spring boot + mybatis-plus + MySql建立接口_mysql+mybatis+spring 写接口

1、项目结构

2、pom配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.school</groupId>
    <artifactId>study</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>study</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


<!--        swagger-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.2</version>
        </dependency>

        <!--        不加这个就报Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException-->
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>20.0</version>
        </dependency>


        <!--           lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!--        mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.6.1</version>
            </plugin>
        </plugins>
    </build>

</project>

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3、application配置

spring:
  profiles:
    active: dev
  datasource:
    username: root
    password: root
    url: jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
server:
  port: 9000
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4、书写实体类

package com.school.study.pojo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @author 又菜又爱玩
 * @version 1.0
 * @date 2021/12/10 14:15
 * @blog https://blog.csdn.net/biancheng4/article/details/121727982
 */

@ApiModel("用户实体类")  //swagger-ui
@Data //等同于set/get方法
@AllArgsConstructor  //构造函数
@NoArgsConstructor  // 生成一个无参数的构造方法
public class user {
    @ApiModelProperty(value = "用户id唯一主键")
    @TableId(type = IdType.AUTO)
    private Integer id;
    @ApiModelProperty("用户名")
    private String username;
    @ApiModelProperty("密码")
    private Integer password;

}

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5、书写Mapper接口

package com.school.study.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.school.study.pojo.user;
import org.apache.ibatis.annotations.Mapper;

/**
 * @author 又菜又爱玩
 * @version 1.0
 * @date 2021/12/10 14:27
 * @blog https://blog.csdn.net/biancheng4/article/details/121727982
 */

@Mapper
public interface userMapper extends BaseMapper<user> {
}

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继承了BaseMapper类，类中已经写好了增删改查的方法ctrl点击打开BaseMapper就可以看见这些方法，当然也可以自己重写这些方法

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.baomidou.mybatisplus.core.mapper;

import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Param;

public interface BaseMapper<T> {
    int insert(T var1);

    int deleteById(Serializable var1);

    int deleteByMap(@Param("cm") Map<String, Object> var1);

    int delete(@Param("ew") Wrapper<T> var1);

    int deleteBatchIds(@Param("coll") Collection<? extends Serializable> var1);

    int updateById(@Param("et") T var1);

    int update(@Param("et") T var1, @Param("ew") Wrapper<T> var2);

    T selectById(Serializable var1);

    List<T> selectBatchIds(@Param("coll") Collection<? extends Serializable> var1);

    List<T> selectByMap(@Param("cm") Map<String, Object> var1);

    T selectOne(@Param("ew") Wrapper<T> var1);

    Integer selectCount(@Param("ew") Wrapper<T> var1);

    List<T> selectList(@Param("ew") Wrapper<T> var1);

    List<Map<String, Object>> selectMaps(@Param("ew") Wrapper<T> var1);

    List<Object> selectObjs(@Param("ew") Wrapper<T> var1);

    IPage<T> selectPage(IPage<T> var1, @Param("ew") Wrapper<T> var2);

    IPage<Map<String, Object>> selectMapsPage(IPage<T> var1, @Param("ew") Wrapper<T> var2);
}


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6、书写Service接口

package com.school.study.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.school.study.pojo.user;
import org.springframework.stereotype.Service;


/**
 * @author 又菜又爱玩
 * @version 1.0
 * @date 2021/12/10 14:32
 * @blog https://blog.csdn.net/biancheng4/article/details/121727982
 */

public interface userService extends IService<user> {
     //增加
    boolean addUser(user user);
     //删除
    boolean deleteUser(int id);
    //更新
    boolean updateUser(user user);
    //查找
    user findUserById(int id);



}

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7、书写service的impl类

package com.school.study.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.school.study.mapper.userMapper;
import com.school.study.pojo.user;
import com.school.study.service.userService;
import org.apache.catalina.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * @author 又菜又爱玩
 * @version 1.0
 * @date 2021/12/10 14:43
 * @blog https://blog.csdn.net/biancheng4/article/details/121727982
 */

@Service
public class userServiceImpl extends ServiceImpl<userMapper, user> implements userService {

    //增删改返回布尔值，判断是否成功
    @Override
    public boolean addUser(user user) {
        int i = baseMapper.insert(user);
        return i > 0;

    }

    @Override
    public boolean deleteUser(int id) {
        int i = baseMapper.deleteById(id);
        return i > 0;

    }

    @Override
    public boolean updateUser(user user) {
        int i = baseMapper.updateById(user);
        return i > 0;
    }

    @Override
    public user findUserById(int id) {
        return baseMapper.selectById(id);
    }
}

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8、书写Controller类

package com.school.study.controller;


import com.school.study.pojo.user;
import com.school.study.response.CommonResponse;
import com.school.study.service.userService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

/**
 * @author 又菜又爱玩
 * @version 1.0
 * @date 2021/12/10 15:00
 * @blog https://blog.csdn.net/biancheng4/article/details/121727982
 */

@Api(tags = "用户信息类")
@RestController
public class userController {

    @Autowired
    private userService service;

    @ApiOperation("用Id获取用户信息")
    @GetMapping("/findById")
    public CommonResponse findById(int id){
       return CommonResponse.ok().data("items",  service.findUserById(id));
    }


    //要写RequestBody
    @ApiOperation("插入数据")
    @PostMapping("/insert")
    public CommonResponse insert(@RequestBody user user){
       boolean flag = service.addUser(user);
        if (flag){
            return CommonResponse.ok().data("items", "插入成功");
        } else {
            return CommonResponse.error().data("items", "插入失败");
        }
    }

    @ApiOperation("删除数据")
    @PostMapping("/delete")
    public CommonResponse delete(int id){
        boolean flag = service.deleteUser(id);
        if (flag){
            return CommonResponse.ok().data("items", "删除成功");
        } else {
            return CommonResponse.error().data("items", "删除失败");
        }
    }

    @ApiOperation("更新数据")
    @PostMapping("/upDate")
    public CommonResponse upDate(@RequestBody user user){
        boolean flag = service.updateUser(user);
        if (flag){
            return CommonResponse.ok().data("items", "更新成功");
        } else {
            return CommonResponse.error().data("items", "更新失败");
        }
    }

}

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9、使用swagger进行测试

1.数据库数据

2.增加数据

我的id使用的是自增的，保证唯一性，剩下的就不演示了。