如何更新 spring 启动应用程序中的记录？

Question

我正在尝试更新 spring 启动应用程序中的记录，但它添加了新记录而不是更新，我也想搜索

import java.sql.Timestamp;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Transient;

@Entity

public class Events {
    
private Long id;

private String game;

private String catergory;

private String venue;

private float entrance_fee;

private String date;

private String time;

private Timestamp created_time;


private String image;

public Events() {

    super();

    // TODO Auto-generated constructor stub
}



@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

public Long getId() {

    return id;
}

public void setId(Long id) {

    this.id = id;
}

public String getGame() {

    return game;
}

public void setGame(String game) {

    this.game = game;
}


public String getCatergory() {

    return catergory;
}

public void setCatergory(String catergory) {

    this.catergory = catergory;
}

public String getVenue() {

    return venue;
}

public void setVenue(String venue) {

    this.venue = venue;
}

public float getEntrance_fee() {

    return entrance_fee;
}

public void setEntrance_fee(float entrance_fee) {

    this.entrance_fee = entrance_fee;
}

public String getDate() {

    return date;
}

public void setDate(String date) {

    this.date = date;
}

public String getTime() {

    return time;
}

public void setTime(String time) {

    this.time = time;
}

public Timestamp getCreated_time() {

    return created_time;
}

public void setCreated_time(Timestamp created_time) {

    this.created_time = created_time;
}

public String getImage() {

    return image;
}

public void setImage(String image) {

    this.image = image;
}


@Transient

public String getImagePath() {

    if(image == null || id == null) return null;
    
    return "/event-images/" + id + "/" + image;
}

}

这是我的存储库...

import java.util.List;

import org.springframework.data.repository.PagingAndSortingRepository;

import org.springframework.stereotype.Repository;


@Repository

    public interface EventsRepository extends PagingAndSortingRepository<Events, Long> {
    
        List<Events> findByCatergoryLike(String catergory);
        
        
    
    }

这是我的服务..

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.data.domain.Page;

import org.springframework.data.domain.PageRequest;

import org.springframework.data.domain.Pageable;

import org.springframework.data.domain.Sort;

import org.springframework.stereotype.Service;


@Service

public class EventsService {

@Autowired

private EventsRepository eventsRepository;

public Page<Events> listAll(int pageNumber){

    Sort sort = Sort.by("date").ascending();

    Pageable pageable = PageRequest.of(pageNumber -1, 1, sort);

    return eventsRepository.findAll(pageable);  
}


public Events save(Events events) {

     return eventsRepository.save(events);
}

public void update(Events events) {

     eventsRepository.save(events);
}

public Events get(Long id) {

    return eventsRepository.findById(id).get();
}


public void delete(Long id) {

    eventsRepository.deleteById(id);
}

public List<Events> findBycatergory(String catergory) {
    
    return eventsRepository.findByCatergoryLike("%"+catergory+"%");
}



}

这是controller中的更新方法..

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

public String upadate(@ModelAttribute("events") @PathVariable(name="id") Long id, Events events,

        @RequestParam("fileImage") MultipartFile multipartFile) throws IOException {

    String fileName = StringUtils.cleanPath(multipartFile.getOriginalFilename());

    events.setImage(fileName);

    eventsService.update(events);

    String uploadDir = "./event-images/" + events.getId();

    Path uploadPath = Paths.get(uploadDir);

    if(!Files.exists(uploadPath)) {

        Files.createDirectories(uploadPath);
    }
    
    try (InputStream inputStream = multipartFile.getInputStream()){


    Path filePath = uploadPath.resolve(fileName);

    Files.copy(inputStream, filePath, StandardCopyOption.REPLACE_EXISTING);



    }catch (IOException e) {

        throw new IOException("Could not save uploaded file: " + fileName);
    }



    if(fileName.length()>1048576) {

        System.out.println("file too large");
    }
    return "redirect:/events";
    
}

然后最后更新表格..

<form action="#" th:action="@{/update_event}" th:object="${Edit_events}" method="post" 

enctype="multipart/form-data">
            
            <div id="name">


            <h2 class="name">Sports</h2>

                <input class="firstname" type="text" th:field="*{game}" /><br>
                                
                 <input class="lastname" type="text" th:field="*{catergory}" /><br>
                
                </div>

            <h2 class="name">Venue</h2>

            <input  class="username" type="text" th:field="*{venue}" />
            
            <h2 class="name">Entrance Fee</h2>

            <input class="email" type="text" th:field="*{entrance_fee}" />
            
            <h2 class="name">Date & Time</h2>


            <input type="date" class="password" th:field="*{date}" />
           
            
             <input  type="time" class="number" th:field="*{time}" /><br>
           

                
             <img th:src="*{imagePath}">



             <input type="file" class="photoBtn" name="fileImage" id="fileImage" accept="image/png, 



image/jpeg"/> <button type="submit">SAVE CHANGES</button><a th:href="@{/events}">..DISCARD..</a>


           
        </form>

Answer 1

解决方案非常简单，您需要先获取记录，然后使用 save(events) 对其进行更新 例如：在请求有效负载中，您将获得事件 class 的 object，使用eventsRepository.findById(events.id) Z9CE3D1Z48 call to fetch the repository tofetch the repository tofetch数据然后更新返回的实例然后保存它，内部 JPA 检查条目是否已注册。 如果是，那么它将更新，否则它将创建一个新条目。

` Optinal<Events>currentEvent = eventsRepository.findById(events.id); if(currentEvent.isPresent()){// map the input values with currentEventusing mapper  eventsRepository.save(events) }`

希望这有帮助