本文实例为大家分享了java WebSocket实现聊天消息推送功能的具体代码，供大家参考，具体内容如下
环境：
JDK.1.7.0_51
apache-tomcat-7.0.53
java jar包：tomcat-coyote.jar、tomcat-juli.jar、websocket-api.jar
ChatAnnotation消息发送类：
import java.io.IOException;import java.util.HashMap;import java.util.Map;import java.util.concurrent.atomic.AtomicInteger; 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; import org.apache.juli.logging.Log;import org.apache.juli.logging.LogFactory; import com.util.HTMLFilter; /** * WebSocket 消息推送服务类 * @author 胡汉三 * * 2014-11-18 下午7:53:13 */@ServerEndpoint(value = "/websocket/chat")public class ChatAnnotation { private static final Log log = LogFactory.getLog(ChatAnnotation.class); private static final String GUEST_PREFIX = "Guest"; private static final AtomicInteger connectionIds = new AtomicInteger(0); private static final Map<String,Object> connections = new HashMap<String,Object>(); private final String nickname; private Session session; public ChatAnnotation() { nickname = GUEST_PREFIX + connectionIds.getAndIncrement(); } @OnOpen public void start(Session session) { this.session = session; connections.put(nickname, this); String message = String.format("* %s %s", nickname, "has joined."); broadcast(message); } @OnClose public void end() { connections.remove(this); String message = String.format("* %s %s", nickname, "has disconnected."); broadcast(message); } /** * 消息发送触发方法 * @param message */ @OnMessage public void incoming(String message) { // Never trust the client String filteredMessage = String.format("%s: %s", nickname, HTMLFilter.filter(message.toString())); broadcast(filteredMessage); } @OnError public void onError(Throwable t) throws Throwable { log.error("Chat Error: " + t.toString(), t); } /** * 消息发送方法 * @param msg */ private static void broadcast(String msg) { if(msg.indexOf("Guest0")!=-1){ sendUser(msg); } else{ sendAll(msg); } } /** * 向所有用户发送 * @param msg */ public static void sendAll(String msg){ for (String key : connections.keySet()) { ChatAnnotation client = null ; try { client = (ChatAnnotation) connections.get(key); synchronized (client) { client.session.getBasicRemote().sendText(msg); } } catch (IOException e) { log.debug("Chat Error: Failed to send message to client", e); connections.remove(client); try { client.session.close(); } catch (IOException e1) { // Ignore } String message = String.format("* %s %s", client.nickname, "has been disconnected."); broadcast(message); } } } /** * 向指定用户发送消息 * @param msg */ public static void sendUser(String msg){ ChatAnnotation c = (ChatAnnotation)connections.get("Guest0"); try { c.session.getBasicRemote().sendText(msg); } catch (IOException e) { log.debug("Chat Error: Failed to send message to client", e); connections.remove(c); try { c.session.close(); } catch (IOException e1) { // Ignore } String message = String.format("* %s %s", c.nickname, "has been disconnected."); broadcast(message); } }}HTMLFilter工具类：
/** * HTML 工具类 * * @author 胡汉三 */public final class HTMLFilter { public static String filter(String message) { if (message == null) return (null); char content[] = new char[message.length()]; message.getChars(0, message.length(), content, 0); StringBuilder result = new StringBuilder(content.length + 50); for (int i = 0; i < content.length; i++) { switch (content[i]) { case '<': result.append("<"); break; case '>': result.append(">"); break; case '&': result.append("&"); break; case '"': result.append("""); break; default: result.append(content[i]); } } return (result.toString()); }}页面：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%> <?xml version="1.0" encoding="UTF-8"?><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"><head> <title>测试</title> <style type="text/css"> input#chat { width: 410px } #console-container { width: 400px; } #console { border: 1px solid #CCCCCC; border-right-color: #999999; border-bottom-color: #999999; height: 170px; overflow-y: scroll; padding: 5px; width: 100%; } #console p { padding: 0; margin: 0; } </style> <script type="text/javascript"> var Chat = {}; Chat.socket = null; Chat.connect = (function(host) { if ('WebSocket' in window) { Chat.socket = new WebSocket(host); } else if ('MozWebSocket' in window) { Chat.socket = new MozWebSocket(host); } else { Console.log('Error: WebSocket is not supported by this browser.'); return; } Chat.socket.onopen = function () { Console.log('Info: WebSocket connection opened.'); document.getElementById('chat').onkeydown = function(event) { if (event.keyCode == 13) { Chat.sendMessage(); } }; }; Chat.socket.onclose = function () { document.getElementById('chat').onkeydown = null; Console.log('Info: WebSocket closed.'); }; Chat.socket.onmessage = function (message) { Console.log(message.data); }; }); Chat.initialize = function() { if (window.location.protocol == 'http:') { Chat.connect('ws://' + window.location.host + '/socket2/websocket/chat'); } else { Chat.connect('wss://' + window.location.host + '/socket2/websocket/chat'); } }; Chat.sendMessage = (function() { var message = document.getElementById('chat').value; if (message != '') { Chat.socket.send(message); document.getElementById('chat').value = ''; } }); var Console = {}; Console.log = (function(message) { var console = document.getElementById('console'); var p = document.createElement('p'); p.style.wordWrap = 'break-word'; p.innerHTML = message; console.appendChild(p); while (console.childNodes.length > 25) { console.removeChild(console.firstChild); } console.scrollTop = console.scrollHeight; }); Chat.initialize(); document.addEventListener("DOMContentLoaded", function() { // Remove elements with "noscript" class - <noscript> is not allowed in XHTML var noscripts = document.getElementsByClassName("noscript"); for (var i = 0; i < noscripts.length; i++) { noscripts[i].parentNode.removeChild(noscripts[i]); } }, false); </script></head><body><div><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable Javascript and reload this page!</h2></div><div> <p> <input type="text" placeholder="请输入内容" id="chat" /> </p> <div id="console-container"> <div id="console"/> </div></div></body></html>可指定发送给某个用户，也可全部发送，详情见ChatAnnotation类的broadcast方法。
程序发布时记得删除tomcat-coyote.jar、tomcat-juli.jar、websocket-api.jar这三个jar包在启动Tomcat。
程序截图，Guest0用户发送信息的信息，在后台进行了判断只发送给自己：
Guest1：
Guest2：
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。