Java Learning Note 53 (Network Programming: TCP protocol Case)

A simple case

Client:

 Packagedemo;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;ImportJava.net.Socket; Public classTCPClient { Public Static voidMain (string[] args)throwsIOException {Socket Socket=NewSocket ("127.0.0.1", 7000); OutputStream out=Socket.getoutputstream (); Out.write ("Hello". GetBytes ()); InputStream in=Socket.getinputstream (); byte[] data =New byte[1024]; intLen =in.read (data); System.out.println (NewString (data, 0, Len));    Socket.close (); }}

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Server-side:

 Packagedemo;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;ImportJava.net.ServerSocket;ImportJava.net.Socket; Public classTCPServer { Public Static voidMain (string[] args)throwsIOException {serversocket server=NewServerSocket (7000); Socket Socket=server.accept (); InputStream in=Socket.getinputstream (); byte[] data =New byte[1024]; intLen =in.read (data); System.out.println (NewString (data, 0, Len)); OutputStream out=Socket.getoutputstream (); Out.write (Receive. GetBytes ());        Socket.close ();    Server.close (); }}

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Start the server side, then start the client, server-side print: Hello, and then the client prints: Received

Note that the flow object is differentiated here

Next in this case based on a picture upload case

The essence of image upload is file copy

Client:

 PackageDemo1;ImportJava.io.FileInputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;ImportJava.net.Socket; Public classTCPClient { Public Static voidMain (string[] args)throwsIOException {Socket Socket=NewSocket ("127.0.0.1", 7000); OutputStream out=Socket.getoutputstream (); FileInputStream FIS=NewFileInputStream ("D:\\666.jpeg"); intLen = 0; byte[] bytes =New byte[1024];  while(len = fis.read (bytes))! =-1) {out.write (bytes,0, Len);        } socket.shutdownoutput (); //server-side read-1, does not terminate, call this method can terminateInputStream in =Socket.getinputstream (); Len=in.read (bytes); System.out.println (NewString (Bytes, 0, Len));        Fis.close ();    Socket.close (); }}

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Server-side:

 PackageDemo1;ImportJava.io.File;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.net.ServerSocket;ImportJava.net.Socket;ImportJava.util.Random; Public classTCPServer { Public Static voidMain (string[] args)throwsIOException {serversocket server=NewServerSocket (7000); Socket Socket=server.accept (); InputStream in=Socket.getinputstream (); File Upload=NewFile ("D:\\upload"); if(!upload.exists ())        {Upload.mkdirs (); } String filename= System.currenttimemillis () +NewRandom (). Nextint (999999) + ". JPEG"; FileOutputStream Fos=NewFileOutputStream (upload + file.separator +filename); //here is the problem of dealing with the names of pictures        byte[] bytes =New byte[1024]; intLen = 0;  while(len = in.read (bytes))! =-1) {fos.write (bytes,0, Len); } socket.getoutputstream (). Write ("Upload succeeded". GetBytes ());        Fos.close ();        Socket.close ();    Server.close (); }}

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If multiple clients are uploading together, a multi-threading technique is required, with each client occupying one thread

Client does not need to modify

Server-side:

 PackageDemo1;Importjava.io.IOException;ImportJava.net.ServerSocket;ImportJava.net.Socket; Public classTCPServer { Public Static voidMain (string[] args)throwsIOException {serversocket server=NewServerSocket (7000);  while(true) {Socket Socket=server.accept (); NewThread (NewUpload (socket)). Start (); }    }}

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 PackageDemo1;ImportJava.io.File;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.net.ServerSocket;ImportJava.net.Socket;ImportJava.util.Random; Public classUploadImplementsRunnable {Privatesocket socket;  PublicUpload (socket socket) { This. Socket =socket; }     Public voidrun () {Try{InputStream in=Socket.getinputstream (); File Upload=NewFile ("D:\\upload"); if(!upload.exists ())            {Upload.mkdirs (); } String filename= System.currenttimemillis () +NewRandom (). Nextint (999999) + ". JPEG"; FileOutputStream Fos=NewFileOutputStream (upload + file.separator +filename); //here is the problem of dealing with the names of pictures            byte[] bytes =New byte[1024]; intLen = 0;  while(len = in.read (bytes))! =-1) {fos.write (bytes,0, Len); } socket.getoutputstream (). Write ("Upload succeeded". GetBytes ());            Fos.close ();        Socket.close (); } Catch(IOException ex) {System.out.println (ex); }    }}

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Java Learning Note 53 (Network Programming: TCP protocol Case)