MybatisPlus实现简单增删改查功能

<dependencies>

   <dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-web</artifactId>

   </dependency>

   <dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-devtools</artifactId>

    <scope>runtime</scope>

    <optional> true </optional>

   </dependency>

   <dependency>

    <groupId>mysql</groupId>

    <artifactId>mysql-connector-java</artifactId>

    <scope>runtime</scope>

   </dependency>

   <dependency>

    <groupId>org.projectlombok</groupId>

    <artifactId>lombok</artifactId>

    <optional> true </optional>

   </dependency>

   <dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-test</artifactId>

    <scope>test</scope>

   </dependency>

  </dependencies>

<dependency>

    <groupId>com.baomidou</groupId>

    <artifactId>mybatis-plus-boot-starter</artifactId>

    <version> 3.3 . 1 .tmp</version>

   </dependency>

#mysql5 驱动不同

spring.datasource.username=root

spring.datasource.password= 123456

spring.datasource.url=jdbc:mysql: //localhost:3306/mybatisplus?useSSL=false&useUnicode=true&characterEncoding=utf-8

spring.datasource.driver- class -name=com.mysql.cj.jdbc.Driver

#配置日志

mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

#建表

DROP TABLE IF EXISTS user;

CREATE TABLE user

(

     id BIGINT( 20 ) NOT NULL COMMENT '主键ID' ,

     name VARCHAR( 30 ) NULL DEFAULT NULL COMMENT '姓名' ,

     age INT( 11 ) NULL DEFAULT NULL COMMENT '年龄' ,

     email VARCHAR( 50 ) NULL DEFAULT NULL COMMENT '邮箱' ,

     PRIMARY KEY (id)

);

#插入数据

DELETE FROM user;

INSERT INTO user (id, name, age, email) VALUES

( 1 , 'Jone' , 18 , 'test1@baomidou测试数据' ),

( 2 , 'Jack' , 20 , 'test2@baomidou测试数据' ),

( 3 , 'Tom' , 28 , 'test3@baomidou测试数据' ),

( 4 , 'Sandy' , 21 , 'test4@baomidou测试数据' ),

( 5 , 'Billie' , 24 , 'test5@baomidou测试数据' );

package com.sh.entity;

import com.baomidou.mybatisplus.annotation.IdType;

import com.baomidou.mybatisplus.annotation.TableId;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

import org.springframework.context.annotation.Primary;

import java.util.Date;

@Data

@AllArgsConstructor

@NoArgsConstructor

public class User {

  @TableId (value = "id" ,type = IdType.AUTO)

  private Integer id;

  private String name;

  private Integer age;

  private String email;

  private Date createTime;

  private Date updateTime;

}

package com.sh.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;

import com.sh.entity.User;

import org.springframework.stereotype.Repository;

@Repository

public interface UserMapper extends BaseMapper<User> {

}

package com.sh.controller;

import com.sh.entity.User;

import com.sh.mapper.UserMapper;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.*;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

@RestController

public class UserController {

  @Autowired

  private UserMapper userMapper;

  //查询 查询所以 null 就是没有条件

  @GetMapping ( "/selectUser" )

  public List<User> getAll(){

   List<User> user = userMapper.selectList( null );

   return user;

  }

  //根据id查询

  @GetMapping ( "/selectById" )

  public User selectUserById(){

   User user = userMapper.selectById( 1 );

   return user;

  }

  //根据多个id查询 Arrays.asList集合

  @GetMapping ( "/selectByIds" )

  public List<User> selectUserByIds(){

   List<User> user = userMapper.selectBatchIds(Arrays.asList( 1 , 2 , 3 ));

   return user;

  }

  //添加

  @PostMapping ( "/insertUser" )

  public Integer insertUsers(User user){

   Integer result = userMapper.insert(user);

   return result;

  }

  //修改 根据id

  @PutMapping ( "/updateUser" )

  public Integer updateUsers(User user){

   Integer result = userMapper.updateById(user);

   return result;

  }

  //删除 根据id

  @DeleteMapping ( "/deleteUser" )

  public Integer deleteUsers(Integer id){

   Integer result = userMapper.deleteById(id);

   return result;

  }

}