Java 颤振跺脚客户端无法与spring跺脚客户端连接

一、 我是新来的。我正在尝试连接到使用stomp的SpringWebSocket，但连接失败。我使用的是stomp_dart_客户端0.3.3。弹簧切断器工作正常。我可以在浏览器上看到消息

这是我的spring实现：

StompClient stompClient = StompClient(
        config: StompConfig(
          url: 'ws://10.0.2.2:7000',
          onConnect:(ss, dd)=> ss.subscribe (
            destination: '/topic/greetings/gs-guide-websocket',
            callback: (StompFrame frame) {
              print(frame.body);
            },
          ),
          onWebSocketError: (dynamic error) => print(error.toString()),
          onStompError: (d) => print("stomp error"),
          onDisconnect: (d)=> print("disconnect"),
        ));

   stompClient.activate();

   stompClient.subscribe (
        destination: '/topic/greetings',
        callback: (StompFrame frame) {
          print(frame.body);
          List<dynamic> result = json.decode(frame.body);
          return result;
        },
    );

Spring配置类：

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

@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
    registry.addEndpoint("/gs-guide-websocket").withSockJS();
}

弹簧控制器：

@MessageMapping("/hello")
@SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
    Thread.sleep(1000); // simulated delay
    return new Greeting("Hello, " + HtmlUtils.htmlEscape(message.getName()) + "!");
}

颤振实施：

StompClient stompClient = StompClient(
        config: StompConfig(
          url: 'ws://10.0.2.2:7000',
          onConnect:(ss, dd)=> ss.subscribe (
            destination: '/topic/greetings/gs-guide-websocket',
            callback: (StompFrame frame) {
              print(frame.body);
            },
          ),
          onWebSocketError: (dynamic error) => print(error.toString()),
          onStompError: (d) => print("stomp error"),
          onDisconnect: (d)=> print("disconnect"),
        ));

   stompClient.activate();

   stompClient.subscribe (
        destination: '/topic/greetings',
        callback: (StompFrame frame) {
          print(frame.body);
          List<dynamic> result = json.decode(frame.body);
          return result;
        },
    );

这就是错误：

E/flutter (30825): [ERROR:flutter/shell/common/shell.cc(213)] Dart Error: Unhandled exception:
E/flutter (30825): NoSuchMethodError: The method 'subscribe' was called on null.
E/flutter (30825): Receiver: null
E/flutter (30825): Tried calling: subscribe(callback: Closure: (StompFrame) => List<dynamic>, destination: "/topic/greetings", headers: null)
E/flutter (30825): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
E/flutter (30825): #1      StompClient.subscribe (package:stomp_dart_client/stomp.dart:74:21)
E/flutter (30825): #2      _MyHomePageState._receivedMessage (package:tutorial_projecect/main.dart:154:16)
E/flutter (30825): #3      _MyHomePageState.build (package:tutorial_projecect/main.dart:90:41)
E/flutter (30825): #4      StatefulElement.build (package:flutter/src/widgets/framework.dart:4619:28)
E/flutter (30825): #5      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4502:15)
E/flutter (30825): #6      StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
E/flutter (30825): #7      Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #8      StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
E/flutter (30825): #9      Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #10     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #11     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #12     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
E/flutter (30825): #13     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #14     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
E/flutter (30825): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #16     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #17     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #18     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #19     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #20     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
E/flutter (30825): #21     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
E/flutter (30825): #22     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #23     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
E/flutter (30825): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #25     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #26     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #27     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #28     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #29     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
E/flutter (30825): #30     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
E/flutter (30825): #31     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #32     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
E/flutter (30825): #33     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #34     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
E/flutter (30825): #35     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #36     StatelessElement.update (package:flutter/src/widgets/framework.dart:4583:5)
E/flutter (30825): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #38     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4527:16)
E/flutter (30825): #39     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4675:11)
E/flutter (30825): #40     Element.rebuild (package:flutter/src/widgets/framework.dart:4218:5)
E/flutter (30825): #41     StatefulElement.update (package:flutter/src/widgets/framework.dart:4707:5)
E/flutter (30825): #42     Element.updateChild (package:flutter/src/widgets/framework.dart:3201:15)
E/flutter (30825): #43     SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5837:14)
E/flutter (30825): #44     Element.updateCh

---

经过一些调查和重试，我发现了这个问题。 registerStompEndpoints不应返回SockJs

我还使用了另一个stomp lib:stomp:^0.8.0

@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
    registry.addEndpoint("/gs-guide-websocket");
}

首先。 您的原始帖子应该在onConnect回调中使用stompClient.subscribe。如果在连接之前订阅，则客户端对象为空

其次 因为你换了一个库。你应该展示你的新代码。我两个都试过了。并跺脚：^0.8.0给出

java.lang.IllegalArgumentException: Invalid character found in method name [STOMP0x0aaccept-version:1.20x0a0x0a...]. HTTP method names must be tokens

---

仍然很难让它工作…

把这篇文章放回到原来提到stomp_dart_客户端的帖子，我很难在internet和堆栈溢出上找到这方面的工作示例，所以下面是我的解决方案，可能会有所帮助

我将RabbitMQ与webstomp插件一起使用，将JSON数据包发布到一个名为ping的队列中。stomp_dart_客户端的示例和文档不清楚如何连接到安全会话，我通过在头中添加身份验证解决了这一问题：

import 'dart:convert';

import 'package:stomp_dart_client/stomp.dart';
import 'package:stomp_dart_client/stomp_config.dart';
import 'package:stomp_dart_client/stomp_frame.dart';

dynamic onConnect(StompClient client, StompFrame frame) {
  client.subscribe(
      destination: 'ping',
      callback: (StompFrame frame) {
        var jsonData = json.decode(frame.body);
        print(jsonData);
      });
}

final stompClient = StompClient(
    config: StompConfig(
        url: 'ws://x.x.x.x:15674/ws',
        onConnect: onConnect,
        onWebSocketError: (dynamic error) => print(error.toString()),
        stompConnectHeaders: {
      'login': 'someuserlogin',
      'passcode': 'somepassword'
    },
));

void main() {
  stompClient.activate();
}

---

嗨，塞德！我也是个新手，我正试着做你所做的。你有没有遵循任何你可以发给我的教程？非常感谢。