IO Streams

Can anybody tell me what is wrong with the following client and server code:



public class Client{

     static Socket socket;
     public static void main(String as[]){

          try{
               socket = new Socket("ecomserv",8888);
               DataInputStream dis = new DataInputStream(socket.getInputStream());

               FileWriter fw = new FileWriter(new File("proposal1.doc"));
               int data;
               while((data = dis.read()) != -1          ){
                    fw.write(data);
                    fw.flush();
               }
               fw.close();
          }
          catch(UnknownHostException e){
               System.out.println("Not Connected " + e );
               return;
          }
          catch(IOException ee){
               System.out.println("IO Exception " + ee );
               return;
          }
     }
}


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

public class Server{

     static ServerSocket listen;
     
     static PrintWriter pw;
     static DataInputStream dis;
     


     public static void main(String as[]){
          int data;
          try{
               listen = new ServerSocket(8888);
               Socket socket = listen.accept();
               pw = new PrintWriter(socket.getOutputStream());
               dis = new DataInputStream(socket.getInputStream());
               FileReader fr = new FileReader(new File("proposal1.doc"));
          //     BufferedReader br = new BufferedReader(fr);
               while((data = fr.read()) != -1 ){
                    pw.print(data);
                    pw.flush();
               }
               pw.close();
          }
          catch(Exception e){
               System.out.println("error " + e);
          }
     }
}



I am sending a file from the server to the client.
The file is transferring... but contains only junk... Can anybody explain what is going wrong here??
thankyou

Hi,

DataInputStream dis = new DataInputStream(socket.getInputStream());
// Not a bug, but you don't use DataInputStream specific functionality.
// Plain InputStream will work

int data;
while((data = dis.read()) != -1 ){
        fw.write(data);
// You need to cast data to byte: fw.write((byte)data);
        fw.flush();
// It's not a bug, but it slows you down. You don't really need to
// flush on each byte. I would even wrap FileOutputStream
// into BufferedOutputStream
}

FileReader fr = new FileReader(new File("proposal1.doc"));
//     BufferedReader br = new BufferedReader(fr);
while((data = fr.read()) != -1 ){
     pw.print(data);
// Now, you need to cast data to char
     pw.flush();
}
pw.close();

BTW, why your client and server are not symmetric? Why don't you use OutputStream on server side?
And server doesn't need to open InputStream--client doesn't send anything.
Better server would spawn new Thread upon accept return to serve several clients concurrently.

Regards,
Igor Bazarny,
Brainbench MVP for Java 1
www.brainbench.com                                                         

> Better server would spawn new Thread upon accept return to serve several clients concurrently.
And wrap accept into infinite loop to serve more then one client.

oops!!
here is the modified server code!!

public class Server{

    static ServerSocket listen;

    static DataOutputStream dos;
    static DataInputStream dis;



    public static void main(String as[]){
         int data;
         try{
              listen = new ServerSocket(8888);
              Socket socket = listen.accept();
              dos = new DataOutputStream(socket.getOutputStream());
              //dis = new DataInputStream(socket.getInputStream());
              FileInputStream fis = new FileInputStream(new File("Server.java"));
              int count = 0;
         //     BufferedReader br = new BufferedReader(fr);
              while((data = fis.read()) != -1 ){
                         count++;
                   dos.write(data);
                         dos.flush();
              }
                    System.out.println( "Total number of char written : " + count );
              dos.close();
              fis.close();
         }
         catch(Exception e){
              System.out.println("error " + e);
         }
    }
}

Hi,

I revoke my long comment--after inspection of doc I found that write() has int parameter. But there is still conversion problem in server code: pw.print(data); will convert int to decimal string representation, while you need simply char with correspondent code to be written. Replacing print() by write() should solve the problem.

Oops. One more conversion problem: on client side you read byte from InputStream and write it as char to Writer. That at least unsafe--there is a big range of bytes which will be changed bu such operation.

Compare Viswa's suggestion to your code--it looks like (s)he did it right.

Regards,
Igor Bazarny

Thanks viswa. The code works perfect now

welcome!!
And thanx for the points