DELETE方法无法正确删除实体

Question

I'm trying to delete an object that I get by using JSON through a POST request. Then by using the objects id, I want to delete it using a DELETE request. The DELETE request responds back with a 204 No Content .

That's all good but when I use the GET request to get all existing objects, the object that was deleted is still there.

I delete the object by including its id as a @PathParam() .

I have tested the operation just using plain Java and it works fine.

DatabaseClass.java

public class DatabaseClass {

    private static Map<Integer, Message> messages = new HashMap<>();
    private static Map<String, Profile> profiles = new HashMap<>();

    public static Map<Integer, Message> getAllMessages() {
        return messages;
    }

    public static Map<String, Profile> getAllProfiles() {
        return profiles;
    }
}

Message.java

@XmlRootElement
public class Message {

    private Integer id;
    private String author;
    private String text;
    private Date dateCreated;

    public Message() {}

    public Message(String author, String text) {
        this.author = author;
        this.text = text;
        this.dateCreated = new Date();
    }

    public Integer getId() {
        return id;
    }

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

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public Date getDateCreated() {
        return dateCreated;
    }

    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("ID: " + id + "\n");
        sb.append("Author: " + author + "\n");
        sb.append("Text: " + text + "\n");
        sb.append("Date Created: " + dateCreated + "\n\n");

        return sb.toString();
    }
}

MessageService.java

public class MessageService {

    private Map<Integer, Message> messages = DatabaseClass.getAllMessages();

    public MessageService() {}

    public List<Message> getMessages() {
        return new ArrayList<>(messages.values());
    }

    public Message getMessage(Integer id) {
        if(!messages.containsKey(id)) {
            throw new NotFoundException("Message was not found.");
        }

        return messages.get(id);
    }

    public Message addMessage(Message message) {
        message.setId(messages.size() + 1);
        message.setDateCreated(new Date());

        messages.put(message.getId(), message);

        return messages.get(message.getId());
    }

    public Message updateMessage(Message message) {
        if(message.getId() <= 0) { 
            return null;
        }
        messages.put(message.getId(), message);

        return messages.get(message.getId());
    }

    public Message deleteMessage(Integer id) {
        return messages.remove(id);
    }
}

MessageResource.java

@Path("messages")
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public class MessageResource {

    private MessageService mService = new MessageService();

    @POST
    public Message addMessage(Message message) {
        return mService.addMessage(message);
    }

    @GET
    public List<Message> getMessages() {
        return mService.getMessages();
    }

    @GET
    @Path("{messageId}")
    public Message getMessage(@PathParam("messageId") Integer messageId) {
        return mService.getMessage(messageId);
    }

    @PUT
    @Path("{messageId}")
    public Message updateMessage(@PathParam("messageId") Integer messageId, 
            Message message) {
        return mService.updateMessage(message);
    }

    @DELETE
    @Path("{messagesId}")
    public Message deleteMessage(@PathParam("messageId") Integer messageId) {
        return mService.deleteMessage(messageId);
    }
}

I also have another question on here and it contains another object called Profile . The ProfileResource.java class has the POST, PUT, GET, and DELETE methods. If I deleted a profile the response I get back is 200 OK and not 204 No Content which I find very weird because I should be getting a 204 No Content . Either way the profile gets deleted successfully.

Answer 1

Because MessageService is being created every request which calls the constructor in resources.

private MessageService mService = new MessageService();

If you create a new message using POST and DELETE, the same will work.