springboot写增删查改接口

1，搭建好一个spring boot项目

pom.xml

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.6.4
         
    
    com.example
    demo
    0.0.1-SNAPSHOT
    demo
    Demo project for Spring Boot
    
        1.8
    
    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.2.2
        

        
            mysql
            mysql-connector-java
            runtime
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

2，连接数据库

application.properties

server.port=8082

spring.datasource.url=jdbc:mysql://localhost:3306/ssm_db?serverTimezone=GMT%2B8&characterEncoding-utf-8&useSSL=false
spring.datasource.username=root  //mysql用户名
spring.datasource.password=root  //mysql密码
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver


spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

3，编写实体类

创建entity.user

package com.example.demo.entity;


//实体类
public class user {
    private Integer commodity_Id;
    private String name;
    private Double price;
    private String creation_Time;
    private String picture;
    private Integer id;
    private Integer commodityType;
    private Integer commoditySate;

    public Integer getCommodity_Id() {
        return commodity_Id;
    }

    public void setCommodity_Id(Integer commodity_Id) {
        this.commodity_Id = commodity_Id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(Double price) {
        this.price = price;
    }

    public String getCreation_Time() {
        return creation_Time;
    }

    public void setCreation_Time(String creation_Time) {
        this.creation_Time = creation_Time;
    }

    public String getPicture() {
        return picture;
    }

    public void setPicture(String picture) {
        this.picture = picture;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getCommodityType() {
        return commodityType;
    }

    public void setCommodityType(Integer commodityType) {
        this.commodityType = commodityType;
    }

    public Integer getCommoditySate() {
        return commoditySate;
    }

    public void setCommoditySate(Integer commoditySate) {
        this.commoditySate = commoditySate;
    }
}

4，编写控制层

创建controller.UserController

package com.example.demo.controller;


import com.example.demo.entity.user;
import com.example.demo.mapper.userMapper;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;
//解决跨域问题
@CrossOrigin(origins = {"*", "null"})
@RestController
@RequestMapping("/phone")
public class UserController {

    @Resource
    userMapper userMapper;

    @GetMapping
    public List getUser(){
        return userMapper.findAll();
    }
    @PostMapping
    public String addUser(@RequestBody user phone){
        userMapper.save(phone);
        return "添加成功";
    }
    @PutMapping
    public String updateUser(@RequestBody user phone) {
        userMapper.updateById(phone);
        return "更新成功";
    }

}

5，编写持久层

创建mapper.userMapper

package com.example.demo.mapper;


import com.example.demo.entity.user;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.springframework.transaction.annotation.Transactional;


import java.util.List;

public interface userMapper {

    @Select("Select * from phone")
    List findAll();
//INSERT INTO `phone`(`commodity_Id`, `name`, `price`, `creation_Time`, `picture`, `id`, `commodityType`, `commoditySate`) VALUES (10, '手机01', 2000.00, '2022-03-13 22:20:51', 'http://www.kaotop.com/file/tupian/20220427/s3.bmp.ovh/imgs/2022/03/cb452b6f8d9bef72.jpg', 1, NULL, NULL);
    @Update("INSERT INTO `phone`( `name`, `price`, `creation_Time`, `picture`, `id`, `commodityType`, `commoditySate`) VALUES (#{name},#{price},#{creation_Time},#{picture},#{id},#{commodityType},#{commoditySate});")
    @Transactional
//    事物注解
    void save(user phone);

//UPDATE `ssm_db`.`phone` SET `name` = '手机01', `price` = 2000.00, `creation_Time` = '2022-03-13 22:20:51', `picture` = 'http://www.kaotop.com/file/tupian/20220427/s3.bmp.ovh/imgs/2022/03/cb452b6f8d9bef72.jpg', `id` = 1, `commodityType` = NULL, `commoditySate` = NULL WHERE `commodity_Id` = 10;
    @Update("Update phone SET name = #{name},price = #{price},creation_Time = #{creation_Time}, picture= #{picture},id=#{id},commodityType=#{commodityType},commoditySate = #{commoditySate} WHERE commodity_Id = #{commodity_Id}")
    @Transactional
    void updateById(user phone);
}