mybatis10–自连接多对一查询详解编程语言

public interface TeacherDao { 
    /** 
     * 根据老师的编号查询所有的导师信息 
     */ 
    Teacher selectTeahcerById(Integer tId); 
}

<?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="cn.bdqn.dao.TeacherDao"> 
 
    <resultMap type="Teacher" id="teacherMap"> 
      <id property="id" column="id"/> 
      <result property="name" column="name"/> 
      <!-- 设置关联集合的属性   递归查询 把查询到的tid当作id再次查询上级的导师信息 --> 
      <association property="teacher" javaType="Teacher" 
       select="selectTeahcerById" column="tid"/> 
    </resultMap> 
  
     <select id="selectTeahcerById" resultMap="teacherMap"> 
      select  id,name,tid from  teacher where id=#{xxx} 
    </select> 
     
</mapper>

    /** 
     * 根据老师的编号查询所有的导师信息 
     */ 
    @Test 
    public void test1() { 
        Teacher teacher = dao.selectTeahcerById(8); 
        System.out.println(teacher); 
    }