mybatis 在typeAliases别名时报错的解决

<?xml version="1.0" encoding="UTF-8" ?>
<!-- dtd约束 -->
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
  <settings>
  	<!-- 使用驼峰命名法 -->
  	<setting name="mapUnderscoreToCamelCase" value="true"/>
  </settings>
  <!-- ####################################################  -->
   <typeAliases>
   		<!--typeAlias子标签：设置单个类型的别名
   			type:pojo或vo的数据类型，值为全限定名
   			alias:别名，一般都使用类的简单名称
   		  -->	
   		<typeAlias type="com.mybatis.pojo.User" alias="user"/>
   		<!-- <typeAlias type="com.mybatis.pojo.XXX" alias="xxx"/> -->
   </typeAliases>
   <!-- ####################################################  -->
  <environments default="dev_mysql">
    <environment id="dev_mysql">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/gj1?characterEncoding=utf8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
  	<mapper resource="com\mybatis\mapper\UserMapper.xml"/>
  </mappers>
</configuration>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.mapper.UserMapper">
    <!-- 单行查询功能
      resultType : 返回类型，必须和对应映射接口方法的返回类型一致，值必须为全限定名
      此时的resultType必须跟mybatis-config.xml中alias属性值一致
     -->
     <select id="selectByPrimaryKey" parameterType="int" resultType="user">
      select id u_c_a_id,username u_c_a_name,password u_c_a_pwd,age from user where id=#{id}
     </select>
     
</mapper>

<?xml version="1.0" encoding="UTF-8" ?>
<!-- dtd约束 -->
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
  <settings>
  	<!-- 使用驼峰命名法 -->
  	<setting name="mapUnderscoreToCamelCase" value="true"/>
  </settings>
<!--    <typeAliases>
   		typeAlias子标签：设置单个类型的别名
   			type:pojo或vo的数据类型，值为全限定名
   			alias:别名，一般都使用类的简单名称
   		 	
   		<typeAlias type="com.mybatis.pojo.User" alias="user"/>
   		<typeAlias type="com.mybatis.pojo.XXX" alias="xxx"/>
   </typeAliases> -->
    <!-- ####################################################  -->
   <typeAliases>
   		<!--
   			package标签：使用包扫描配置别名
   			为对应包下面的所有类都取了别名
   			默认使用简单的名称作为别名
   		  -->	
   		<package name="com.mybatis.pojo"/>
   </typeAliases>
   <!-- ####################################################  -->
  <environments default="dev_mysql">
    <environment id="dev_mysql">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/gj1?characterEncoding=utf8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
  	<mapper resource="com\mybatis\mapper\UserMapper.xml"/>
  </mappers>
</configuration>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mybatis.mapper.UserMapper">
    <!-- 单行查询功能
      resultType : 返回类型，必须和对应映射接口方法的返回类型一致，值必须为全限定名
      此时的resultType为pojo的简单名，可以为user，也可以为User
     -->
     <select id="selectByPrimaryKey" parameterType="int" resultType="user">
      select id u_c_a_id,username u_c_a_name,password u_c_a_pwd,age from user where id=#{id}
     </select>     
</mapper>