Multiple clients uploading files

Multithreading issues in TCP usage

1, the problem: The General TCP program in the processing of multi-threaded situations, there will be problems:

Such as: There is a, b two clients to send data to the server, when a client connection is later acquired by the service side, the service side to execute the specific process; At this point the B client connects, only waits.

Because the server has not finished processing the a client's request, there is a loop back to execute the next accept method. Therefore, the B client object is not available temporarily.

2, solve the idea:
The best service side is to encapsulate each client in a separate thread so that multiple client requests can be processed at the same time.

Program code:

　Client:

1 classpicsend{2 3  Public Static voidMain (String args[]) {4         Try {5Socket s =NewSocket (Inetaddress.getlocalhost (). Gethostaddress (), 11001    );6FileInputStream ins =NewFileInputStream ("Test/1.jpg");7OutputStream out =S.getoutputstream ();8             //BufferedReader bufr = new BufferedReader (New InputStreamReader (S.getinputstream ()));9             byte[] buf =New byte[1024];Ten             intLen = 0; One              while(len = Ins.read (BUF))! =-1){ AOut.write (buf, 0, Len); -             } -              theS.shutdownoutput ();//end image upload, read server return information -              - //String str = bufr.readline (); - //System.out.println (str); +InputStream in =S.getinputstream (); -             byte[] bytes =New byte[1024]; +             intLENS =in.read (bytes); ASYSTEM.OUT.PRINTLN ("server returned:" +NewString (bytes,0, Lens)); at              - ins.close (); - s.close (); -                      -}Catch(Exception e) { -             //TODO auto-generated Catch block in e.printstacktrace (); -         } to          +     } -  the  *}

Server-side:

1 classthreadserver{2      Public Static voidMain (String args[]) {3         Try {4ServerSocket Server =NewServerSocket (10001);5             6              while(true){//Note: True in while is because the accept method is a blocking method and does not cause the program to loop indefinitely7Socket s =server.accept ();8                 NewThread (NewPicthread (s)). Start ();9             }Ten}Catch(IOException e) { One             //TODO auto-generated Catch block A e.printstacktrace (); -         }         -          the     } - } -  - classPicthreadImplementsrunnable{//encapsulating the client, implementing a single thread +     PrivateSocket S; - Picthread (Socket s) { +          This. S =s; A          at     } -      -      Public voidRun () {//writes the client to the code in the Run method -         Try { -InputStream in =S.getinputstream (); -FileOutputStream Fout =NewFileOutputStream ("Thread.jpg"); in             byte[] buf =New byte[1024]; -             intLen = 0; to              while((Len=in.read (BUF))!=-1){ +Fout.write (buf,0, Len); -             } the              *OutputStream out =S.getoutputstream (); $             byte[] bytes = "Image upload succeeded". GetBytes ();Panax Notoginseng out.write (bytes); -              the fout.close (); + s.close (); A              the}Catch(Exception e) { +             //TODO auto-generated Catch block - e.printstacktrace (); $         } $          -     } -     

This enables multiple clients to send files to the server.

3. Design Highlights

In this TCP program, it is very clever to encapsulate each client in a single thread, so that the server has the ability to handle multithreading, which is very useful in development.

　　

    New ServerSocket (10001);                          while (true) {                  = server.accept ();                 New Thread (new  Picthread (s)). Start ();    

Multiple clients uploading files