Mybatis 增删改查 基础小进阶

标签：mapper 进阶 改查 UserMapper sqlSession user Mybatis id User

有部分相同不需要修改可以点击--->简单的Mybatis项目

1.配置Maven依赖

2.配置环境文件mybatis-config.xml

3.编写MybatisUtils工具类

4.编写实体类User

5.实体类UserMapperr的接口  （在小进阶后  实体类名字修改为了UserMapper）

 1 package com.zxy.dao;
 2 
 3 import com.zxy.pojo.User;
 4 
 5 import java.util.List;
 6 
 7 public interface UserMapper {
 8     //获取全部用户
 9     List<User> getUserList();
10 
11     //根据ID查询用户
12     User getUserById(int id);
13 
14     //insert一个用户
15     int addUser(User user);
16 
17     //修改用户
18     int updateUser(User user);
19 
20     //删除一个用户
21     int deleteUser(int id);
22 }

6.编写基于 XML的对于sql的映射语句UserMapper.xml

 增删改不需要返回结果类型

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper
 3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 
 6 
 7 <mapper namespace="com.zxy.dao.UserMapper">
 8     <select id="getUserList" resultType="com.zxy.pojo.User" >
 9         select * from mybatis.user;
10     </select>
11 　　　//查询
12     <select id="getUserById" parameterType="int" resultType="com.zxy.pojo.User">
13         select * from mybatis.user where id = #{id};
14     </select>
15 　　//增加
16     <insert id="addUser" parameterType="com.zxy.pojo.User">
17         insert into mybatis.user(id, name, pwd) VALUES (#{id},#{name},#{pwd})
18     </insert>
19 　　//修改
20     <update id="updateUser" parameterType="com.zxy.pojo.User">
21         update mybatis.user set name =#{name},pwd=#{pwd}  where id = #{id};
22     </update>
23 　　//删除
24     <delete id="deleteUser" parameterType="int">
25         delete from mybatis.user
26                  where id = #{id};
27     </delete>
28 </mapper>

 

7.编写测试类

注意！！！：增删改是需要提交事务  ！！！

有两种方法 1.如下面所示        手动提交 sqlSession.commit();

　　　　　　　2.在工具类MybatisUtils中        

return sqlSessionFactory.openSession(true); 

在括号中传值true  可以设置为自动提交

 

 

1.查询

 1  public void test(){
 2 
 3             //1.获取sqlSession对象
 4             SqlSession sqlSession = MybatisUtils.getSqlSession();
 5             //2.
 6             UserMapper userDao = sqlSession.getMapper(UserMapper.class);
 7             List<User> userList = userDao.getUserList();
 8             for ( User user :userList) {
 9                 System.out.println(user);
10             }
11 
12             //关闭SqlSession
13             sqlSession.close();
14         }
15 
16         @Test
17         public void test2(){
18             SqlSession sqlSession = MybatisUtils.getSqlSession();
19             UserMapper mapper = sqlSession.getMapper(UserMapper.class);
20             User user = mapper.getUserById(1);
21             System.out.println(user);
22             sqlSession.close();
23         }

 

2.增加

 1 @Test
 2         public void test3(){
 3             SqlSession sqlSession = MybatisUtils.getSqlSession();
 4             UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 5             int rs = mapper.addUser(new User(4,"爱德华","44451313"));
 6             if(rs>0){
 7                 System.out.println("插入成功");
 8             }
 9             //提价事务
10             sqlSession.commit();
11             sqlSession.close();
12     }

 

3.修改

1  @Test
2             public void test4() {
3                 SqlSession sqlSession = MybatisUtils.getSqlSession();
4                 UserMapper mapper = sqlSession.getMapper(UserMapper.class);
5                 mapper.updateUser(new User(4,"呵呵","999"));
6                 sqlSession.commit();
7                 sqlSession.close();
8             }

 

4.删除

1  @Test
2             public void test5() {
3                 SqlSession sqlSession = MybatisUtils.getSqlSession();
4                 UserMapper mapper = sqlSession.getMapper(UserMapper.class);
5                 mapper.deleteUser(4);
6                 sqlSession.commit();
7                 sqlSession.close();
8             }

 

标签：mapper,进阶,改查,UserMapper,sqlSession,user,Mybatis,id,User
From： https://www.cnblogs.com/kidzxy/p/16797379.html