Java Simple TCP File transfer

Service Side

 PackageTCP;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;Importjava.net.InetSocketAddress;ImportJava.net.ServerSocket;ImportJava.net.Socket; Public classTcp_file_server { Public Static voidMain (string[] args)throwsException {/*** Create service End sockets*/ServerSocket SS=NewServerSocket (); /*** Bind specified port*/Ss.bind (NewInetsocketaddress (12345)); System.out.println ("" The network disk begins to run ""); /*** Listen and accept the client socket connection and return a socket*/                /*** Continue to receive the information sent by the client and give it to the thread processing*/         while(true) {Socket Socket=ss.accept (); NewThread (NewUpLoad (socket)). Start (); }    }}classUpLoadImplementsrunnable{PrivateSocket socket =NULL;  PublicUpLoad (socket socket) { This. Socket =socket; } @Override Public voidrun () {OutputStream out=NULL; Try {            //Create a file input stream to receive the file stream in the client's socketInputStream in =Socket.getinputstream (); /*** Get filename length * file format: File name Length (number) \r\ file name \ r \ n file contents \ r \ n * Get file name-read the length of the file name before the first carriage return line and read The length of the byte is the file name * Read data until the first carriage return is encountered * Every time you read a byte from the stream into a string to put it on line as long as line is not \ r \ n The end repeats the process /c2>*/String line1= ""; byte[] By1 =New byte[1];  while(!line1.endswith ("\ r \ n") {in.read (by1); String Str=NewString (by1); Line1+=str; }            /*** 1. Read length, minus \ r \ n is the length of the file name * 2.PARSEINT (): The function is to convert the parsed string into an integer.             * 3.substring (): Returns a new string that is a substring of this string. */            intLen1 = Integer.parseint (line1.substring (0, Line1.length ()-2)); /*** 1. Read file name * 2. Create a byte array of equal length and file name to hold the file name * 3.read (data): reads a certain number of bytes from the input stream and stores it in a buffered The data array in the area array data, how much content is read in the in input stream, and the contents are stored in the data array*/            byte[] data =New byte[LEN1];            In.read (data); String FileName=NewString (data); //get file content byte lengthString line2 = ""; byte[] By2 =New byte[1];  while(!line2.endswith ("\ r \ n") {in.read (by2); String Str=NewString (BY2); Line2+=str; }            intLen2 = Integer.parseint (line2.substring (0, Line2.length ()-2)); //Create the output stream of the input file, specify the file export addressString Path = "e:/" +FileName; out=NewFileOutputStream (path); //get file Content bytes//Flow Docking            byte[] By3 =New byte[Len2];            In.read (BY3);                        Out.write (BY3); System.out.println ("Receive from" +socket.getinetaddress (). Gethostaddress () + "uploaded file" +path); } Catch(IOException e) {e.printstacktrace (); }finally {            //Close Resource//turn off the output stream            Try {                if(Out! =NULL) {out.close (); }            } Catch(IOException e) {e.printstacktrace (); }finally{ out=NULL; }            //Close Socket            Try {                if(Socket! =NULL) {socket.close (); }            } Catch(IOException e) {e.printstacktrace (); }finally{Socket=NULL; }        }    }}

Client

 PackageTCP;ImportJava.io.File;ImportJava.io.FileInputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;Importjava.net.InetSocketAddress;ImportJava.net.Socket;ImportJava.util.Scanner; Public classtcp_file_client { Public Static voidMain (string[] args) {Scanner scan=NULL; InputStream in=NULL; Socket Socket=NULL; Try {            /*** 1. Scan console Receive File pathname * Create a file reference, point to a new file object, and give the address*/System.out.println ("Please enter the path of the file to be transferred:"); Scan=NewScanner (system.in); String Path=Scan.nextline (); File File=NewFile (path); /*** 2. Determine if the file is a text file instead of a folder and the path exists * EXISTS (): Determine if the file exists * Isfile (): Determine if the file is /c7>*/            if(File.exists () &&File.isfile ()) {                                /*** 3. Create a file input stream, send a file * The contents of the file input are placed in the files*/inch=Newfileinputstream (file); /*** Socket This class implements a client socket (also known as a "socket").                 Sockets are the endpoints of communication between two machines. * 4. Create a client socket*/Socket=NewSocket (); //inetsocketaddress inets = new Inetsocketaddress ("127.0.0.1", 12345);                                /*** 5. Connect the TCP server * determine the IP and port number on the service side*/Socket.connect (NewInetsocketaddress ("127.0.0.1", 12345)); /*** 6. Get the output stream to the client * OutputStream getoutputstream () *                  Returns the output stream for this socket. */OutputStream out=Socket.getoutputstream (); /*** 7. Send a file to the server * itself defines a protocol to solve the sticky packet phenomenon, get the file name * 7.1. We first read the contents of the file and put it                 Inside * 7.2. Read the file name File.getname () * 7.3. Convert the file name to Byte File.getname (). GetBytes ()                 * 7.4. Gets the length of the byte of the file name File.getname (). GetBytes (). length * 7.5. Add \ r \ n as an identifier after the filename length */                //Send to server [filename byte length \ r \ n]Out.write ((File.getname (). GetBytes (). length + "\ r \ n"). GetBytes ()); //Send to server [filename bytes]Out.write (File.getname (). GetBytes ()); //Send to server [file byte length \ r \ n]Out.write ((file.length () + "\ r \ n"). GetBytes ()); //send [File byte contents] to server                byte[] data =New byte[1024]; inti = 0;  while((i = in.read (data))! =-1) {out.write (data,0, i); }                            }Else{System.out.println ("File does not exist or a file ~ ~"); }        } Catch(Exception e) {e.printstacktrace (); }finally {            /*** Turn off scanner, file input stream, socket * Socket to decorate the output stream, so do not close the output stream*/            if(Scan! =NULL) {scan.close (); }            Try {                if(In! =NULL) {in.close (); }            } Catch(IOException e) {e.printstacktrace (); }finally {                //force the input stream to be emptyin =NULL; }            Try {                if(Socket! =NULL) {socket.close (); }            } Catch(IOException e) {e.printstacktrace (); }finally {                //Force release SocketSocket =NULL; }} System.out.println ("File Transfer Complete"); }}

Java Simple TCP File transfer