Tomcat下WebSocket最大连接数测试

默认情况下，Tomcat的WebSocket最大连接数为200。

WebSocket后台代码

package com.chat.demo;

/*
*  Licensed to the Apache Software Foundation (ASF) under one or more
*  contributor license agreements.  See the NOTICE file distributed with
*  this work for additional information regarding copyright ownership.
*  The ASF licenses this file to You under the Apache License, Version 2.0
*  (the "License"); you may not use this file except in compliance with
*  the License.  You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0 *
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*  distributed under the License is distributed on an "AS IS" BASIS,
*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*  See the License for the specific language governing permissions and
*  limitations under the License.
*/

import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
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 util.HTMLFilter;

@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 Set<ChatAnnotation> connections =
new CopyOnWriteArraySet<ChatAnnotation>();

private final String nickname;
private Session session;

public ChatAnnotation() {
nickname = GUEST_PREFIX + connectionIds.getAndIncrement();
}

@OnOpen
public void start(Session session) {
this.session = session;
connections.add(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);
}

@OnMessage
public void incoming(String message) {
// Never trust the client
String filteredMessage = String.format("%s: %s",
nickname, message.toString());
broadcast(filteredMessage);
}

@OnError
public void onError(Throwable t) throws Throwable {
System.out.println("Chat Error: " + t.toString());
}

private static void broadcast(String msg) {
for (ChatAnnotation client : connections) {
try {
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);
}
}
}
}

启动Tomcat,注意ws的地址，然后运行测试WebSocket连接数代码

package com.jiafuwei.java.snake;

import java.net.URI;

import javax.websocket.ClientEndpoint;
import javax.websocket.ContainerProvider;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;

@ClientEndpoint
public class WebSocketTest {

private String deviceId;

private Session session;

public WebSocketTest () {

}

public WebSocketTest (String deviceId) {
this.deviceId = deviceId;
}

protected boolean start() {
WebSocketContainer Container = ContainerProvider.getWebSocketContainer();
String uri = "ws://localhost:8028/lhychat/websocket/chat";
System.out.println("Connecting to " + uri);
try {
session = Container.connectToServer(WebSocketTest.class, URI.create(uri));
System.out.println("count: " + deviceId);
} catch (Exception e) {
e.printStackTrace();
return false;
}
return true;
}

public static void main(String[] args) {
for (int i = 1; i< 1000; i++) {
WebSocketTest wSocketTest = new WebSocketTest(String.valueOf(i));
if (!wSocketTest.start()) {
System.out.println("测试结束！");
break;
}
}
}
}

运行结果为每次循环到第200个的时候，测试结束了，WebSocket后台代码开始报错。

如何增加并发数呢，只需在server.xml文件中，增加 maxThreads="300" 这样最大的并发数就变成了300。

<Connector maxConnections="300"  maxThreads="300"  URIEncoding="UTF-8" connectionTimeout="20000" port="8028" protocol="HTTP/1.1" redirectPort="8443" useBodyEncodingForURI="true"/>

参考资料：
http://blog.csdn.net/z915412321/article/details/52261229 http://bbs.csdn.net/topics/390678513