MyBatis其他方式來實現(xiàn)多表查詢的操作

利用Java中的集合框架（List，Map）

其中List存儲多個查詢返回的記錄

Map查詢返回字段，同時記錄表中一條數(shù)據(jù)

<?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.zlt.mapper.StudentMapper_2">

?<select id="getStudent" resultType="java.util.HashMap">

? ? ? ? SELECT sid,sname,a.t_id,t_name FROM student a, teacher b WHERE a.t_id=b.t_id

?</select> </mapper>

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package com.zlt.test;

import java.io.IOException;

import java.io.Reader;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.apache.ibatis.io.Resources;

import org.apache.ibatis.session.SqlSession;

import org.apache.ibatis.session.SqlSessionFactory;

import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import org.junit.Test;

import com.zlt.pojo.Student;

import com.zlt.pojo.Teacher;

import com.zlt.pojo.Team;

public class Test03 {

?private static SqlSessionFactorysqlSessionFactory;

?private static Reader reader;

?static {

?try {

? ? ? ? ? ? reader = Resources.getResourceAsReader("config.xml");

? ? ? ? ? ? sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

? ? ? ? } catch (IOException e) {

? ? ? ? ? ? e.printStackTrace();

? ? ? ? }

? ? }

? ? @Test

?public void m01() {

? ? ? ? SqlSessionsqlSession = sqlSessionFactory.openSession();

? ? ? ? String sql = "com.zlt.mapper.StudentMapper.getStudent";

? ? ? ? List<Student> list = sqlSession.selectList(sql);

?for (Student student : list) {

? ? ? ? ? ? System.out.println(student.getSname() + "====" + student.getTeacher().getT_name());

? ? ? ? }

? ? ? ? sqlSession.close();

? ? }

? ? @Test

?public void m02() {

? ? ? ? SqlSessionsqlSession = sqlSessionFactory.openSession();

? ? ? ? String sql = "com.zlt.mapper.TeacherMapper.getTeacher";

? ? ? ? Teacher teacher = sqlSession.selectOne(sql);

? ? ? ? List<Student> student = teacher.getStudent();

?for (Student s : student) {

? ? ? ? ? ? System.out.println(teacher.getT_name() + "===" + s.getSname());

? ? ? ? }

? ? ? ? sqlSession.close();

? ? }

? ? @Test

?public void m03() {

? ? ? ? SqlSessionsqlSession = sqlSessionFactory.openSession();

? ? ? ? String sql = "com.zlt.mapper.StudentMapper_2.getStudent";

? ? ? ? List<Map<String, Object>> list = sqlSession.selectList(sql);

? ? ? ? System.out.println(list);

? ? ? ? sqlSession.close();

? ? }

}