import?java.io.IOException;
import?java.util.concurrent.CopyOnWriteArraySet;

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?注解是一個類層次的注解，它的功能主要是將目前的類定義成一個websocket服務器端
?*?注解的值將被用于監聽用戶連接的終端訪問URL地址客戶端可以通過這個URL來連接到WebSocket服務器端
?*/
@ServerEndpoint（“/socketdemo“）
public?class?WebSocketDemo{
????//靜態變量，用來記錄當前在線連接數。應該把它設計成線程安全的。
????private?static?int?onlineCount?=?0;

????//concurrent包的線程安全Set，用來存放每個客戶端對應的MyWebSocket對象。若要實現服務端與單一客戶端通信的話，可以使用Map來存放，其中Key可以為用戶標識
????private?static?CopyOnWriteArraySet?webSocketSet?=?new?CopyOnWriteArraySet（）;

????//與某個客戶端的連接會話，需要通過它來給客戶端發送數據
????private?Session?session;

????/**
?????*?連接建立成功調用的方法
?????*?@param?session??可選的參數。session為與某個客戶端的連接會話，需要通過它來給客戶端發送數據
?????*/
????@OnOpen
????public?void?onOpen（Session?session）{
????????this.session?=?session;
????????webSocketSet.add（this）;?????//加入set中
????????addOnlineCount（）;???????????//在線數加1
????????System.out.println（“有新連接加入！當前在線人數為“?+?getOnlineCount（））;
????}

????/**
?????*?連接關閉調用的方法
?????*/
????@OnClose
????public?void?onClose（）{
????????webSocketSet.remove（this）;??//從set中刪除
????????subOnlineCount（）;???????????//在線數減1
????????System.out.println（“有一連接關閉！當前在線人數為“?+?getOnlineCount（））;
????}

????/**
?????*?收到客戶端消息后調用的方法
?????*?@param?message?客戶端發送過來的消息
?????*?@param?session?可選的參數
?????*/
????@OnMessage
????public?void?onMessage（String?message?Session?session）?{
????????System.out.println（“來自客戶端的消息:“?+?message）;
????????//群發消息
????????for（WebSocketDemo?item:?webSocketSet）{
????????????try?{
????????????????item.sendMessage（message）;
????????????}?catch?（IOException?e）?{
????????????????e.printStackTrace（）;
????????????????continue;
????????????}
????????}
????}

????/**
?????*?發生錯誤時調用
?????*?@param?session
?????*?@param?error
?????*/
????@onerror
????public?void?onerror（Session?session?Throwable?error）{
????????System.out.println（“發生錯誤“）;
????????error.printStackTrace（）;
????}

????/**
?????*?這個方法與上面幾個方法不一樣。沒有用注解，是根據自己需要添加的方法。
?????*?@param?message
?????*?@throws?IOException
?????*/
????public?void?sendMessage（String?message）?throws?IOException{
????????this.session.getBasicRemote（）.sendText（message）;
????????//this.session.getAsyncRemote（）.sendText（message）;
????}

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

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

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

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\
?????文件?????????996??2017-05-16?09:08??WebSocketDemo\.classpath
?????文件????????1046??2017-05-16?09:08??WebSocketDemo\.project
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\.settings\
?????文件?????????517??2017-05-16?09:08??WebSocketDemo\.settings\.jsdtscope
?????文件?????????364??2017-05-16?09:08??WebSocketDemo\.settings\org.eclipse.jdt.core.prefs
?????文件?????????471??2017-05-16?09:08??WebSocketDemo\.settings\org.eclipse.wst.common.component
?????文件?????????305??2017-05-16?09:08??WebSocketDemo\.settings\org.eclipse.wst.common.project.facet.core.xml
?????文件??????????49??2017-05-16?09:08??WebSocketDemo\.settings\org.eclipse.wst.jsdt.ui.superType.container
?????文件???????????6??2017-05-16?09:08??WebSocketDemo\.settings\org.eclipse.wst.jsdt.ui.superType.name
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\WebContent\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\WebContent\meta-INF\
?????文件??????????25??2017-05-16?09:08??WebSocketDemo\WebContent\meta-INF\MANIFEST.MF
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\WebContent\WEB-INF\
?????目錄???????????0??2017-05-16?09:09??WebSocketDemo\WebContent\WEB-INF\lib\
?????文件?????????401??2017-05-16?09:08??WebSocketDemo\WebContent\WEB-INF\web.xml
?????文件????????1921??2017-05-16?09:08??WebSocketDemo\WebContent\index.jsp
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\build\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\build\classes\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\build\classes\com\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\build\classes\com\cn\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\build\classes\com\cn\angell\
?????文件????????3229??2017-05-16?09:08??WebSocketDemo\build\classes\com\cn\angell\WebSocketDemo.class
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\src\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\src\com\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\src\com\cn\
?????目錄???????????0??2017-05-16?09:08??WebSocketDemo\src\com\cn\angell\
?????文件????????3509??2017-05-16?09:08??WebSocketDemo\src\com\cn\angell\WebSocketDemo.java