Mybatis CURD （增删改查）

CURD （增删改查）

命名空间（Namespaces）

namespaces中的包名要和mapper接口的包名一致

1. 示例 《增删改要提交事务》

选择，查询语句

• id:对应namespace中的方法名

• resultType:sql语句执行的返回值

• parameterType：参数类型

  package com.zsq.mapper;
  ​
  import com.zsq.entity.User;
  ​
  import java.util.List;
  ​
  public interface UserMapper {
      // 获取全部用户
      List<User> getAllUser();
  ​
      // 根据用户ID会对应用户
      User getOneUserById(int uid);
  ​
      // 添加用户
      int addUser(User user);
  ​
      // 修改用户信息
      int updateUserById(User user);
  ​
      // 根据用户ID删除对应用户
      int deleteUserById(int uid);
  ​
  }
  ​

  <?xml version="1.0" encoding="UTF8" ?>
  <!DOCTYPE mapper
          PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
          "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  <mapper namespace="com.zsq.mapper.UserMapper">
      <select id="getAllUser" resultType="com.zsq.entity.User">
          select * from `user`
      </select>
  ​
      <select id="getOneUserById" parameterType="int" resultType="com.zsq.entity.User">
          select * from `user` where id = #{uid}
      </select>
  ​
      <insert id="addUser" parameterType="com.zsq.entity.User">
          insert into `user`(id,name,pws) value (#{id},#{name},#{pws})
      </insert>
  ​
      <update id="updateUserById" parameterType="com.zsq.entity.User">
          update `user` set name = #{name},pws = #{pws} where id = #{id}
      </update>
  ​
      <delete id="deleteUserById" parameterType="int">
          delete from `user` where id = #{uid}
      </delete>
  </mapper>

  package com.zsq.entity;
  ​
  import com.zsq.entity.User;
  import com.zsq.mapper.UserMapper;
  import com.zsq.untils.MybatisUntil;
  import org.apache.ibatis.session.SqlSession;
  import org.junit.Test;
  ​
  import java.util.List;
  ​
  public class Test01 {
  ​
      @Test
      public void selectUserListTest(){
          SqlSession sqlSession = MybatisUntil.getSqlSession();
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
          List<User> allUser = mapper.getAllUser();
          for (User user : allUser) {
              System.out.println(user.toString());
          }
          sqlSession.close();
      }
  ​
      @Test
      public void getOneUserByIdTest(){
          SqlSession sqlSession = MybatisUntil.getSqlSession();
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
          User oneUserById = mapper.getOneUserById(2);
          System.out.println(oneUserById.toString());
          sqlSession.close();
      }
  ​
      @Test
      public void addUserTest(){
          User user = new User(3,"新郑","123456");
          SqlSession sqlSession = MybatisUntil.getSqlSession();
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
          int i = mapper.addUser(user);
          if (i > 0) System.out.println("添加用户成功！");
          sqlSession.commit();
          sqlSession.close();
      }
  ​
      @Test
      public void updateUserById(){
          User user = new User(3,"新郑修改","123456");
          SqlSession sqlSession = MybatisUntil.getSqlSession();
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
          int i = mapper.updateUserById(user);
          if (i > 0) System.out.println("更新用户成功！");
          sqlSession.commit();
          sqlSession.close();
      }
  ​
      @Test
      public void deleteUserById(){
          SqlSession sqlSession = MybatisUntil.getSqlSession();
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
          int i = mapper.deleteUserById(2);
          if (i > 0) System.out.println("删除用户成功！");
          sqlSession.commit();
          sqlSession.close();
      }
  ​
  }
  ​

2.MAP类型

假设，我们的实体类，或者数据库表中，字段或参数过多，我们应当考虑使用Map!

• 定义接口

​
    // 添加用户Map类型
    int addUser2(Map<String,Object> property);

• 接口绑定

      <insert id="addUser2" parameterType="map">
          insert into `user`(id,name,pws) value (#{userid},#{username},#{password})
      </insert>  
  ​

• 测试

   @Test
      public void addUserTest2(){
          SqlSession sqlSession = MybatisUntil.getSqlSession();
  ​
          UserMapper mapper = sqlSession.getMapper(UserMapper.class);
  ​
          Map<String,Object> map = new HashMap<String, Object>();
          map.put("userid",55);
          map.put("username","mapAdd");
          map.put("password","123456");
          mapper.addUser2(map);
          sqlSession.commit();
          sqlSession.close();
      }

3.模糊查询

• 定义接口

​
   // 模糊查询
    List<User> getUserListLike(String value);

• 接口绑定

       <select id="getUserListLike" parameterType="String" resultType="com.zsq.entity.User">
          select * from `user` where name like #{value}
      </select> 
  ​

• 测试

　　

@Test
public void getUserListLikeTest(){
SqlSession sqlSession = MybatisUntil.getSqlSession();

UserMapper mapper = sqlSession.getMapper(UserMapper.class);

List<User> userListLike = mapper.getUserListLike("%新%");
for (User user : userListLike) {
System.out.println(user.toString());
}

sqlSession.close();
}