Mybatis搭建环境准备

        
        
        
            org.mybatis
            mybatis
            3.5.6
        

若是复制运行报错，把注释去掉

    
    
        select * from student
    

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 java.io.IOException;
import java.io.InputStream;

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;

    static {
        try {
            //使用Mybatis第一步，获取sqlSessionFactory对象
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //既然有了 SqlSessionFactory，顾名思义，我们可以从中获得 SqlSession 的实例。
    //SqlSession 提供了在数据库执行 org.apache.ibatis.jdbc.SQL 命令所需的所有方法。
    // 你可以通过SqlSession 实例来直接执行已映射的 SQL 语句
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();	//不会提交事务 （增删改，则在增删改中添加commit）
      //return sqlSessionFactory.openSession(true);  //会自动提交事务
    }
}

实体类

package com.xiao.pojo;

public class User{
    private int id;
    private String name;
    private String pwd;

    public User() {

    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + ''' +
                ", pwd='" + pwd + ''' +
                '}';
    }
}

DAO接口

package com.xiao.dao;

import com.xiao.pojo.User;
import java.util.List;

public interface UserDao {
    List getUserList();
}

Test测试

import java.util.List;

public class StudentTest {
    @Test
    public void userTest(){
        //第一步获取SqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();

        //方式一：getMapper()
        UserDao mapper = sqlSession.getMapper(UserDao.class);
        List userList = mapper.getUserList();

        //方式二
//        List userList = sqlSession.selectList("com.xiao.dao.UserDao.getUserList");

        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }
}