springboot写一个简单的增删改后台接口（jpa）

bean实体类：

package com.spring.comtroller.demo.bean;

import javax.persistence.*;
import java.io.Serializable;

@Entity
@Table(name="user", schema = "myapp")
public class Student implements Serializable{
    @Id
    @GeneratedValue
    @Column(name="id")
    private long id;
    @Column(name = "name")
    private String name;

    public Student() {
    }

    public Student(long id, String name) {
        this.id = id;
        this.name = name;
    }

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

　　controller控制类：

package com.spring.comtroller.demo.controller;

import com.spring.comtroller.demo.bean.Student;
import com.spring.comtroller.demo.result.ResultModel;
import com.spring.comtroller.demo.result.ResultModelTool;
import com.spring.comtroller.demo.service.IStudent;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping(value = "/students")
public class StudentController {

    @Autowired
    IStudent studentService;

    @RequestMapping(value = "/all",method = RequestMethod.GET)
    public ResultModel getAllStudent(){
        List<Student> studentList = studentService.getAllStudent();
        Map<String,List<Student>> studentMap = new HashMap<>();
        if (studentList!=null){
            studentMap.put("students",studentList);
        }
        ResultModel resultModel = new ResultModel();
        resultModel.setCode(0);
        resultModel.setData(studentMap);
        return ResultModelTool.handleResultModel(resultModel);
    }

    @PostMapping(value = "/addStudent")
    public ResultModel addStudent(@RequestParam long id,@RequestParam String name){
        Student student = new Student(id,name);
        int errorCode = studentService.addStudent(student);
        ResultModel resultModel = new ResultModel();
        resultModel.setCode(errorCode);
        resultModel.setData(student);
        return ResultModelTool.handleResultModel(resultModel);
    }

    @PostMapping(value = "/updateStudent")
    public ResultModel updateStudent(@RequestParam long id,@RequestParam String name){
        Student student = new Student(id,name);
        int errorCode = studentService.updateStudent(student);
        ResultModel resultModel = new ResultModel();
        resultModel.setCode(errorCode);
        resultModel.setData(student);
        return ResultModelTool.handleResultModel(resultModel);
    }
    @GetMapping(value = "/deleteStudent/{id}")
    public ResultModel deleteStudent(@PathVariable long id){
        int errorCode = studentService.deleteStudent(id);
        ResultModel resultModel = new ResultModel();
        resultModel.setCode(errorCode);
        List<Student> studentList = studentService.getAllStudent();
        Map<String,List<Student>> studentMap = new HashMap<>();
        if (studentList!=null){
            studentMap.put("students",studentList);
        }
        resultModel.setData(studentMap);
        return ResultModelTool.handleResultModel(resultModel);
    }
}

　　respository层：

public interface JpaStudentRepository extends JpaRepository<Student,Long>{

}
public interface StudentRepository extends Repository<Student,Long> {

}

　　service层：

public interface IStudent {
    //获取所有的学生
    List<Student> getAllStudent();
    //增
    int  addStudent(Student student);
    //删
    int  deleteStudent(long id);
    //改
    int updateStudent(Student student);
    //查
    Student queryStudent(long id);
}

　　service实现类：

package com.spring.comtroller.demo.service;

import com.spring.comtroller.demo.bean.Student;
import com.spring.comtroller.demo.repository.JpaStudentRepository;
import com.spring.comtroller.demo.result.ErrorCode;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class StudentImpl implements IStudent {
    @Autowired
    JpaStudentRepository jpaStudentRepository;

    @Override
    public List<Student> getAllStudent() {
        List<Student> students = jpaStudentRepository.findAll();
        System.out.println(students.toString());
        return students;
    }

    @Override
    public int addStudent(Student student) {
        if (jpaStudentRepository.existsById(student.getId())){
            System.out.println("user  is existed");
            return ErrorCode.EXISTUSER;
        }
        Student saveStudent = jpaStudentRepository.save(student);
        if (saveStudent != null && saveStudent.getId() == student.getId()) {
            System.out.println("save success");
            return ErrorCode.ADDSUCCESS;
        } else {
            System.out.println("save failure");
            return ErrorCode.ADDFAIL;
        }
    }

    @Override
    public int deleteStudent(long id) {
        if (jpaStudentRepository.existsById(id)) {
            jpaStudentRepository.deleteById(id);
            System.out.println("删除成功");
            return ErrorCode.DELETESUCCESS;
        }
        System.out.println("删除失败");
        return ErrorCode.NOTEXISTUSER;
    }

    @Override
    public int updateStudent(Student student) {
        if (jpaStudentRepository.existsById(student.getId())){
            jpaStudentRepository.save(student);
            System.out.println("更新成功");
            return ErrorCode.UPDATESUCCESS;
        }
        System.out.println("更新失败");
        return ErrorCode.UPDATEFAIL;
    }

    @Override
    public Student queryStudent(long id) {
        Student student = null;
        if (jpaStudentRepository.existsById(id)){
            student = jpaStudentRepository.findById(id).get();
            System.out.println(student.toString());
        }
        return student;
    }
}

　　result类：

public interface ErrorCode {
    /**
     * 10000 网络繁忙
     * 10001 无此用户
     * 10002 添加成功
     * 10003 删除成功
     * 10004 更新成功
     * 10005 此用户已存在
     * 10006 添加失败
     * 10007 删除失败
     * 10008 更新失败
     * -1 请求失败
     * 0 请求成功
     */

    int NETERROR = 10000;
    int NOTEXISTUSER = 10001;
    int ADDSUCCESS = 10002;
    int DELETESUCCESS = 10003;
    int UPDATESUCCESS = 10004;
    int EXISTUSER = 10005;
    int ADDFAIL = 10006;
    int DELETEFAIL = 10007;
    int UPDATEFAIL = 10008;
    int REQUESTFAIL = -1;
    int REQUESTSUCCESS = 0;
}

　　

public class ResultModel implements Serializable{
    private int code;
    private String msg;
    private Object data ;

    public ResultModel() {

    }

    public ResultModel(int errorCode, String msg, Object data) {
        this.code = errorCode;
        this.msg = msg;
        this.data = data;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

　　

package com.spring.comtroller.demo.result;

import java.util.HashMap;
import java.util.Map;

public class ResultModelTool {

    public static ResultModel handleResultModel(ResultModel resultModel) {

        ResultModel handledModel = new ResultModel();
        Map map = new HashMap();
        if (resultModel != null) {
            int error = resultModel.getCode();
            handledModel.setCode(error);
            switch (error) {
                case 10000:
                    handledModel.setMsg("网络繁忙,请稍后重试");
                    handledModel.setData(map);
                    break;
                case 10001:
                    handledModel.setMsg("无此用户");
                    handledModel.setData(map);
                    break;
                case 10002:
                    handledModel.setMsg("添加成功");
                    handledModel.setData(resultModel.getData());
                    break;
                case 10003:
                    handledModel.setMsg("删除成功");
                    handledModel.setData(resultModel.getData());
                    break;
                case 10004:
                    handledModel.setMsg("更新成功");
                    handledModel.setData(resultModel.getData());
                    break;
                case -1:
                    handledModel.setMsg("请求失败");
                    handledModel.setData(map);
                    break;
                case 10005:
                    handledModel.setMsg("此用户已存在");
                    handledModel.setData(map);
                    break;
                case 10006:
                    handledModel.setMsg("添加失败");
                    handledModel.setData(map);
                    break;
                case 10007:
                    handledModel.setMsg("删除失败");
                    handledModel.setData(map);
                    break;
                case 10008:
                    handledModel.setMsg("更新失败");
                    handledModel.setData(map);
                    break;
                default:
                    handledModel.setMsg("请求成功");
                    handledModel.setData(resultModel.getData());
                    break;
            }
        }
        return handledModel;
    }
}