Java Basic Knowledge Network programming (TCP practice)

Exercise: Copying text

Practice requirements: To send a client's file content to the server, on the server side of the data stored in a file. equivalent to copying files.

Importjava.io.*;ImportJava.net.*;class txtcopytestclient{ Public Static void Main(string[] args)throwsException {Socket s=NewSocket ("192.168.1.6",10003); BufferedReader bur=NewBufferedReader (NewInputStreamReader (NewFileInputStream ("Client.txt")));//bufferedwriter buwout=new BufferedWriter (New OutputStreamWriter (S.getoutputstream ()));PrintWriter pw=NewPrintWriter (S.getoutputstream (),true); String line=NULL; while((Line=bur.readline ())! =NULL) {pw.println (line);        } s.shutdownoutput (); BufferedReader burin=NewBufferedReader (NewInputStreamReader (S.getinputstream ()));        String Str=burin.readline ();        System.out.println (str);        Bur.close ();    S.close (); }}class txtcopytestserver{ Public Static void Main(string[] args)throwsException {ServerSocket ss=NewServerSocket (10003);        Socket s=ss.accept (); BufferedReader burin=NewBufferedReader (NewInputStreamReader (S.getinputstream ())); PrintWriter pw=NewPrintWriter (NewFileOutputStream ("Server.txt"),true); String line=NULL; while((Line=burin.readline ())! =NULL) {pw.println (line);        } pw.close (); PrintWriter pwout=NewPrintWriter (S.getoutputstream (),true); Pwout.println ("Upload succeeded");        S.close ();    Ss.close (); }}

Exercise 2: Uploading pictures

Import Java.io.*;import java.net.*;class picclient { Public Static void Main(string[] args) throws Exception {Socket s=NewSocket ("192.168.1.114",10003); FileInputStream fis=NewFileInputStream ("Pictest.jpg"); OutputStream Os=s.getoutputstream ();byte[] buf=New byte[1024x768];intlen=0; while((Len=fis.read (BUF))!=-1) {Os.write (buf,0, Len);        } s.shutdownoutput (); InputStream is=s.getinputstream ();byte[] re=New byte[1024x768];intLength= is. read (re); String str=NewString (Re,0, length); System. out. println (str);        Fis.close ();    S.close (); }}class picserver{ Public Static void Main(string[] args) throws Exception {ServerSocket ss=NewServerSocket (10003);        Socket s=ss.accept (); InputStream is=s.getinputstream (); FileOutputStream fos=NewFileOutputStream ("Serverpic.jpg");byte[] buf=New byte[1024x768];intlen=0; while((len= is. Read (BUF))!=-1) {Fos.write (buf,0, Len);        } outputstream Os=s.getoutputstream (); Os.write ("Upload succeeded". GetBytes ());        S.close ();    Ss.close (); }}

Exercise 3: Client uploads pictures concurrently

Import Java.io.*;import Java.net.*;class uploadbythreadclient{ Public Static void Main(string[] args) throws Exception {if(args.length!=1) {System. out. println ("Please select a JPG image");return; } File file=NewFile (args[0]);if(!        (File.exists () &&file.isfile ())) {System. out. println ("There is a problem with the file, either a complement exists, or it is not a file");return; }if(!file.getname (). EndsWith (". jpg")) {System. out. println ("Picture format is wrong, please re-select");return; }if(File.length () >1024x768*1024x768*5) {System. out. println ("The file is too large.);return; } Socket s =NewSocket ("192.168.1.114",10003); FileInputStream FIS =NewFileInputStream ("Pictest.jpg"); OutputStream out= S.getoutputstream ();byte[] buf =New byte[1024x768];intLen =0; while((Len=fis.read (BUF))!=-1)        { out. Write (BUF,0, Len); }//Tell the server that the data has been finishedS.shutdownoutput (); InputStreaminch= S.getinputstream ();byte[] Bufin =New byte[1024x768];intnum =inch. read (Bufin); System. out. println (NewString (Bufin,0, num));        Fis.close ();    S.close (); }}class uploadbythreadserver{ Public Static void Main(string[] args) throws Exception {ServerSocket ss=NewServerSocket (10003); while(true) {Socket s=ss.accept ();NewThread (NewAcceptthread (s)). Start (); }}}class Acceptthread implements runnable{PrivateSocket s; Acceptthread (Socket s) { This. s=s; } Public void Run()    {Try{InputStreaminch= S.getinputstream (); String ip=s.getinetaddress (). gethostaddress ();intCount=1; File def=NewFile (ip+"("+count+")"+". jpg"); while(Def.exists ()) {def=NewFile (ip+"("+ (count++) +")"+". jpg"); } FileOutputStream fos =NewFileOutputStream (Def);byte[] buf =New byte[1024x768];intLen =0; while((len=inch. Read (BUF))!=-1) {Fos.write (buf,0, Len); } outputstream out= S.getoutputstream (); out. Write ("Upload succeeded". GetBytes ());            Fos.close ();        S.close (); }Catch(Exception e) {Throw NewRuntimeException ("Upload failed"); }    }}

Exercise 4: Client Concurrent Login

Import Java.io.*;import java.net.*; class loginclient{     Public Static voidMain (string[] args) throws Exception {Socket s=NewSocket ("192.168.1.6",100010); BufferedReader bur=NewBufferedReader (NewInputStreamReader (system.in)); PrintWriter pw=NewPrintWriter (S.getoutputstream (),true); BufferedReader burin=NewBufferedReader (NewInputStreamReader (S.getinputstream ())); for(intI=0;i<3; i++) {String user=bur.readline ();if(user==NULL) Break;            PW.PRINTLN (user);            String Info=burin.readline (); System.out.println ("The Feedback information is:"+info);if(Info.contains ("Welcome") {System.out.println ("Successful Landing"); Break;        }} bur.close ();    S.close (); }} class loginserver{     Public Static voidMain (string[] args) throws Exception {ServerSocket ss=NewServerSocket (100010); while(true) {Socket s=ss.accept (); System.out.println ("Connection succeeded");NewThread (NewUserloginthread (s)). Start (); }    }} class userloginthread implements Runnable{    PrivateSocket s; Userloginthread (Socket s) { This. s=s; } Public voidRun () {Try{BufferedReader burin=NewBufferedReader (NewInputStreamReader (S.getinputstream ())); for(intI=0;i<3; i++) {String user=burin.readline (); System.out.println ("username sent to:"+user);if(user==NULL) {System.out.println ("is empty"+user); Break; } BufferedReader bur=NewBufferedReader (NewFileReader ("User.txt")); String line=NULL;Booleanflag=false; while((Line=bur.readline ())! =NULL) {System.out.println ("User name found:"+line);if(line.equals (user)) {flag=true; Break; }                }if(flag) {PrintWriter pw=NewPrintWriter (S.getoutputstream (),true); Pw.println (user+"Welcome you!" "); S.close (); Break; }Else{PrintWriter pw=NewPrintWriter (S.getoutputstream (),true); Pw.println ("Please enter the correct user name");            } bur.close ();        } s.close (); }Catch(Exception e) {Throw NewRuntimeException ("Login Failed"); }    }}

Java Basic Knowledge Network programming (TCP practice)