Java WebSocket implements chat message push function

This article shares the specific code of java WebSocket to implement chat message push function for your reference. The specific content is as follows

environment:

JDK.1.7.0_51

apache-tomcat-7.0.53

java jar package: tomcat-coyote.jar, tomcat-juli.jar, websocket-api.jar

ChatAnnotation message sending class:

 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 message push service class* @author Hu Hansan* * 2014-11-18 7:53:13 pm */@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); } /** * Message sending trigger method* @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); } /** * Message sending method* @param msg */ private static void broadcast(String msg) { if(msg.indexOf("Guest0")!=-1){ sendUser(msg); } else{ sendAll(msg); } } /** * Send to all users* @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); } } } /** * Send a message to the specified user* @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 tool class:

 /** * HTML tool class* * @author Hu Hansan*/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()); }}

page:

 <%@ 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>Test</title> <style type="text/css"> input#chat { width: 410px } #console-container { width: 400px; } #console { border: 1px solid #CCCCCC; border-right-color: #99999; border-bottom-color: #99999; 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="Please enter content" id="chat" /> </p> <div id="console-container"> <div id="console"/> </div></div></body></html>

You can specify to send it to a certain user, or you can send it all. For details, see the broadcast method of the ChatAnnotation class.
When publishing the program, remember to delete the three jar packages: tomcat-coyote.jar, tomcat-juli.jar, and websocket-api.jar and start Tomcat.

Program screenshot, Guest0 user sends information, and makes judgments in the background and only sends it to itself:

Guest1:

Guest2:

The above is all the content of this article. I hope it will be helpful to everyone's learning and I hope everyone will support Wulin.com more.