实现websocket的两种方式

简单说明

1.两种方式,一种使用tomcat的websocket实现,一种使用spring的websocket

2.tomcat的方式需要tomcat 7.x,JEE7的支持。

3.spring与websocket整合需要spring 4.x,并且使用了socketjs,对不支持websocket的浏览器可以模拟websocket使用


方式一:tomcat

使用这种方式无需别的任何配置,只需服务端一个处理类,


服务器端代码

package com.Socket;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import net.sf.json.JSONObject;

@ServerEndpoint("/websocket/{username}")
public class WebSocket {

	private static int onlineCount = 0;
	private static Map<String, WebSocket> clients = new ConcurrentHashMap<String, WebSocket>();
	private Session session;
	private String username;
	
	@OnOpen
	public void onOpen(@PathParam("username") String username, Session session) throws IOException {

		this.username = username;
		this.session = session;
		
		addOnlineCount();
		clients.put(username, this);
		System.out.println("已连接");
	}

	@OnClose
	public void onClose() throws IOException {
		clients.remove(username);
		subOnlineCount();
	}

	@OnMessage
	public void onMessage(String message) throws IOException {

		JSONObject jsonTo = JSONObject.fromObject(message);
		
		if (!jsonTo.get("To").equals("All")){
			sendMessageTo("给一个人", jsonTo.get("To").toString());
		}else{
			sendMessageAll("给所有人");
		}
	}

	@OnError
	public void onError(Session session, Throwable error) {
		error.printStackTrace();
	}

	public void sendMessageTo(String message, String To) throws IOException {
		// session.getBasicRemote().sendText(message);
		//session.getAsyncRemote().sendText(message);
		for (WebSocket item : clients.values()) {
			if (item.username.equals(To) )
				item.session.getAsyncRemote().sendText(message);
		}
	}
	
	public void sendMessageAll(String message) throws IOException {
		for (WebSocket item : clients.values()) {
			item.session.getAsyncRemote().sendText(message);
		}
	}
	
	

	public static synchronized int getOnlineCount() {
		return onlineCount;
	}

	public static synchronized void addOnlineCount() {
		WebSocket.onlineCount++;
	}

	public static synchronized void subOnlineCount() {
		WebSocket.onlineCount--;
	}

	public static synchronized Map<String, WebSocket> getClients() {
		return clients;
	}
}


客户端js

var websocket = null;
var username = localStorage.getItem("name");

//判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
	websocket = new WebSocket("ws://" + document.location.host + "/WebChat/websocket/" + username + "/"+ _img);
} else {
	alert('当前浏览器 Not support websocket')
}

//连接发生错误的回调方法
websocket.onerror = function() {
	setMessageInnerHTML("WebSocket连接发生错误");
};

//连接成功建立的回调方法
websocket.onopen = function() {
	setMessageInnerHTML("WebSocket连接成功");
}

//接收到消息的回调方法
websocket.onmessage = function(event) {
	setMessageInnerHTML(event.data);
}

//连接关闭的回调方法
websocket.onclose = function() {
	setMessageInnerHTML("WebSocket连接关闭");
}

//监听窗口关闭事件,当窗口关闭时,主动去关闭websocket连接,防止连接还没断开就关闭窗口,server端会抛异常。
window.onbeforeunload = function() {
	closeWebSocket();
}

//关闭WebSocket连接
function closeWebSocket() {
	websocket.close();
}


发送消息只需要使用websocket.send("发送消息"),就可以触发服务端的onMessage()方法,当连接时,触发服务器端onOpen()方法,此时也可以调用发送消息的方法去发送消息。关闭websocket时,触发服务器端onclose()方法,此时也可以发送消息,但是不能发送给自己,因为自己的已经关闭了连接,但是可以发送给其他人。


方法二:spring整合

此方式基于spring mvc框架,相关配置可以看我的相关博客文章


WebSocketConfig.java

这个类是配置类,所以需要在spring mvc配置文件中加入对这个类的扫描,第一个addHandler是对正常连接的配置,第二个是如果浏览器不支持websocket,使用socketjs模拟websocket的连接。

package com.websocket;

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.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
import org.springframework.web.socket.handler.TextWebSocketHandler;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(chatMessageHandler(),"/webSocketServer").addInterceptors(new ChatHandshakeInterceptor());
        registry.addHandler(chatMessageHandler(), "/sockjs/webSocketServer").addInterceptors(new ChatHandshakeInterceptor()).withSockJS();
    }
 
    @Bean
    public TextWebSocketHandler chatMessageHandler(){
        return new ChatMessageHandler();
    }

}



ChatHandshakeInterceptor.java

这个类的作用就是在连接成功前和成功后增加一些额外的功能,Constants.java类是一个工具类,两个常量。

package com.websocket;

import java.util.Map;
import org.apache.shiro.SecurityUtils;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;

public class ChatHandshakeInterceptor extends HttpSessionHandshakeInterceptor {

	@Override
	public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
			Map<String, Object> attributes) throws Exception {
		System.out.println("Before Handshake");
		/*
		 * if (request instanceof ServletServerHttpRequest) {
		 * ServletServerHttpRequest servletRequest = (ServletServerHttpRequest)
		 * request; HttpSession session =
		 * servletRequest.getServletRequest().getSession(false); if (session !=
		 * null) { //使用userName区分WebSocketHandler,以便定向发送消息 String userName =
		 * (String) session.getAttribute(Constants.SESSION_USERNAME); if
		 * (userName==null) { userName="default-system"; }
		 * attributes.put(Constants.WEBSOCKET_USERNAME,userName);
		 * 
		 * } }
		 */

		//使用userName区分WebSocketHandler,以便定向发送消息(使用shiro获取session,或是使用上面的方式)
		String userName = (String) SecurityUtils.getSubject().getSession().getAttribute(Constants.SESSION_USERNAME);
		if (userName == null) {
			userName = "default-system";
		}
		attributes.put(Constants.WEBSOCKET_USERNAME, userName);

		return super.beforeHandshake(request, response, wsHandler, attributes);
	}

	@Override
	public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
			Exception ex) {
		System.out.println("After Handshake");
		super.afterHandshake(request, response, wsHandler, ex);
	}

}


ChatMessageHandler.java

这个类是对消息的一些处理,比如是发给一个人,还是发给所有人,并且前端连接时触发的一些动作

package com.websocket;

import java.io.IOException;
import java.util.ArrayList;
import org.apache.log4j.Logger;
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;

public class ChatMessageHandler extends TextWebSocketHandler {

	private static final ArrayList<WebSocketSession> users;// 这个会出现性能问题,最好用Map来存储,key用userid
	private static Logger logger = Logger.getLogger(ChatMessageHandler.class);

	static {
		users = new ArrayList<WebSocketSession>();
	}

	/**
	 * 连接成功时候,会触发UI上onopen方法
	 */
	@Override
	public void afterConnectionEstablished(WebSocketSession session) throws Exception {
		System.out.println("connect to the websocket success......");
		users.add(session);
		// 这块会实现自己业务,比如,当用户登录后,会把离线消息推送给用户
		// TextMessage returnMessage = new TextMessage("你将收到的离线");
		// session.sendMessage(returnMessage);
	}

	/**
	 * 在UI在用js调用websocket.send()时候,会调用该方法
	 */
	@Override
	protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
		sendMessageToUsers(message);
		//super.handleTextMessage(session, message);
	}

	/**
	 * 给某个用户发送消息
	 *
	 * @param userName
	 * @param message
	 */
	public void sendMessageToUser(String userName, TextMessage message) {
		for (WebSocketSession user : users) {
			if (user.getAttributes().get(Constants.WEBSOCKET_USERNAME).equals(userName)) {
				try {
					if (user.isOpen()) {
						user.sendMessage(message);
					}
				} catch (IOException e) {
					e.printStackTrace();
				}
				break;
			}
		}
	}

	/**
	 * 给所有在线用户发送消息
	 *
	 * @param message
	 */
	public void sendMessageToUsers(TextMessage message) {
		for (WebSocketSession user : users) {
			try {
				if (user.isOpen()) {
					user.sendMessage(message);
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	@Override
	public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
		if (session.isOpen()) {
			session.close();
		}
		logger.debug("websocket connection closed......");
		users.remove(session);
	}

	@Override
	public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
		logger.debug("websocket connection closed......");
		users.remove(session);
	}

	@Override
	public boolean supportsPartialMessages() {
		return false;
	}

}



spring-mvc.xml

正常的配置文件,同时需要增加对WebSocketConfig.java类的扫描,并且增加

xmlns:websocket="http://www.springframework.org/schema/websocket"
              http://www.springframework.org/schema/websocket 
			  http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd



客户端

<script type="text/javascript"
		src="http://localhost:8080/Bank/js/sockjs-0.3.min.js"></script>
	<script>
		var websocket;
	
		if ('WebSocket' in window) {
			websocket = new WebSocket("ws://" + document.location.host + "/Bank/webSocketServer");
		} else if ('MozWebSocket' in window) {
			websocket = new MozWebSocket("ws://" + document.location.host + "/Bank/webSocketServer");
		} else {
			websocket = new SockJS("http://" + document.location.host + "/Bank/sockjs/webSocketServer");
		}
	
		websocket.onopen = function(evnt) {};
		websocket.onmessage = function(evnt) {
			$("#test").html("(<font color='red'>" + evnt.data + "</font>)")
		};
	
		websocket.onerror = function(evnt) {};
		websocket.onclose = function(evnt) {}
	
		$('#btn').on('click', function() {
			if (websocket.readyState == websocket.OPEN) {
				var msg = $('#id').val();
				//调用后台handleTextMessage方法
				websocket.send(msg);
			} else {
				alert("连接失败!");
			}
		});
	</script>

注意导入socketjs时要使用地址全称,并且连接使用的是http而不是websocket的ws






你可能感兴趣的:(spring,tomcat,websocket)