1. 创建springboot项目

2.修改pom.xml

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
    <version>3.5.12</version>
</dependency>

3.项目配置 application.yml

server:
  port: 8888  # 服务器端口号

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db?characterEncoding=utf8&serverTimezone=GMT%2B8
    username: root
    password: root

4. 新建包,如下:

5.修改DemoApplication主启动类

增加注解

@MapperScan("cn.edu.ccrw.demo.mapper")

5.新建PO类

Student

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;
//po类作用是封装数据,与数据库的表对应
//po类需要定义私有属性(与表中的列对应)
//po类需要定义get/set方法
@Data //自动生成 get/set
public class Student  {
    @TableId(type = IdType.AUTO)
    private Integer sno;
    private String  name;
    private String  gender;
    private Integer age;
    private Double  height;
    
}

6.新建Mapper接口

StudentMapper

import cn.edu.ccrw.demo.po.Student;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

//继承 BaseMapper 会根据 Student类结构
//自动生成 sql语句
public interface StudentMapper extends BaseMapper<Student> {
}

7.新建Service接口及实现类
StudentService StudentServiceImpl

import cn.edu.ccrw.demo.po.Student;
import java.util.List;

public interface StudentService {

    String addStudent(Student student);
    String removeStudent(int sno);
    String updateStudent(Student student);
    List<Student> queryAllStudent();
}

import cn.edu.ccrw.demo.mapper.StudentMapper;
import cn.edu.ccrw.demo.po.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper mapper;//业务类依赖 mapper

    @Override
    public String addStudent(Student student) {
        return mapper.insert(student)==1?"增加学生成功":"增加学生失败";
    }

    @Override
    public String removeStudent(int sno) {
        return mapper.deleteById(sno)==1?"删除学生成功":"删除学生失败";
    }

    @Override
    public String updateStudent(Student student) {
        return mapper.updateById(student)==1?"修改学生成功":"修改学生失败";
    }

    @Override
    public List<Student> queryAllStudent() {
        return mapper.selectList(null);
    }
}

8.新建Controller

StudentController

import cn.edu.ccrw.demo.po.Student;
import cn.edu.ccrw.demo.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;

@RestController
@RequestMapping("/student")
public class StudentController {
    @Autowired
    private StudentService service = null; //依赖

    @GetMapping //查询所有数据请求
    public List<Student> queryAll() {
        return service.queryAllStudent();
    }

    @PostMapping //增加数据请求
    public String add(@RequestBody Student student) {
        return  service.addStudent(student);
    }

    @PutMapping //修改数据请求
    public String update(@RequestBody Student student) {
        return service.updateStudent(student);
    }

    @DeleteMapping("/{sno}")   //删除数据请求
    public String delete(@PathVariable("sno") int sno  ) {
        return service.removeStudent(sno);
    }

}