Mybatis之增删改查（CRUD）

package com.Haon.dao;

import com.Haon.pojo.User;

import java.util.List;
import java.util.Map;

public interface UserMapper {
    //定义方法,然后在mapper.xml配置

    //模糊查询
    List getUserLike(String value);

    //查询全部用户
    List getUserList();
    //根据id查询用户


    User getUserByID(int id);


    //根据id查询用户,map实现
    
    User getUserByID2(Map map);


    //插入一条用户数据
    int addUser(User user);


    //插入一条数据之万能的map
    int addUser2(Map map);


    //修改用户数据
    int updateUser(User user);


    //删除用户数据
    int DeleteUser(int id);
}

    
    
        select * from user
    
    
    
        select * from user where name like #{value}
    
    
        select * from user where id=#{id}
    
    
    
        select * from user where id=#{id} and name=#{name}
    
    
    
        insert into user values (#{id},#{name},#{password})
    
    
    
        insert into user values (#{myid},#{myname},#{mypassword})
    
    
    
        update user set name=#{name},password=#{password} where id=#{id}
    
    
    
        delete from user where id=#{id}
    

package com.Haon.pojo;

public class User {
    private int id;
    private String name;
    private  String password;
//定义有参构造
    public User(int id, String name, String password) {
        this.id = id;
        this.name = name;
        this.password = password;
    }
    //定义无参构造
    public User(){}
    //getter,setter

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getPassword() {
        return password;
    }

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

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

    public void setPassword(String password) {
        this.password = password;
    }
    //重写tostring

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

package com.Haon.utils;

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;
//第一步：配置mybatis核心配置文件mybatis-config.xml，不能有中文注释！！！！
//第二步：编写工具类
//第三步：编写实体类User
//第四步：编写持久化层接口和mapper(mapper中也不能有中文注释！！！！)
//第五步：把dao层的mapper绑定到mybatis-config.xml
//第六步：在pom.xml中解决maven约定大于配置的问题。
//第七步：在test/java下编写测试类测试，测试类架构和main下的结构保持相同
public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        //使用mybatis获取SqlSessionFactory对象
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    

    public static SqlSession getSqlSession(){
        return  sqlSessionFactory.openSession();
    }
}

package com.Haon.dao;

import com.Haon.pojo.User;
import com.Haon.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TestUserDao {
    @Test
    public void TestGetUserList(){
        //获得SqlSession
        SqlSession sqlSession= MybatisUtils.getSqlSession();
        //用sqlSession.getMapper(UserMapper.class);获得UserMapper的对象
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        //执行方法
        List userList=userMapper.getUserList();
        //遍历结果集
        for (User user:userList){
            System.out.println(user);
        }
        sqlSession.close();
    }

    @Test
    public void TestGetUserByID(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        User user=userMapper.getUserByID(2);
        System.out.println(user);
        sqlSession.close();
    }
    @Test
    public void TestGetUserByID2(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        Map map=new HashMap();
        map.put("id",5);
        map.put("name","可可");
        User user=userMapper.getUserByID2(map);
        System.out.println(user);
        sqlSession.close();
    }
    //模糊查询
    @Test
    public void TestGetUserLike(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);

        List userList=userMapper.getUserLike("%可%");
        for (User user:userList){
            System.out.println(user);
        }
        sqlSession.close();
    }
    @Test
    //增删改需要提交事务，切记！
    public void TestAddUser(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        userMapper.addUser(new User(3,"虞俊文","147"));
        //必须要的！！
        sqlSession.commit();
        sqlSession.close();
    }
    //用map插入数据
    @Test
    public void TestAddUser2(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        Map map=new HashMap();
        map.put("myid",5);
        map.put("myname","可可");
        map.put("mypassword","147");
        userMapper.addUser2(map);
        //必须要的！！
        sqlSession.commit();
        sqlSession.close();
    }



    @Test
    public void TestUpdateUser(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        userMapper.updateUser(new User(3,"虞俊文是小胖","147"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void TestDeleteUser(){
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);
        userMapper.DeleteUser(3);
        sqlSession.commit();
        sqlSession.close();
    }
}