java实现websocket的五种方式

1. 前言

WebSocket 是 HTML5 一种新的协议。它实现了浏览器与服务器全双工通信,能更好的节省服务器资源和带宽并达到实时通讯,它建立在 TCP 之上.

本文主要讲述在Java技术领域实现websocket服务的五种方式.

2. 第一种使用Java原生代码实现websocket

使用Java原生代码实现websocket服务的方法, 此方法需要引入一个第三方库java-websocket.jar. 截至目前2023/01/01最新版本为1.5.3.

项目源代码位于:

https://github.com/TooTallNate/Java-WebSocket

示例代码位于:

https://github.com/TooTallNate/Java-WebSocket/tree/master/src/main/example

2.1. 首先在项目中引入依赖

如果你的项目使用gradle作为管理工具, 可以添加以下gradle依赖

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implementation group: 'org.java-websocket', name: 'Java-WebSocket', version: '1.5.3'

如果你的项目使用maven进行管理, 可以添加以下maven依赖

mven依赖

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<dependency>
<groupId>org.java-websocket</groupId>
<artifactId>Java-WebSocket</artifactId>
<version>1.5.3</version>
</dependency>

2.2. 创建WebsocketServer类

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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;

import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

public class SocketServer extends WebSocketServer {

public SocketServer(int port) throws UnknownHostException {
super(new InetSocketAddress(port));
}

public SocketServer(InetSocketAddress address) {
super(address);
}

@Override
public void onOpen(WebSocket conn, ClientHandshake handshake) {
conn.send("Welcome to the server!"); // This method sends a message to the new client
broadcast("new connection: " + handshake
.getResourceDescriptor()); // This method sends a message to all clients connected
System.out.println(
conn.getRemoteSocketAddress().getAddress().getHostAddress() + " entered the room!");

}

@Override
public void onClose(WebSocket conn, int code, String reason, boolean remote) {
broadcast(conn + " has left the room!");
System.out.println(conn + " has left the room!");

}

@Override
public void onMessage(WebSocket conn, String message) {

broadcast(message);
System.out.println(conn + ": " + message);
}

@Override
public void onError(WebSocket conn, Exception ex) {
ex.printStackTrace();
if (conn != null) {
// some errors like port binding failed may not be assignable to a specific
// websocket
}

}

@Override
public void onStart() {
System.out.println("Server started!");
setConnectionLostTimeout(0);
setConnectionLostTimeout(100);

}

}

2.3. 启动SocketServer

我们以及创建好了SocketServer, 这个时候我们可以启动它了, 启动代码如下.

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public static void main(String[] args) throws InterruptedException, IOException {
int port = 8887; // 843 flash policy port

SocketServer s = new SocketServer(port);
s.start();
System.out.println("ChatServer started on port: " + s.getPort());

BufferedReader sysin = new BufferedReader(new InputStreamReader(System.in));
while (true) {
String in = sysin.readLine();
s.broadcast(in);
if (in.equals("exit")) {
s.stop(1000);
break;
}
}
}

写好main方法后, 我们可以启动它, 当控制台输出ChatServer started on port: 8887表示启动成功.

2.4. 测试web socket server

此时web socket server已经监听在了localhost:8887上. 我们可以使用websocket在线调试工具对其进行测试.

该工具主要是利用html5 的websocket去连接服务端的websocket,因此,
无论你是内网还是外网都可使用!

打开工具在输入框中输入 ws://localhost:8887点击连接, 既可以看到服务器端的反馈, 同时web socket server的控制台也会输出日志信息.

3. 使用Java原生+SpringBoot混合

在此种方式中, SocketServer依然使用原生的java代码编写, 但是SocketServer实例化过程由spring来管理.

此时我们需要引入spring-boot-starter-websocket, 上一节中的依赖包Java-WebSocket已经不需要了. 两种方式采用了不同的机制.

可以参考我的博文创建spring boot项目, 里面有详细讲解 - 如何手动创建一个springBoot项目

3.1. 引入依赖

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plugins {

id 'org.springframework.boot' version '2.7.7'
id 'io.spring.dependency-management' version '1.0.15.RELEASE'

}

dependencies {

implementation 'org.springframework.boot:spring-boot-starter-websocket'

}

此处我们需要在gradle配置文件的plugins闭包内添加两个plugins, 一个复制控制spring boot的版本, 一个负责管理依赖.

对于maven, 需要如下配置

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<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.7</version>
<relativePath/>
</parent>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
</dependencies>

3.2. 创建ServerEndpoint

创建ServerEndpoint代码如下:

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import org.springframework.stereotype.Component;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;

@ServerEndpoint("/myWs")
@Component
public class WsServerEndpoint {

/**
* 连接成功
*
* @param session
*/
@OnOpen
public void onOpen(Session session) {
System.out.println("连接成功");
}

/**
* 连接关闭
*
* @param session
*/
@OnClose
public void onClose(Session session) {
System.out.println("连接关闭");
}

/**
* 接收到消息
*
* @param text
*/
@OnMessage
public String onMsg(String text) throws IOException {
return "servet 发送:" + text;
}
}

说明
这里有几个注解需要注意一下,首先是他们的包都在 javax.websocket下。并不是 spring 提供的,而 jdk 自带的,下面是他们的具体作用。

  1. @ServerEndpoint
    通过这个 spring boot 就可以知道你暴露出去的 ws 应用的路径,有点类似我们经常用的@RequestMapping。比如你的启动端口是 8080,而这个注解的值是 ws,那我们就可以通过 ws://127.0.0.1:8080/ws 来连接你的应用

  2. @OnOpen
    当 websocket 建立连接成功后会触发这个注解修饰的方法,注意它有一个 Session 参数

  3. @OnClose
    当 websocket 建立的连接断开后会触发这个注解修饰的方法,注意它有一个 Session 参数

  4. @OnMessage
    当客户端发送消息到服务端时,会触发这个注解修改的方法,它有一个 String 入参表明客户端传入的值

  5. @OnError
    当 websocket 建立连接时出现异常会触发这个注解修饰的方法,注意它有一个 Session 参数

  6. 服务器主动发送消息
    当服务器端要主动给客户端发送, 需要获取到相应客户端与服务器端的session, 通过 session.getBasicRemote().sendText(), 将消息发送到前端.
    因此最好在onOpen方法中将session对象保存起来, 这样下次主动连接客户端时能找到相应的session对象.

3.3. 添加Spring配置

有了WsServerEndpoint后我们还要配置ServerEndpointExporter, 将Endpoint暴露出去让客户端来建立连接.

而配置ServerEndpointExporter的方式非常简单, 只需要创建一个ServerEndpointExporter bean即可, 它会去获取Spring上下文中所有的Endpoint实例, 完成endpoint的注册过程, 并监听在application.properties 的server.port 属性所指定的端口.

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import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
@EnableWebSocket
public class WebsocketConfig {

@Bean
public ServerEndpointExporter serverEndpoint() {
return new ServerEndpointExporter();
}

}

3.4. 启动应用程序并测试

我们只需要向一般的Spring boot应用一样启动它即可.

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@SpringBootApplication
public class App {

public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}

测试, 我们依然使用websocket在线调试工具来测试, 详情可参考上一节中的介绍

与前一种实现方式稍微不同的地方是, 我们可以url中指定endpoint了 ws://127.0.0.1:8080/myWs

4. 使用SpringBoot实现websocket

4.1. 引入依赖

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implementation 'org.springframework.boot:spring-boot-starter-websocket'

4.2. 实现类

HttpAuthHandler.java

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import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
import java.time.LocalDateTime;

@Component
public class HttpAuthHandler extends TextWebSocketHandler {

/**
* socket 建立成功事件
*
* @param session
* @throws Exception
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
Object sessionId = session.getAttributes().get("session_id");
if (sessionId != null) {
// 用户连接成功,放入在线用户缓存
WsSessionManager.add(sessionId.toString(), session);
} else {
throw new RuntimeException("用户登录已经失效!");
}
}

/**
* 接收消息事件
*
* @param session
* @param message
* @throws Exception
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
// 获得客户端传来的消息
String payload = message.getPayload();
Object sessionId = session.getAttributes().get("session_id");
System.out.println("server 接收到 " + sessionId + " 发送的 " + payload);
session.sendMessage(new TextMessage("server 发送给 " + sessionId + " 消息 " + payload + " " + LocalDateTime.now().toString()));
}

/**
* socket 断开连接时
*
* @param session
* @param status
* @throws Exception
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
Object sessionId = session.getAttributes().get("session_id");
if (sessionId != null) {
// 用户退出,移除缓存
WsSessionManager.remove(sessionId.toString());
}
}


}

WsSessionManager.java

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import org.springframework.web.socket.WebSocketSession;

import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;

public class WsSessionManager {
/**
* 保存连接 session 的地方
*/
private static ConcurrentHashMap<String, WebSocketSession> SESSION_POOL = new ConcurrentHashMap<>();

/**
* 添加 session
*
* @param key
*/
public static void add(String key, WebSocketSession session) {
// 添加 session
SESSION_POOL.put(key, session);
}

/**
* 删除 session,会返回删除的 session
*
* @param key
* @return
*/
public static WebSocketSession remove(String key) {
// 删除 session
return SESSION_POOL.remove(key);
}

/**
* 删除并同步关闭连接
*
* @param key
*/
public static void removeAndClose(String key) {
WebSocketSession session = remove(key);
if (session != null) {
try {
// 关闭连接
session.close();
} catch (IOException e) {
// todo: 关闭出现异常处理
e.printStackTrace();
}
}
}

/**
* 获得 session
*
* @param key
* @return
*/
public static WebSocketSession get(String key) {
// 获得 session
return SESSION_POOL.get(key);
}
}


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import java.util.Map;

import org.apache.logging.log4j.util.Strings;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.HandshakeInterceptor;

@Component
public class MyInterceptor implements HandshakeInterceptor {

/**
* 握手前
*/
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
System.out.println("握手开始");
String hostName = request.getRemoteAddress().getHostName();
String sessionId = hostName+String.valueOf((int)(Math.random()*1000));
if (Strings.isNotBlank(sessionId)) {
// 放入属性域
attributes.put("session_id", sessionId);
System.out.println("用户 session_id " + sessionId + " 握手成功!");
return true;
}
System.out.println("用户登录已失效");
return false;
}

/**
* 握手后
*/
@Override
public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {
System.out.println("握手完成");
}

}

4.3. Spring 配置

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import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

import com.philoenglish.ws.HttpAuthHandler;
import com.philoenglish.ws.MyInterceptor;

@Configuration
@EnableWebSocket
public class WebsocketConfig implements WebSocketConfigurer {

@Autowired
private HttpAuthHandler httpAuthHandler;
@Autowired
private MyInterceptor myInterceptor;

@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry
.addHandler(httpAuthHandler, "myWS")
.addInterceptors(myInterceptor)
.setAllowedOrigins("*");
}

}

4.4. 启动与测试

启动代码如下:

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import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class App {

public static void main(String[] args) {
SpringApplication.run(App.class, args);
}

@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
return args -> {

System.out.println("application started");

};
}
}

执行main方法启动应用程序

测试依然使用websocket在线调试工具

5. 使用TIO+SpringBoot实现websocket

以下是关于t-io的一些信息, 如果需要更详细的了解tio可以访问以下这些站点

sitlink
t-io sitehttps://www.t-io.org
t-io on giteehttps://gitee.com/tywo45/t-io
t-io on githubhttps://github.com/tywo45/t-io

5.1. 添加相应依赖

gradle:

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implementation 'org.t-io:tio-websocket-spring-boot-starter:3.6.0.v20200315-RELEASE'

maven:

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 <dependency>
<groupId>org.t-io</groupId>
<artifactId>tio-websocket-spring-boot-starter</artifactId>
<version>3.6.0.v20200315-RELEASE</version>
</dependency>

5.2. 编写消息处理类

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import org.springframework.stereotype.Component;
import org.tio.core.ChannelContext;
import org.tio.http.common.HttpRequest;
import org.tio.http.common.HttpResponse;
import org.tio.websocket.common.WsRequest;
import org.tio.websocket.server.handler.IWsMsgHandler;


@Component
public class MyWebSocketMsgHandler implements IWsMsgHandler {

@Override
public HttpResponse handshake(HttpRequest httpRequest, HttpResponse httpResponse, ChannelContext channelContext)
throws Exception {
return httpResponse;
}

@Override

public void onAfterHandshaked(HttpRequest httpRequest, HttpResponse httpResponse, ChannelContext channelContext)
throws Exception {
System.out.println("握手成功");
}

@Override
public Object onBytes(WsRequest wsRequest, byte[] bytes, ChannelContext channelContext) throws Exception {
System.out.println("接收到bytes消息");
return null;
}

@Override
public Object onClose(WsRequest wsRequest, byte[] bytes, ChannelContext channelContext) throws Exception {
return null;
}

@Override
public Object onText(WsRequest wsRequest, String s, ChannelContext channelContext) throws Exception {
System.out.println("接收到文本消息:" + s);
return null;
}
}

5.3. 修改配置文件

application.properties

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tio.websocket.server.port=9876
tio.websocket.server.heartbeat-timeout=60000

5.4. 启动tio Websocket Server

启动tio Websocket Server 的方式如下, 执行main方法.

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@SpringBootApplication
@EnableTioWebSocketServer
public class App {

public static void main(String[] args) {
SpringApplication.run(App.class, args);
}

@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
return args -> {
System.out.println("application started");
};
}
}

6. STOMP实现websocket

6.1. 添加相应依赖

gradle:

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implementation 'org.springframework.boot:spring-boot-starter-websocket'

maven:

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

6.2. 实现配置WebSocketMessageBrokerConfigurer接口

WebSocketConfig.java

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import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
// 配置客户端尝试连接地址
registry.addEndpoint("/ws").setAllowedOrigins("*");
}

@Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
// 设置广播节点
registry.enableSimpleBroker("/topic", "/queue");
// 客户端向服务端发送消息需有/app 前缀
registry.setApplicationDestinationPrefixes("/app");
// 指定用户发送(一对一)的前缀 /user/
registry.setUserDestinationPrefix("/user/");
}
}

6.3. 实现消息请求处理的Controller

WSController.java

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import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.messaging.simp.annotation.SendToUser;
import org.springframework.stereotype.Controller;

@Controller
public class WSController {

@Autowired
private SimpMessagingTemplate simpMessagingTemplate;

@MessageMapping("/greeting")
@SendToUser("/queue/serverReply")
public String greating(@Payload String data) {
System.out.println("received greeting: " + data);
String msg = "server replys: " + data;
return msg;
}

@MessageMapping("/shout")
public void userShout(Shout shout) {
//String name = principal.getName();
String message = shout.getMessage();
System.out.println("收到的消息是:" + message);
simpMessagingTemplate.convertAndSend("/queue/notifications", shout);

}

}

domain object

Shout.java

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public class Shout {

private String message;

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}
}

6.4. 启动

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import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class App {

public static void main(String[] args) {
SpringApplication.run(App.class, args);
}

@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
return args -> {

System.out.println("application started");

};
}
}

6.5. 实现消息客户端

index.html

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<!DOCTYPE html>
<html lang="en">

<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<title>Document</title>
<style>
.newmessage {
color: green;
}
.errormessage {
color: red;
}
</style>
</head>

<body>
<div class="row">
<div class="col-lg-6">
<div class="input-group">
<input type="text" id='urlInput' class="form-control" placeholder='输入websocket端点'>
<span class="input-group-btn">
<button class="btn btn-default" type="button" onclick="reconnect();">重新连接</button>
</span>
</div>
</div>
<div class="col-lg-8" id="output" style="border:1px solid #ccc;height:365px;overflow: auto;margin-left:15px">
</div>
<div class="col-lg-6">
<div class="input-group">
<input type="text" id='messageInput' class="form-control" placeholder='待发信息'>
<span class="input-group-btn">
<button class="btn btn-default" type="button" onclick="doSend();">发送</button>
</span>
<span class="input-group-btn">
<button class="btn btn-default" type="button" onclick="broadcast();">广播</button>
</span>
</div>
</div>
</div>

</body>
<script src="https://cdn.bootcss.com/stomp.js/2.3.3/stomp.min.js"></script>
<script src="http://cdn.static.runoob.com/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://cdn.static.runoob.com/libs/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script type="text/javascript">

var defaultUrl = "ws://localhost:81/ws"
document.getElementById("urlInput").value = defaultUrl;

var stomp;

var appendMessage = function (msg) {
var div = "<div class='newmessage'>" + msg + "</div>";
$("#output").append(div);
}

var reportError = function (msg) {
var div = "<div class='errormessage'>" + msg + "</div>";
$("#output").append(div);
}

function connects(url) {
var promise = new Promise(function (resolve, reject) {
var client = Stomp.client(url);

var headers = {
username: 'admin',
password: 'admin',
// additional header
'client-id': 'stomp-client-id'
};

appendMessage('connecting to ' + url)
client.connect(headers, function (frame) {
resolve(client);
}, function (error) {
reject(error)
});
});
return promise;
}

var connect_callback = function (client) {
stomp = client
appendMessage('subscribing on ' + '/queue/subscribe')

client.subscribe('/user/queue/serverReply', function (message) {
console.log('subscribe topic callback:' + message.body);
appendMessage('subscribe topic callback:' + message.body)
});

appendMessage('subscribing on ' + '/user/queue/notifications')

client.subscribe("/queue/notifications", function (message) {
var content = message.body;
var obj = JSON.parse(content);
console.log("收到广播消息:" + message.body);
appendMessage("收到广播消息:" + message.body);
});

var payload = JSON.stringify({ 'message': 'greeting to stomp broker!' });
client.send("/app/greeting", {}, payload);

};

var error_callback = function (error) {
reportError("连接失败!");
};

var doSend = function () {
var msg = document.getElementById("messageInput").value
var payload = JSON.stringify({ 'message': msg });
stomp.send("/app/greeting", {}, payload);
}

var broadcast = function () {
var msg = document.getElementById("messageInput").value
var payload = JSON.stringify({ 'message': msg });
stomp.send("/app/shout", {}, payload);
}

function reconnect() {
if (stomp) {
stomp.disconnect(function () {
console.log("See you next time!");
})
}
connects(document.getElementById("urlInput").value).then(connect_callback).catch(error_callback)

}
reconnect();

</script>

</html>

7. 相关文章

本技术博客原创文章位于鹏叔的技术博客 - java实现websocket的五种方式, 要获取最近更新请访问原文.

更多技术博客请访问: 鹏叔的技术博客

更新: 2023/04/14

上面所讲的都是关于Java程序作为服务端与前端通信. 在Websocket完整体系中还缺少了一块, 那就是服务端向客户端推送消息, 这时候则需要java作为客户端, 这里我写了一个java程序作为webSocket客户端的例子, 而不是将服务器代码耦合在WSController中, 希望我的这篇文章对您有所帮助使用stomp的java客户端向前端推送数据

8. 参考文档

websocket - spring boot 集成 websocket 的四种方式

websocket在线调试工具

JAVA实现WebSocket服务器

让网络编程更轻松和有趣 t-io

tio-websocket-spring-boot-starter 的简单使用

STOMP原理与应用开发详解

Spring消息之STOMP

WebSocket详解:技术原理、代码演示和应用案例

WebSocket 是什么原理?为什么可以实现持久连接

java实现websocket的五种方式

https://pengtech.net/java/spring_websocket.html

作者

鹏叔

发布于

2023-01-01

更新于

2024-07-10

许可协议

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