1.兩種方式，一種使用tomcat的websocket實現，一種使用spring的websocket
2.tomcat的方式需要tomcat 7.x，JEE7的支持。
3.spring與websocket整合需要spring 4.x，并且使用了socketjs，對不支持websocket的瀏覽器可以模擬websocket使用
使用這種方式無需別的任何配置，只需服務端一個處理類，
服務器端代碼
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("已連接"); } @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("給一個人", jsonTo.get("To").toString()); }else{ sendMessageAll("給所有人"); } } @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; } } 客戶端js
var websocket = null; var username = localStorage.getItem("name"); //判斷當前瀏覽器是否支持WebSocket if ('WebSocket' in window) { websocket = new WebSocket("ws://" + document.location.host + "/WebChat/websocket/" + username + "/"+ _img); } else { alert('當前瀏覽器 Not support websocket') } //連接發生錯誤的回調方法 websocket.onerror = function() { setMessageInnerHTML("WebSocket連接發生錯誤"); }; //連接成功建立的回調方法 websocket.onopen = function() { setMessageInnerHTML("WebSocket連接成功"); } //接收到消息的回調方法 websocket.onmessage = function(event) { setMessageInnerHTML(event.data); } //連接關閉的回調方法 websocket.onclose = function() { setMessageInnerHTML("WebSocket連接關閉"); } //監聽窗口關閉事件，當窗口關閉時，主動去關閉websocket連接，防止連接還沒斷開就關閉窗口，server端會拋異常。 window.onbeforeunload = function() { closeWebSocket(); } //關閉WebSocket連接 function closeWebSocket() { websocket.close(); } 發送消息只需要使用websocket.send(“發送消息”)，就可以觸發服務端的onMessage()方法，當連接時，觸發服務器端onOpen()方法，此時也可以調用發送消息的方法去發送消息。關閉websocket時，觸發服務器端onclose()方法，此時也可以發送消息，但是不能發送給自己，因為自己的已經關閉了連接，但是可以發送給其他人。
WebSocketConfig.java
這個類是配置類，所以需要在spring mvc配置文件中加入對這個類的掃描，第一個addHandler是對正常連接的配置，第二個是如果瀏覽器不支持websocket，使用socketjs模擬websocket的連接。
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
這個類的作用就是在連接成功前和成功后增加一些額外的功能，Constants.java類是一個工具類，兩個常量。
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區分WebSocketHandler，以便定向發送消息 String userName = * (String) session.getAttribute(Constants.SESSION_USERNAME); if * (userName==null) { userName="default-system"; } * attributes.put(Constants.WEBSOCKET_USERNAME,userName); * * } } */ //使用userName區分WebSocketHandler，以便定向發送消息(使用shiro獲取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
這個類是對消息的一些處理，比如是發給一個人，還是發給所有人，并且前端連接時觸發的一些動作
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;// 這個會出現性能問題，最好用Map來存儲，key用userid private static Logger logger = Logger.getLogger(ChatMessageHandler.class); static { users = new ArrayList<WebSocketSession>(); } /** * 連接成功時候，會觸發UI上onopen方法 */ @Override public void afterConnectionEstablished(WebSocketSession session) throws Exception { System.out.println("connect to the websocket success......"); users.add(session); // 這塊會實現自己業務，比如，當用戶登錄后，會把離線消息推送給用戶 // TextMessage returnMessage = new TextMessage("你將收到的離線"); // session.sendMessage(returnMessage); } /** * 在UI在用js調用websocket.send()時候，會調用該方法 */ @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { sendMessageToUsers(message); //super.handleTextMessage(session, message); } /** * 給某個用戶發送消息 * * @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; } } } /** * 給所有在線用戶發送消息 * * @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，同時需要增加對WebSocketConfig.java類的掃描，并且增加
xmlns:websocket="http://www.springframework.org/schema/websocket" http://www.springframework.org/schema/websocket <a target="_blank" href="http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd" rel="external nofollow" >http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd</a>
客戶端
<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(); //調用后臺handleTextMessage方法 websocket.send(msg); } else { alert("連接失敗!"); } }); </script> 注意導入socketjs時要使用地址全稱，并且連接使用的是http而不是websocket的ws
總結
以上所述是小編給大家介紹的java 實現websocket的兩種方式實例詳解，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對VeVb武林網網站的支持！
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