详解如何继承Mybatis中Mapper.xml文件

package com.test.dao.mapper.srctest;
import com.test.dao.model.srctest.SrcTest;
import com.test.dao.model.srctest.SrcTestExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;
public interface SrcTestMapper {
    long countByExample(SrcTestExample example);
    int deleteByExample(SrcTestExample example);
    int deleteByPrimaryKey(Integer id);
    int insert(SrcTest record);
    int insertSelective(SrcTest record);
    List<SrcTest> selectByExample(SrcTestExample example);
    SrcTest selectByPrimaryKey(Integer id);
    int updateByExampleSelective(@Param("record") SrcTest record, @Param("example") SrcTestExample example);
    int updateByExample(@Param("record") SrcTest record, @Param("example") SrcTestExample example);
    int updateByPrimaryKeySelective(SrcTest record);
    int updateByPrimaryKey(SrcTest record);
}

package com.test.dao.mapper.srctest;
import com.test.dao.model.srctest.SrcTest;
import org.apache.ibatis.annotations.Param;
import javax.annotation.Resource;
import java.util.List;
/**
* SrcTestMapperExt接口
* Created by shirenchuang on 2018/6/30.
*/
@Resource
public interface SrcTestMapperExt extends SrcTestMapper {
    List<SrcTest> selectExtTest(@Param("age") int  age);
}

<?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.test.dao.mapper.srctest.SrcTestMapperExt">
  <resultMap id="BaseResultMap" type="com.test.dao.model.srctest.SrcTest">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="name" jdbcType="VARCHAR" property="name" />
    <result column="age" jdbcType="INTEGER" property="age" />
    <result column="ctime" jdbcType="BIGINT" property="ctime" />
  </resultMap>
<!-- 省略....-->
</mapper>

<?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.test.dao.mapper.srctest.SrcTestMapperExt">
    <select id="selectExtTest" resultMap="BaseResultMap">
        select * from src_test where age>#{age}
    </select>
</mapper>

Caused by: org.apache.ibatis.builder.BuilderException: Wrong namespace. Expected 'com.test.dao.mapper.srctest.SrcTestMapper' but found 'com.test.dao.mapper.srctest.SrcTestMapperExt'.

  public void setCurrentNamespace(String currentNamespace) {
    if (currentNamespace == null) {
      throw new BuilderException("The mapper element requires a namespace attribute to be specified.");
    }
    if (this.currentNamespace != null && !this.currentNamespace.equals(currentNamespace)) {
      throw new BuilderException("Wrong namespace. Expected '"
          + this.currentNamespace + "' but found '" + currentNamespace + "'.");
    }
    this.currentNamespace = currentNamespace;
  }

  public void parse() {
    String resource = type.toString();
    if (!configuration.isResourceLoaded(resource)) {
      loadXmlResource();
      configuration.addLoadedResource(resource);
      assistant.setCurrentNamespace(type.getName());
      parseCache();
      parseCacheRef();
      Method[] methods = type.getMethods();
      for (Method method : methods) {
        try {
          // issue #237
          if (!method.isBridge()) {
            parseStatement(method);
          }
        } catch (IncompleteElementException e) {
          configuration.addIncompleteMethod(new MethodResolver(this, method));
        }
      }
    }
    parsePendingMethods();
  }

  @Override
  protected void checkDaoConfig() {
    super.checkDaoConfig();
    notNull(this.mapperInterface, "Property 'mapperInterface' is required");
    Configuration configuration = getSqlSession().getConfiguration();
    if (this.addToConfig && !configuration.hasMapper(this.mapperInterface)) {
      try {
        configuration.addMapper(this.mapperInterface);
      } catch (Exception e) {
        logger.error("Error while adding the mapper '" + this.mapperInterface + "' to configuration.", e);
        throw new IllegalArgumentException(e);
      } finally {
        ErrorContext.instance().reset();
      }
    }
  }

    <!-- Mapper接口所在包名，Spring会自动查找其下的Mapper -->
    <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.test.dao.mapper"/>
<!--
        该属性实际上就是起到一个过滤的作用，如果设置了该属性，那么MyBatis的接口只有包含该注解，才会被扫描进去。
-->
        <property name="annotationClass" value="javax.annotation.Resource"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

/**
* SrcTestMapperExt接口
* Created by shirenchuang on 2018/6/30.
*/
@Resource
public interface SrcTestMapperExt extends SrcTestMapper {
    List<SrcTest> selectExtTest(@Param("age") int  age);
}

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <!-- 必须将mapper,和mapperExt也一起扫描-->
        <property name="mapperLocations" value="classpath:com/test/dao/mapper/**/*.xml"/>
    </bean>

  @Test
    public void selectExt(){
        List<SrcTest> tests = srcTestService.selectExtTest(9);
        System.out.println(tests.toString());
    }