MybatisPlus实现简单增删改查功能_Java教程

实现步骤：

工具：IDEA
数据库版本：mysql5.7

一、环境搭建

1.创建springboot项目

pom.xml

2.pom.xml : spring web、lombok mysql

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									<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>

3.添加mybatisplus依赖

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									<dependency>

									   <groupId>com.baomidou</groupId>

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

									   <version>3.3.1.tmp</version>

									  </dependency>

application.properties

4.application.properties配置文件：用户名、密码、连接驱动、配置日志

注意：mysql8 需要增加时区的配置 serverTimezone=GMT%2B8 东八区

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									#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

数据库数据

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									#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.com'),

									(2, 'Jack', 20, 'test2@baomidou.com'),

									(3, 'Tom', 28, 'test3@baomidou.com'),

									(4, 'Sandy', 21, 'test4@baomidou.com'),

									(5, 'Billie', 24, 'test5@baomidou.com');

代码详解

1.新建实体类User
lombok注解详解：
@Data：自动生成get\set方法
@AllArgsConstructor ：有参方法
@NoArgsConstructor：无参方法
@TableId(value = “id”,type = IdType.AUTO) ：给实体设置自增

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									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;

									}

2. 新建mapper包
在mapper包里建UserMappe接口r 继承BaseMapper<实体类>

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									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> {

									}

3.创建控制层controller：
新建UserController类

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									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;

									 }

									}