我是Flutter的新朋友。我正在尝试连接到使用stomp的spring websocket,但连接失败。我正在使用stomp_dart_client 0.3.3。春季服务器工作正常。我可以在浏览器中看到消息。
这是我的春季实施:
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();
}
Spring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()) + "!");
}
Flutter的实现:
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;
},
);
这是错误:
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
答案 0 :(得分:1)
您的原始帖子应在onConnect回调中使用stompClient.subscribe
。如果您在连接之前订阅,则客户端对象为空。
由于您更改了库。您应该显示新代码。我都尝试过lib。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
仍在努力使其发挥作用...
答案 1 :(得分:0)
经过一些调查和重试后,我发现了问题。 registerStompEndpoints不应返回SockJ。
我使用了另一个stomp lib:stomp:^ 0.8.0
@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/gs-guide-websocket");
}
答案 2 :(得分:0)
将其放回到提到stomp_dart_client的原始帖子中,我很难在Internet和Stack Overflow上找到可行的示例,因此这是我的解决方案,可能会有所帮助。
我正在将RabbitMQ与Web STOMP插件一起使用:https://www.rabbitmq.com/web-stomp.html,将JSON数据包发布到称为“ ping”的队列中。 stomp_dart_client的示例和文档尚不清楚如何连接到安全会话,我已通过在标头中添加身份验证解决了该安全会话:
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();
}