引起原因：com.mongodb.MongoWriteException：E11000重复键错误集合：ChatBox.chat_collection索引：_id_ dup键：{_id：0}

Question

我正在使用Spring Boot，Websockets开发一个聊天框应用程序，并尝试保存在mongoDB数据库中。应用程序运行成功！但是通过将错误作为主键异常抛出，聊天记录未存储在数据库中。我不知道为什么会这样。

这部分属于配置类，其中该类的配置为dong：

@Configuration
@EnableWebSocketMessageBroker
public class WsConfig implements WebSocketMessageBrokerConfigurer{

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/autoNext").withSockJS();
    }

    @Override
    public void configureMessageBroker(MessageBrokerRegistry registry) {
        registry.enableSimpleBroker("/topic");
        registry.setApplicationDestinationPrefixes("/app");
    }
}

This is controller class for the messenger application 

@Controller
public class ChatController {
@Autowired  
private ChatService chatService;

    @MessageMapping("/chat.register")
    @SendTo("/topic/public")
    public ChatMessage register(@Payload ChatMessage chatMessage, SimpMessageHeaderAccessor headerAccessor) {


        headerAccessor.getSessionAttributes().put("username", chatMessage.getSender());
        System.out.println(chatMessage);
        chatService.saveChat(chatMessage);
        return chatMessage;
    }

    @MessageMapping("/chat.send")
    @SendTo("/topic/public")
    public ChatMessage sendMessage(@Payload ChatMessage chatMessage) {
        System.out.println(chatMessage);
        chatService.saveChat(chatMessage);
        return chatMessage;

    }

}

This is chat entity where in MYSQL entity class:

    @Document(collection="chat_collection")
    public class ChatEntity {
    @Id
    private int id;
    @Field("content")
    private String content;
    @Field("sender")
    private String sender;


    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getSender() {
        return sender;
    }

    public void setSender(String sender) {
        this.sender = sender;
    }

This is Service class

@Service
public class ChatService {

@Autowired  
private ChatRepository chatRepository;

public void saveChat(ChatMessage chatMessage) {
    ChatEntity chatEntity=new ChatEntity();
    BeanUtils.copyProperties(chatMessage, chatEntity);
    chatRepository.insert(chatEntity);
}
}

This is Repository

@Repository
public interface ChatRepository extends MongoRepository <ChatEntity, Integer> {

}


error log:

Caused by: com.mongodb.MongoWriteException: E11000 duplicate key error collection: ChatBox.chat_collection index: _id_ dup key: { _id: 0 }
    at com.mongodb.client.internal.MongoCollectionImpl.executeSingleWriteRequest(MongoCollectionImpl.java:967) ~[mongodb-driver-3.8.2.jar:na]
    at com.mongodb.client.internal.MongoCollectionImpl.executeInsertOne(MongoCollectionImpl.java:494) ~[mongodb-driver-3.8.2.jar:na]
    at com.mongodb.client.internal.MongoCollectionImpl.insertOne(MongoCollectionImpl.java:478) ~[mongodb-driver-3.8.2.jar:na]
    at com.mongodb.client.internal.MongoCollectionImpl.insertOne(MongoCollectionImpl.java:472) ~[mongodb-driver-3.8.2.jar:na]
    at org.springframework.data.mongodb.core.MongoTemplate$6.doInCollection(MongoTemplate.java:1436) ~[spring-data-mongodb-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.data.mongodb.core.MongoTemplate.execute(MongoTemplate.java:538) ~[spring-data-mongodb-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    ... 52 common frames omitted

2020-02-19 16:36:36.030  INFO 21228 --- [MessageBroker-2] o.s.w.s.c.WebSocketMessageBrokerStats    : WebSocketSession[1 current WS(1)-HttpStream(0)-HttpPoll(0), 1 total, 0 closed abnormally (0 connect failure, 0 send limit, 0 transport error)], stompSubProtocol[processed CONNECT(1)-CONNECTED(1)-DISCONNECT(0)], stompBrokerRelay[null], inboundChannel[pool size = 8, active threads = 0, queued tasks = 0, completed tasks = 18], outboundChannel[pool size = 2, active threads = 0, queued tasks = 0, completed tasks = 2], sockJsScheduler[pool size = 4, active threads = 1, queued tasks = 2, completed tasks = 10]