1_sqlSession查询的三种方式

@AllArgsConstructor
@NoArgsConstructor
@Data
public class Emp implements Serializable {
    private Integer empno;
    private String ename;
    private String job;
    private Integer mgr;
    private Date hiredate;
    private Double sal;
    private Double comm;
    private Integer deptno;
}

        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

    
    
        select * from emp where empno = 7499
    
    
    
        select * from emp
    
    
    
        select * from emp
    

package com.msb.test;
import com.msb.pojo.Dept;
import com.msb.pojo.Emp;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
 * @Author: Ma HaiYang
 * @Description: MircoMessage:Mark_7001
 */
public class Test2 {
    private SqlSession sqlSession;
    @Before
    public void init(){
        SqlSessionFactoryBuilder ssfb =new SqlSessionFactoryBuilder();
        InputStream resourceAsStream = null;
        try {
            resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        } catch (IOException e) {
            e.printStackTrace();
        }
        SqlSessionFactory factory=ssfb.build(resourceAsStream) ;
        sqlSession=factory.openSession();
    }
    @Test
    public void testSelectOne(){
        // 查询单个对象
        System.out.println("sqlSession查询单个对象");
        Emp emp = sqlSession.selectOne("findOne");
        System.out.println(emp);
    }
    @Test
    public void testSelectList(){
        // 查询多个对象的List集合
        System.out.println("sqlSession查询对象List集合");
        List emps = sqlSession.selectList("EmpMapper.findAll");
        emps.forEach(System.out::println);
    }
    @Test
    public void testSelectMap(){
        // 查询多个对象的Map集合
        System.out.println("sqlSession查询对象Map集合");
        Map empMap = sqlSession.selectMap("findEmpMap", "EMPNO");
        Set empnos = empMap.keySet();
        for (Integer empno : empnos) {
            System.out.println(empno+" :" +empMap.get(empno));
        }
    }
    @After
    public void release(){
        // 关闭SQLSession
        sqlSession.close();
    }
}