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从零开始完成一个SpringBoot+JPA的学生管理系统Web案例((二)后端实现)_助教管理系统的后端编辑

作者：我家小花儿 | 2024-05-26 14:05:37

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助教管理系统的后端编辑

这篇主要展示该案例的后端代码和功能实现，后端实现数据的操作功能后返回Json数组。

(一)目录结构：

(二)后台代码

Entity包

1. User.java

  1. package com.example.stu.kudestu.stu.entity;
  2.  
  3. import javax.persistence.*;
  4.  
  5.  
  6. @Entity
  7. @Table(name = "user")
  8. public class User {
  9.  
  10.  
  11.     @Id
  12.     @GeneratedValue(strategy = GenerationType.IDENTITY) //设置主键自增
  13.     private Integer id;
  14.     private String username;
  15.     private String password;
  16.  
  17.     public User() {
  18.     }
  19.  
  20.     @Override
  21.     public String toString() {
  22.         return "User{" +
  23.                 "id=" + id +
  24.                 ", username='" + username + '\'' +
  25.                 ", password='" + password + '\'' +
  26.                 '}';
  27.     }
  28.  
  29.     public Integer getId() {
  30.         return id;
  31.     }
  32.  
  33.     public void setId(Integer id) {
  34.         this.id = id;
  35.     }
  36.  
  37.     public String getUsername() {
  38.         return username;
  39.     }
  40.  
  41.     public void setUsername(String username) {
  42.         this.username = username;
  43.     }
  44.  
  45.     public String getPassword() {
  46.         return password;
  47.     }
  48.  
  49.     public void setPassword(String password) {
  50.         this.password = password;
  51.     }
  52. }

2. Student.java

  1. package com.example.stu.kudestu.stu.entity;
  2.  
  3. import javax.persistence.*;
  4.  
  5. @Entity
  6. @Table(name = "student")
  7. public class Student {
  8.  
  9.     @Id
  10.     @GeneratedValue(strategy = GenerationType.IDENTITY)
  11.     private Integer id;
  12.     private String name;
  13.     private Integer age;
  14.     private String sex;
  15.  
  16.  
  17.     public Student() {
  18.     }
  19.  
  20.     @Override
  21.     public String toString() {
  22.         return "Student{" +
  23.                 "id=" + id +
  24.                 ", name='" + name + '\'' +
  25.                 ", age=" + age +
  26.                 ", sex='" + sex + '\'' +
  27.                 '}';
  28.     }
  29.  
  30.     public Integer getId() {
  31.         return id;
  32.     }
  33.  
  34.     public void setId(Integer id) {
  35.         this.id = id;
  36.     }
  37.  
  38.     public String getName() {
  39.         return name;
  40.     }
  41.  
  42.     public void setName(String name) {
  43.         this.name = name;
  44.     }
  45.  
  46.     public Integer getAge() {
  47.         return age;
  48.     }
  49.  
  50.     public void setAge(Integer age) {
  51.         this.age = age;
  52.     }
  53.  
  54.     public String getSex() {
  55.         return sex;
  56.     }
  57.  
  58.     public void setSex(String sex) {
  59.         this.sex = sex;
  60.     }
  61. }

Dao包

1. UserDao

  1. package com.example.stu.kudestu.stu.dao;
  2.  
  3. import com.example.stu.kudestu.stu.entity.User;
  4. import org.springframework.data.jpa.repository.JpaRepository;
  5. import org.springframework.data.jpa.repository.Query;
  6. import org.springframework.data.repository.query.Param;
  7.  
  8. public interface UserDao  extends JpaRepository<User,Integer> {
  9.  
  10.     User findUserById(Integer id);
  11.  
  12.     @Query(name="login",nativeQuery = true,value = "select * from user where username=:username and password=:password")
  13.     User login(@Param("username") String username, @Param("password") String password);
  14. }

2. StudentDao

  1. package com.example.stu.kudestu.stu.dao;
  2.  
  3. import com.example.stu.kudestu.stu.entity.Student;
  4. import com.example.stu.kudestu.stu.entity.User;
  5. import org.springframework.data.domain.Page;
  6. import org.springframework.data.jpa.repository.JpaRepository;
  7. import org.springframework.data.jpa.repository.Query;
  8. import org.springframework.data.repository.query.Param;
  9.  
  10. import java.util.List;
  11.  
  12. public interface StudentDao extends JpaRepository<Student,Integer> {
  13.  
  14.     Student findStuById(Integer id);
  15.  
  16.     @Query(name = "findStuByName",nativeQuery = true,value =
  17.             "select * from student where name=:name")
  18.     List<Student> findStuByName(@Param("name") String name);
  19.  
  20. }

Service包

1. UserService 

  1. package com.example.stu.kudestu.stu.service;
  2.  
  3. import com.example.stu.kudestu.stu.entity.User;
  4. import org.springframework.data.domain.Page;
  5.  
  6. import java.util.List;
  7.  
  8. public interface UserService {
  9.  
  10.     List<User> findAll();
  11.  
  12.     User findUserById(int id);
  13.  
  14.     User save(User user);
  15.  
  16.     User update(User user);
  17.  
  18.     void delete(int id );
  19.  
  20.     User login(String username,String password);
  21.  
  22.     Page<User> findByPage(int page, int pagesize);
  23.  
  24. }

2. UserServiceImpl

  1. package com.example.stu.kudestu.stu.service;
  2.  
  3. import com.example.stu.kudestu.stu.dao.UserDao;
  4. import com.example.stu.kudestu.stu.entity.User;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.data.domain.Page;
  7. import org.springframework.data.domain.PageRequest;
  8. import org.springframework.data.domain.Pageable;
  9. import org.springframework.stereotype.Service;
  10.  
  11. import java.util.List;
  12.  
  13. @Service
  14. public class UserServiceImpl implements UserService{
  15.  
  16.  
  17.  
  18.     @Autowired
  19.     UserDao userDao;
  20.  
  21.     @Override
  22.     public List<User> findAll() {
  23.         return userDao.findAll();
  24.     }
  25.  
  26.     @Override
  27.     public User findUserById(int id) {
  28.         return userDao.findUserById(id);
  29.     }
  30.  
  31.  
  32.     @Override
  33.     public User save(User user) {
  34.         return userDao.save(user);
  35.     }
  36.  
  37.     @Override
  38.     public User update(User user) {
  39.         return userDao.save(user);
  40.     }
  41.  
  42.     @Override
  43.     public void delete(int id) {
  44.         userDao.deleteById(id);
  45.     }
  46.  
  47.     @Override
  48.     public User login(String username, String password) {
  49.         return userDao.login(username,password);
  50.     }
  51.  
  52.     @Override
  53.     public Page<User> findByPage(int page, int pagesize) {
  54.         Pageable pageable = PageRequest.of(page,pagesize);
  55.         return userDao.findAll(pageable);
  56.     }
  57. }

3. StudentService

  1. package com.example.stu.kudestu.stu.service;
  2.  
  3. import com.example.stu.kudestu.stu.entity.Student;
  4. import org.springframework.data.domain.Page;
  5.  
  6. import java.util.List;
  7.  
  8. public interface StudentService {
  9.  
  10.     //保存
  11.     Student save(Student student);
  12.     //修改
  13.     Student update(Student student);
  14.     //删除
  15.     void delete(Integer id);
  16.     //根据id查询
  17.     Student findStuById(Integer id);
  18.     //根据名字查询
  19.     List<Student> fingStuByName(String name);
  20.  
  21.     /**
  22.      * 分页查询所有
  23.      * @param page
  24.      * @param pagesize
  25.      * @return
  26.      */
  27.     Page<Student> findAll(int page,int pagesize);
  28.  
  29. }

4. StudentServiceImol

  1. package com.example.stu.kudestu.stu.service;
  2.  
  3. import com.example.stu.kudestu.stu.dao.StudentDao;
  4. import com.example.stu.kudestu.stu.entity.Student;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.data.domain.Page;
  7. import org.springframework.data.domain.PageRequest;
  8. import org.springframework.data.domain.Pageable;
  9. import org.springframework.stereotype.Service;
  10.  
  11. import java.util.List;
  12.  
  13. @Service
  14. public class StudentServiceImpl  implements StudentService{
  15.  
  16.     @Autowired
  17.     StudentDao studentDao;
  18.  
  19.     @Override
  20.     public Student save(Student student) {
  21.         return studentDao.save(student);
  22.     }
  23.  
  24.     @Override
  25.     public Student update(Student student) {
  26.         return studentDao.save(student);
  27.     }
  28.  
  29.     @Override
  30.     public void delete(Integer id) {
  31.         studentDao.deleteById(id);
  32.     }
  33.  
  34.     @Override
  35.     public Student findStuById(Integer id) {
  36.         return studentDao.findStuById(id);
  37.     }
  38.  
  39.     @Override
  40.     public List<Student> fingStuByName(String name) {
  41.         return studentDao.findStuByName(name);
  42.     }
  43.  
  44.     @Override
  45.     public Page<Student> findAll(int page, int pagesize) {
  46.         Pageable pageable = PageRequest.of(page,pagesize);
  47.         return studentDao.findAll(pageable);
  48.     }
  49. }

Controller包

1. UserController

  1. package com.example.stu.kudestu.stu.controller;
  2.  
  3.  
  4. import com.example.stu.kudestu.stu.entity.User;
  5. import com.example.stu.kudestu.stu.service.UserService;
  6. import org.springframework.beans.factory.annotation.Autowired;
  7. import org.springframework.data.domain.Page;
  8. import org.springframework.web.bind.annotation.GetMapping;
  9. import org.springframework.web.bind.annotation.RequestMapping;
  10. import org.springframework.web.bind.annotation.RequestMethod;
  11. import org.springframework.web.bind.annotation.RestController;
  12.  
  13. import javax.servlet.http.HttpServletResponse;
  14. import java.util.List;
  15.  
  16.  
  17. @RestController
  18. @RequestMapping("/user")
  19. public class UserController {
  20.  
  21.     @Autowired
  22.     private UserService userService;
  23.  
  24.     /**
  25.      * 查询所有用户
  26.      * @return
  27.      */
  28.     @RequestMapping("/findAll")
  29.     public List<User> findAll(){
  30.  
  31.         return userService.findAll();
  32.     }
  33.  
  34.     /**
  35.      * 根据id查找用户
  36.      * @param id
  37.      * @return
  38.      */
  39.     @RequestMapping("/findById")
  40.     public User findById(int id){
  41.         return userService.findUserById(id);
  42.     }
  43.  
  44.     /**
  45.      * 用户注册
  46.      * @param user
  47.      * @return
  48.      */
  49.     @RequestMapping(value = "/reg",method = RequestMethod.POST)
  50.     public User reg(User user){
  51.  
  52.         return userService.save(user);
  53.     }
  54.  
  55.     /**
  56.      * 用户登录
  57.      * @param username
  58.      * @param password
  59.      * @return
  60.      */
  61.     @RequestMapping(value = "/login",method = RequestMethod.POST)
  62.     public User login(String username,String password){
  63.         return userService.login(username,password);
  64.     }
  65.  
  66.     /**
  67.      * 用户修改
  68.      * @param user
  69.      * @return
  70.      */
  71.     @RequestMapping(value = "/update",method = RequestMethod.POST)
  72.     public User update(User user){
  73.         return userService.save(user);
  74.     }
  75.  
  76.     /**
  77.      * 用户删除
  78.      * @param id
  79.      */
  80.     @RequestMapping("/delete")
  81.     public void delete(int id){
  82.         userService.delete(id);
  83.     }
  84.     
  85.     /**
  86.      * 分页查询
  87.      * @param page
  88.      * @param response
  89.      * @return
  90.      */
  91.     @RequestMapping("/page")
  92.     public Page<User> findByPage(Integer page, HttpServletResponse response){
  93.  
  94.         //解决跨域请求
  95.         response.setHeader("Access-Control-Allow-Origin","*");
  96.  
  97.         if(page==null || page<=0){
  98.             page = 0;
  99.         }else{
  100.             page -= 1;
  101.         }
  102.  
  103.         return userService.findByPage(page,5);
  104.  
  105.     }
  106.  
  107. }

2. StudentController

  1. package com.example.stu.kudestu.stu.controller;
  2.  
  3.  
  4. import com.example.stu.kudestu.stu.entity.Student;
  5. import com.example.stu.kudestu.stu.service.StudentService;
  6. import org.springframework.beans.factory.annotation.Autowired;
  7. import org.springframework.data.domain.Page;
  8. import org.springframework.web.bind.annotation.*;
  9.  
  10. import javax.servlet.http.HttpServletResponse;
  11. import java.util.List;
  12.  
  13. @RestController
  14. @RequestMapping("/stu")
  15. public class StudentController {
  16.  
  17.     @Autowired
  18.     StudentService studentService;
  19.  
  20.     @PostMapping("/add")
  21.     public Student save(Student student){
  22.         return studentService.save(student);
  23.     }
  24.  
  25.     @PostMapping("/update")
  26.     public Student update(Student student){
  27.         return studentService.save(student);
  28.     }
  29.  
  30.     @GetMapping("/delete/{id}")
  31.     public String delete(@PathVariable int id){
  32.         studentService.delete(id);
  33.         return "delete success";
  34.     }
  35.  
  36.  
  37.     @GetMapping("/findById")
  38.     public Student findById(int id){
  39.         return studentService.findStuById(id);
  40.     }
  41.  
  42.     @GetMapping("/findByName/{name}")
  43.     public List<Student> findByName(@PathVariable String name){
  44.  
  45.         return studentService.fingStuByName(name);
  46.     }
  47.  
  48.     @GetMapping("/query")
  49.     public Page<Student> findByPage(Integer page, HttpServletResponse response){
  50.  
  51.         //解决跨域请求
  52.         response.setHeader("Access-Control-Allow-Origin","*");
  53.  
  54.         if(page==null || page<=0){
  55.             page = 0;
  56.         }else{
  57.             page -= 1;
  58.         }
  59.  
  60.         return studentService.findAll(page,5);
  61.  
  62.     }
  63.  
  64.  
  65.  
  66.  
  67. }

(三)测试

这里使用Postman来测试（前后端分离为了测试Post请求和查看Json数据）下载Postman百度云盘链接  提取码：qe9r 

测试StudentControllar，功能已经全部实现和测试过了，下面选一些来展示。下面是一些请求Mapping：

  1. //学生注册
  2. @PostMapping("/add") 
  3. //学生修改
  4. @PostMapping("/update")
  5. //学生删除
  6. @GetMapping("/delete/{id}")
  7. //根据Id查找学生
  8. @GetMapping("/findById")
  9. //根据姓名查找学生
  10. @GetMapping("/findByName/{name}")
  11. //分页查询所有
  12. @GetMapping("/query")

1. 测试注册

地址栏输入 http://localhost:8888/kude/stu/add 然后在下面添加参数后点击Send

添加后数据库信息：

2. 测试修改

成功后返回结果

3. 分页查询所有数据

此时表中共有14条数据，按照设定的一页五条数据的话，一共能分为三页。

输入请求地址

返回的所有Json数据如下：

  1. {
  2.     "content": [
  3.         {
  4.             "id": 1,
  5.             "name": "杜炮",
  6.             "age": 20,
  7.             "sex": "男"
  8.         },
  9.         {
  10.             "id": 2,
  11.             "name": "Lux",
  12.             "age": 16,
  13.             "sex": "女"
  14.         },
  15.         {
  16.             "id": 3,
  17.             "name": "Lux",
  18.             "age": 17,
  19.             "sex": "女"
  20.         },
  21.         {
  22.             "id": 4,
  23.             "name": "Lux",
  24.             "age": 18,
  25.             "sex": "女"
  26.         },
  27.         {
  28.             "id": 5,
  29.             "name": "Klua",
  30.             "age": 20,
  31.             "sex": "男"
  32.         }
  33.     ],
  34.     "pageable": {
  35.         "sort": {
  36.             "sorted": false,
  37.             "unsorted": true,
  38.             "empty": true
  39.         },
  40.         "offset": 0,
  41.         "pageNumber": 0,
  42.         "pageSize": 5,
  43.         "unpaged": false,
  44.         "paged": true
  45.     },
  46.     "totalPages": 3,      //分页数
  47.     "totalElements": 14,  //数据总条数
  48.     "last": false,
  49.     "number": 0,          //当前页数（从零开始）0就是第一页
  50.     "size": 5,            //分页大小
  51.     "sort": {
  52.         "sorted": false,
  53.         "unsorted": true,
  54.         "empty": true
  55.     },
  56.     "numberOfElements": 5,  //该页的数据条数
  57.     "first": true,
  58.     "empty": false
  59. }

测试完成，接下来编写前台代码，前后端链接再进行测试，请看下一篇：《从零开始完成一个SpringBoot+JPA的Web案例((三)前端实现)》 

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