websocket使用小例子

hulu321發表於2015-01-29
Web
1、後臺程式碼Websocket.java
package com.sinosoft.tyoa.websocket;

import java.io.IOException;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;

import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint("/websocket")
public class Websocket {

	private static Map<String,Session> sessionMap = new Hashtable<String,Session>();


	@OnMessage
	public void onMessage(String message, Session currentSession) {


		/*// Send the  message to the client
		Set<Map.Entry<String,Session>> set = sessionMap.entrySet();
        for (Map.Entry<String,Session> session: set) {
        	if(session.getValue().isOpen() == true) {
        		try {
        			System.out.println(session.getValue());
					session.getValue().getBasicRemote().sendText(message);
				} catch (IOException e) {
					sessionMap.remove(session.getValue());
					//e.printStackTrace();
				}
        	}
        	else {
        		System.out.println("close:"+session.getValue());
        		sessionMap.remove(session.getValue());
        	}
        }*/

		 //伺服器往各個客戶端傳送訊息
        Iterator<String> iterator = sessionMap.keySet().iterator();
        while(iterator.hasNext()) {
        	String key = (String) iterator.next();
        	Session session = sessionMap.get(key);
        	if(session.isOpen() == true) {
        		try {
					session.getBasicRemote().sendText(message);
				} catch (IOException e) {
					iterator.remove();
	        		sessionMap.remove(key);
					//e.printStackTrace();
				}
        	}
        	else {
        		iterator.remove();
        		sessionMap.remove(key);
        	}
        }
	}

	@OnOpen
	public void onOpen(Session currentSession) {
		if(sessionMap.containsValue(currentSession) == false){
			sessionMap.put(currentSession.getId(), currentSession);
        }
		//System.out.println("Client connected");
	}

	@OnClose
	public void onClose(Session currentSession)  throws IOException{
		sessionMap.remove(currentSession.getId());
		//System.out.println("Client closed");
	}

	@OnError
	public void onClose(Session currentSession,java.lang.Throwable throwable)  throws IOException{
		sessionMap.remove(currentSession.getId());
		//System.out.println("Client closed");
	}
}


2、pom.xml檔案配置
    <!-- websocket -->
		<dependency>
			<groupId>javax.websocket</groupId>
			<artifactId>javax.websocket-api</artifactId>
			<version>1.0</version>
			<scope>provided</scope>
		</dependency>
		<!-- websocket end -->

3、前臺頁面
<%@ page language="java" pageEncoding="UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = "ws" + "://"+ request.getServerName() + ":" + request.getServerPort() + path + "/";
%>
 <script type="text/javascript">
	var wsURI = "<%=basePath%>websocket";
	var websocket = null;

	function connectWebSocket(wsURI) {
		if(websocket == null) {
			websocket = new WebSocket(wsURI);
			websocket.onopen = function(openEvent) {
				$("#showMsg").append("連線成功...<br/>");
			};
			websocket.onclose = function(closeEvent) {
				websocket == null;
				$("#showMsg").append("關閉連線成功...<br/>");
			};
			websocket.onmessage = function(messageEvent) {
				$("#showMsg").append("<span style='display:block'>" + messageEvent.data + "</span>");
			};
			websocket.onerror = function(errorEvent) {
				//alert(errorEvent.data);
			};
		}
	}

	function sendMessageToClient(message) {
		websocket.send(message);
	}


	$("#sendButton").click(function() {
		sendMessageToClient($("#msg").val());
		$("#msg").val("");
	});


	$(function(){
		if(!("WebSocket" in window)){
			alert("瀏覽器不支援！");
		}
		else {
			connectWebSocket(wsURI);
		}
	});
 </script>
 <body>
    <div id="showMsg" style="border: 1px solid; width: 500px; height: 400px; overflow: auto;"></div>
    <div>
        <input type="text" id="msg" /> 
        <input type="button" id="sendButton" value="傳送" />
    </div>
</body>




3、[color=red]出現錯誤可能原因：專案有攔截器，把/webscoket新增到可訪問路徑；jar包配置問題，tomcat7有支援jar包，所有pom.xml裡面要依賴jar包要設定編譯需要而釋出不需要。[/color]

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