java - 学生编辑不行(Java + Spring + MySQl)？

Question

我有一份学生名单。我想做编辑。更改名字、姓氏和头像。我写了代码，但它不起作用，数据没有被编辑。你可以明白为什么它对我不起作用。没有错误，它只是没有改变任何东西。编辑名字后姓氏和头像不变

学生服务

public interface StudentService {

    List<Student> getAllStudents();

    Student getStudentById(Long id);

    boolean saveStudent(Student student);

    boolean deleteStudentById(Long id);

    File loadAvatarByFileName(String filename);

    File saveAvatarImage(MultipartFile avatarImage) throws IOException;

        Student updateStudent(String name, String surname, MultipartFile avatar, Student targetStudent) throws IOException;
}

学生服务实现

@Service
@Transactional
public class StudentServiceImpl implements StudentService {

    @Value("${storage.location}")

    private String storageLocation;

    private StudentRepository repository;

    public StudentServiceImpl() {

    }

    @Autowired
    public StudentServiceImpl(StudentRepository repository) {
        super();
        this.repository = repository;
    }

    @Override
    public List<Student> getAllStudents() {
        List<Student> list = new ArrayList<Student>();
        repository.findAll().forEach(e -> list.add(e));
        return list;
    }

    @Override
    public Student getStudentById(Long id) {
        Student student = repository.findById(id).get();
        return student;
    }

    @Override
    public boolean saveStudent(Student student) {
        try {
            repository.save(student);
            return true;
        } catch (Exception ex) {
            return false;
        }
    }

    @Override
    public boolean deleteStudentById(Long id) {
        try {
            repository.deleteById(id);
            return true;
        } catch (Exception ex) {
            return false;
        }

    }

    @Override

    public File loadAvatarByFileName(String filename) {

        return new File(storageLocation + "/" + filename);

    }

    @Override


    public File saveAvatarImage(MultipartFile avatarImage) throws IOException {

        File newFile = File.createTempFile(
                avatarImage.getName(),
                "." + avatarImage.getOriginalFilename().split("\\.")[1],

                new File(storageLocation));

        avatarImage.transferTo(newFile);

        return newFile;

    }

    @Override

    public Student updateStudent(String name, String surname, MultipartFile avatar, Student targetStudent)

           throws IOException {

        if (name != null && !name.equals(targetStudent.getName())) {

            targetStudent.setName(name);

        }

        if (surname != null && !surname.equals(targetStudent.getSurname())) {

            targetStudent.setSurname(surname);

        }

        String oldAvatarName = targetStudent.getAvatar();

        if (oldAvatarName != null) {
            Files.deleteIfExists(Paths.get(storageLocation + File.separator + oldAvatarName));
        }

        File newAvatar = null;
        if (avatar != null) {
            newAvatar = saveAvatarImage(avatar);
            assert newAvatar != null;
            targetStudent.setAvatar(newAvatar.getName());
        }

       boolean isSaved = saveStudent(targetStudent);

        if (!isSaved) {

            throw new IOException();

        }

        Files.deleteIfExists(Paths.get(storageLocation + File.separator + oldAvatarName));

        return targetStudent;

    }

学生 Controller

package adil.java.schoolmaven.controller;

import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletContext;
import adil.java.schoolmaven.entity.Student;
import adil.java.schoolmaven.service.StudentService;
import java.nio.file.FileSystemException;
import javax.servlet.http.HttpServletRequest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.lang.NonNull;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class StudentController {

    @Autowired
    private ServletContext servletContext;

    // Constructor based Dependency Injection
    private StudentService studentService;

    public StudentController() {

    }

    @Autowired
    public StudentController(StudentService studentService) {
        this.studentService = studentService;
    }

    @RequestMapping(value = "/allStudents",  method = {RequestMethod.GET, RequestMethod.POST})

    public ModelAndView displayAllUser() {
        System.out.println("User Page Requested : All Students");
        ModelAndView mv = new ModelAndView();
        List<Student> studentList = studentService.getAllStudents();
        mv.addObject("studentList", studentList);
        mv.setViewName("allStudents");
        return mv;
    }



    @RequestMapping(value = "/addStudent", method = RequestMethod.GET)
    public ModelAndView displayNewUserForm() {
        ModelAndView mv = new ModelAndView("addStudent");
        mv.addObject("headerMessage", "Add Student Details");
        mv.addObject("student", new Student());
        return mv;
    }

    @PostMapping(value = "/addStudent")
    public String saveNewStudent(@RequestParam("name") @NonNull String name,
            @RequestParam("surname") @NonNull String surname,
            @RequestParam("avatar") MultipartFile file)
            throws IOException {

        Student student = new Student();
        student.setSurname(surname);
        student.setName(name);

        if (file != null && !file.isEmpty()) {
            student.setAvatar(studentService.saveAvatarImage(file).getName());
        }

        studentService.saveStudent(student);
        return "redirect:/allStudents";
    }

    @GetMapping(value = "/editStudent/{id}")
    public ModelAndView displayEditUserForm(@PathVariable Long id) {
        ModelAndView mv = new ModelAndView("editStudent");
        Student student = studentService.getStudentById(id);
        mv.addObject("headerMessage", "Редактирование студента");
        mv.addObject("student", student);
        return mv;
    }

    @PostMapping(value = "/editStudent")
    public String saveEditedUser(
            @RequestParam("id") Long id,
            @RequestParam("name") String name,
            @RequestParam("surname") String surname,
            @RequestParam("avatar") MultipartFile file) {

        try {

            studentService.updateStudent(name, surname, file, studentService.getStudentById(id));

        } catch (FileSystemException ex) {
            ex.printStackTrace();
        } catch (IOException e) {
            return "redirect:/error";
        }

        return "redirect:/allStudents";
    }

    @GetMapping(value = "/deleteStudent/{id}")
    public ModelAndView deleteUserById(@PathVariable Long id) {
        studentService.deleteStudentById(id);
        ModelAndView mv = new ModelAndView("redirect:/allStudents");

        return mv;

    }

}

编辑学生 JSP

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/css/bootstrap.min.css">
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
        <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/js/bootstrap.min.js"></script>

        <title>Home</title>
    </head>
    <body>

        <center>
                <h1>${headerMessage}</h1>


                <form:form method="POST" action="${pageContext.request.contextPath}/editStudent" enctype="multipart/form-data">
                    <table>
                        <input type="hidden" value="${student.id}" name="id"/>
                        <tr>

                            <td><label path="Name">Name</label></td>
                            <td><input type="text" name="name" value="${student.name}"/></td>
                        </tr>
                        <tr>
                            <td><label path="Surname">Surname</label></td>
                            <td><input name="surname" value="${student.surname}"/></td>
                        </tr>
                        <tr>
                            <td><label path="Avatar">Avatar:</label></td>
                            <td>
                                <img src="${pageContext.request.contextPath}/avatar?avatar=${student.avatar}"
                                     style="max-height: 200px; max-width: 200px;"/>
                            </td>
                            <td>
                                <input type="file" name="avatar"/>
                            </td>
                        </tr>
                        <tr>
                            <td><input class="btn btn-primary" type="submit" value="Save"></td>
                        </tr>
                    </table>
                </form:form>
        </center>
    </body>
</html>

我的日志

(根据谷歌翻译，错误消息翻译为“该进程无法访问该文件，因为该文件正在被另一个进程使用。”)

java.nio.file.FileSystemException: C:\Pictures\avatar3435295369309803118.jpg: Процесс не может получить доступ к файлу, так как этот файл занят другим процессом.

    at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:86)
    at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
    at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
    at sun.nio.fs.WindowsFileSystemProvider.implDelete(WindowsFileSystemProvider.java:269)
    at sun.nio.fs.AbstractFileSystemProvider.deleteIfExists(AbstractFileSystemProvider.java:108)
    at java.nio.file.Files.deleteIfExists(Files.java:1165)
    at adil.java.schoolmaven.service.StudentServiceImpl.updateStudent(StudentServiceImpl.java:122)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:338)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:197)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
    at com.sun.proxy.$Proxy402.updateStudent(Unknown Source)
    at adil.java.schoolmaven.controller.StudentController.saveEditedUser(StudentController.java:98)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.bufferAndPostProcess(ContentBufferingFilter.java:169)
    at org.sitemesh.webapp.contentfilter.ContentBufferingFilter.doFilter(ContentBufferingFilter.java:126)
Hibernate: 
    select

Answer 1

该错误表明另一个进程正在使用该文件，因此无法删除该文件。

您是否在另一个程序中打开了给定的文件？

当您尝试删除文件时，您的代码是否会打开该文件/使其在其他位置保持打开状态？

我看到您的 StudentServiceImpl.updateStudent 正在调用 Files.deleteIfExists(Paths.get(storageLocation + File.separator + oldAvatarName)); 两次。根据堆栈跟踪，有问题的行是 StudentServiceImpl.java:122。两行中哪一行的数字是 122？