     </mappers>        
 </configuration>