struts2 + websocket 实现web程序网页消息推送。
使用websocket技术实现消息推送到网页效果。
主要说两种，一种是servlet，一种是struts2. 两种方法后台稍微有点区别，交叉没有试过。
初步测试已调通此两种方法。
第一种：
servlet
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.util.ArrayList;
import javax.servlet.http.HttpServletRequest;
import javax.websocket.server.ServerEndpoint;
import org.apache.catalina.websocket.MessageInbound;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;
import org.apache.catalina.websocket.WsOutbound;
public class WebServelt extends WebSocketServlet {
private static final long serialVersionUID = -4853540828121130946L;
private static ArrayList<MyMessageInbound> mmiList = new ArrayList<MyMessageInbound>();
@Override
protected StreamInbound createWebSocketInbound(String str,
HttpServletRequest request) {
return new MyMessageInbound();
}
private class MyMessageInbound extends MessageInbound {
WsOutbound myoutbound;
@Override
public void onOpen(WsOutbound outbound) {
try {
System.out.println("Open Client.");
this.myoutbound = outbound;
mmiList.add(this);
outbound.writeTextMessage(CharBuffer.wrap("Hello!"));
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onClose(int status) {
System.out.println("Close Client.");
mmiList.remove(this);
}
//当服务器端收到信息的时候,就对所有的连接进行遍历并且把收到的信息发送给所有用户
@Override
public void onTextMessage(CharBuffer cb) throws IOException {
System.out.println("Accept Message : " + cb);
for (MyMessageInbound mmib : mmiList) {
CharBuffer buffer = CharBuffer.wrap(cb);
mmib.myoutbound.writeTextMessage(buffer);
mmib.myoutbound.flush();
}
}
@Override
public void onBinaryMessage(ByteBuffer bb) throws IOException {
}
}
}
页面
<!DOCTYPE html>
<html>
<head>
<meta charset=UTF-8>
<title>Tomcat WebSocket Chat</title>
<script>
//建立客户端websocket
var ws = new WebSocket("ws://localhost:8080/Backstage/ws/wsServlet");
//定义ws的一些回调函数
ws.onopen = function() {
};
//当有消息传过来时执行的操作
ws.onmessage = function(message) {
document.getElementById("chatlog").textContent += message.data + "\n";
};
function postToServer() {
ws.send(document.getElementById("msg").value);
document.getElementById("msg").value = "";
}
function closeConnect() {
ws.close();
}
</script>
</head>
<body>
<textarea id="chatlog" readonly></textarea>
<br />
<input id="msg" type="text" />
<button type="submit" id="sendButton" onClick="postToServer()">Send!</button>
<button type="submit" id="sendButton" onClick="closeConnect()">End</button>
</body>
</html>
web.xml
<display-name>Websocket</display-name>
<servlet>
<servlet-name>wsServlet</servlet-name>
<servlet-class>com.backstage.calendar.WebServelt</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>wsServlet</servlet-name>
<url-pattern>/ws/wsServlet</url-pattern>
</servlet-mapping>
效果：
第二种
@ServerEndpoint("/ws/websocket")
public class WebSocketTest {
@OnMessage
public void onMessage(String message,Session session)
throws IOException, InterruptedException
{
System.out.println("***************");
session.getBasicRemote().sendText(" this is message");
int sentMessage = 0;
while(sentMessage < 3){
Thread.sleep(5000);
session.getBasicRemote().sendText(" this is one mess " + sentMessage);
sentMessage++;
}
session.getBasicRemote().sendText(" message send over ");
}
@OnOpen
public void onOpen(){
System.out.println(" client connected ");
}
@OnClose
public void onClose(){
System.out.println(" connection closed ");
}
}
使用@ServerEndpoint("/ws/websocket") 进行访问
html
<!DOCTYPE html>
<html>
<head>
<title>Testing websockets</title>
</head>
<body>
<div>
<input type="submit" value="Start" onclick="start()" />
</div>
<div id="messages"></div>
<script type="text/javascript">
var webSocket;
if ('WebSocket' in window) {
webSocket = new WebSocket("ws://localhost:8080/Backstage/ws/websocket");
} else if ('MozWebSocket' in window) {
webSocket = new MozWebSocket("ws://localhost:8080/websocket");
} else {
alert("js");
webSocket = new SockJS("http://localhost:8080/Origami/sockjs/webSocketServer");
}
webSocket.onerror = function(event) {
onError(event)
};
webSocket.onopen = function(event) {
onOpen(event)
};
webSocket.onmessage = function(event) {
onMessage(event)
};
function onMessage(event) {
document.getElementById('messages').innerHTML
+= '<br />' + event.data;
}
function onOpen(event) {
document.getElementById('messages').innerHTML
= 'Connection established';
}
function onError(event) {
//console.log(event);
//console.log(event.data);
alert(event.data);
}
function start() {
webSocket.send('hello');
return false;
}
</script>
</body>
</html>
效果
Firefox 无法建立到 ws://localhost:8080/Backstage/ws/websocket 服务器的连接。
webSocket = new WebSocket("ws://localhost:8080/Backstage/ws/websocket");
|
报这个错的原因是用了struts2过滤器，web.xml 中配置了 struts2 过滤为 /* ，所以所有的请求都被拦截过去了。
解决办法：
struts.xml 文件中加上
<constant name="struts.action.excludePattern" value="/ws/.*,ws://.*"></constant>
过滤掉ws:// 请求
在此也谢谢参考过的朋友们。上面的例子也是百度出来的资料直接copy过来。由于求解决方案资料搜寻的太多，原链接丢失了。