java WebSocket 简易聊天消息推送实例方法介绍

java WebSocket 简易聊天消息推送实例方法介绍。

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：

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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：

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/**
* 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：

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<%@ 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 class=”noscript”><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：

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java WebSocket 简易聊天消息推送实例方法介绍

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