适用于Android的多线程Web服务器

Question

I'm developing a multithreaded web server for an android app and I've some problems with a page that uses an external .css file, and a .js file, but only with Google Chrome! With Firefox and Opera the page is rendered fine, with Google Chrome sometimes the .css is loaded, sometimes the .js, sometime both or neither.

This is my app's structure:

WebServer.java

class WebServer implements Runnable{
protected boolean ON;

public void start(){
            if(!ON){
            ON=true;
            thread=new Thread(this,"WebServer");
            thread.start(); }}

public void run(){
while(ON){
listenSocket = new ServerSocket(port);
Socket connectionSocket = listenSocket.accept();
Thread t = new Thread(new Client(connectionSocket));
t.start();
listenSocket.close();}
}}

Client.java

class Client implements Runnable {
public void start(){
        thread=new Thread(this,"Client");
        thread.start();}

public void run(){
//parse the request and send a file
}
}

myApp.java

public class myApp extends Activity{

onCreate(){
WebServer ws=new WebServer(8080);
}

onClick(){
...
ws.start();
}}

When I click a button on the activity, it call webserver.start(); In my opinion google chrome sends more requests concurrently and there's a problem with threads... Can you help me?

[EDIT] I had forgotten to write the loop in the run() method in the question

[EDIT 2] I just tried with an other pc, and there are problems also with firefox..

Answer 1

There is a general misunderstanding of the thread mechanism in your code.

A runnable has to override run. Not start. The run() method of the runnable will be called when the nesting thread will be started. In other words, the start method of your client will never be used, and hope fully, as it would create a thread inside a thread.. not very usefull.

Redesign your webser so that, :

• it's start method starts a new nesting thread as you did
• it's run method does the following
  • your webserver binds to a port
  • in a loop : accept new connections and start new client thread for each.
  • the loop could be controlled by a boolean flag that you could rise to stop the server (ON would fit, even if the name of this variable doesn't follow java naming conventions and is rather poor semanticly speaking)

then each client would, in it's run (no more start method) :

• read data from socket input stream
• reply on socket outputstream
• briefly, implement http protocole.

You could find some java code to inspire you on the web , some examples are well documented . Also, you could consider using java.nio package that is maybe less effective for a single request but much more effective at handling massive multiple connections. But code is harder.

You should consider reading more about runnables and also consider reading some stuff about synchronized key word to ensure that your web server doesn't start twice a connection for the same client or get confused in case of simultaneous requests.

Regards, Stéphane