mybatis-plus保姆版

打开idea开始上号啦

 

 pom.xml 文件 ,   <dependency>放入</dependencies>内。

   <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </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>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.23</version>
        </dependency>


        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <!--         将对象 转化为JSON格式-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.76</version>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
        </dependency>

           <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

刷新依赖

resoucrces创建application.yml 注意位置不能错 更不能打错 不然起不到配置的作用。

配置填写信息

server:
  port: 9527
spring:
  datasource:
    druid:
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://数据库地址:3306/数据库名称?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
      username: 用户名
      password:数据库密码


mybatis-plus:
  configuration:
    map-underscore-to-camel-case: true
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  global-config:
    db-config:
      id-type: ASSIGN_ID
  type-aliases-package: com.example.ball.entity

 数据库连接：（连接数据库是为了使用lombok 方便编写代码）

 连接成功后 运行一下启动类

 

 创建文件夹：

创建对应的类

 Result类：

package com.example.ball.common;

import lombok.Data;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

@Data
public class Result<T> implements Serializable {

    private Integer code; //编码：1成功，0和其它数字为失败

    private String msg; //错误信息

    private T data; //数据

    private Map map = new HashMap(); //动态数据

    public static <T> Result<T> success(T object) {
        Result<T> res = new Result<T>();
        res.data = object;
        res.code = 1;
        return res;
    }


    public static <T> Result<T> error(String msg) {
        Result res = new Result();
        res.msg = msg;
        res.code = 0;
        return res;
    }

    public Result<T> add(String key, Object value) {
        this.map.put(key, value);
        return this;
    }



}

查看数据库字段 对应类型编写实体 

 entity类

package com.example.ball.entity;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
import java.util.Date;


@Data
@TableName("team")
public class Ball {

    private Integer id;
    private String LeftName;
    private String RightName;
    private Integer LeftScore;
    private Integer RightScore;
    private Date CreateDate;

}

mapper接口：

package com.example.ball.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.ball.entity.Ball;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface BallMapper extends BaseMapper<Ball> {
}

 service接口:

package com.example.ball.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.ball.entity.Ball;

public interface BallService extends IService<Ball> {
}

impl类:

package com.example.ball.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.ball.entity.Ball;
import com.example.ball.mapper.BallMapper;
import com.example.ball.service.BallService;
import org.springframework.stereotype.Service;

@Service
public class BallServiceImpl extends ServiceImpl<BallMapper, Ball> implements BallService {
}

controller类:

package com.example.ball.controller;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.example.ball.common.Result;
import com.example.ball.entity.Ball;
import com.example.ball.service.BallService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@CrossOrigin   // 跨域问题
@RequestMapping("yz")
@RestController
public class BallController {
    @Autowired
    private BallService ballService;

        @RequestMapping("/get")
    public Result<Ball> get(@RequestParam String id){

        LambdaQueryWrapper<Ball> queryWrapper= new LambdaQueryWrapper<>();
        queryWrapper.eq(Ball::getId,id);

        Ball ball = ballService.getById(id);
        return com.example.ball.common.Result.success(ball);
    }
}

 查看结果发送请求 ：http://localhost:9527/yz/get?id=2

页面查看是否查询成功。