Question

I have a server which takes a request for a WSDL and sends back the WSDL’s XML line by line. I know the request is being received and processed correctly because I have the server printing out the XML to the console as it’s writing to the server socket. My problem right now is my client app is supposed to be reading in the xml and then printing out method signatures using the xml. I’m going to use DOM / DocumentBuilder to get the parts of the method signature(s) from the WSDL, but I need to first put the lines read in into a file. How can I do this? Currently I’m trying to do it this way:

        //request WSDL from server
        System.out.println("Client requesting \"MathServices?wsdl\"...");
        socketWriter.write("GET MathServices?wsdl");
        socketWriter.close();

        //read XML response into file       
        try {
            File wsdlXML = new File("MathServices.xml");
            FileOutputStream wsdlXmlWriter = new FileOutputStream(wsdlXML);

            String xmlLine;
            while((xmlLine = socketReader.readLine()) != null){
                wsdlXmlWriter.write(xmlLine.getBytes());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

But am getting this error:

Client requesting “MathServices?wsdl”…
java.net.SocketException: socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
at java.io.InputStreamReader.read(InputStreamReader.java:167)
at java.io.BufferedReader.fill(BufferedReader.java:136)
at java.io.BufferedReader.readLine(BufferedReader.java:299)
at java.io.BufferedReader.readLine(BufferedReader.java:362)
at client.Client.main(Client.java:50)

EDIT: server code

package server;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Scanner;

public class RequestHandler extends Thread {

    Object block;
    ServerSocket serverSocket;
    BufferedReader socketReader;
    PrintWriter socketWriter;

    public RequestHandler(Object block, ServerSocket serverSocket){
        this.block = block;
        this.serverSocket = serverSocket;
    }

    @Override
    public void run() {
        try{
            System.out.println("Waiting for connection...");
            Socket clientSocket = serverSocket.accept();
            System.out.println("Connection made.");

            synchronized(block){
                System.out.print("Notifying server thread...");
                block.notify();
                System.out.println("...done");
                System.out.println();
            }

            System.out.println("Setting up streams...");
            socketReader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));            
            socketWriter = new PrintWriter(clientSocket.getOutputStream(), true);
            System.out.println("Reading request");

            String input;
            while((input = socketReader.readLine()) != "\n"){
                //System.out.println("Input: " +input);

                if(input.startsWith("GET")){
                    System.out.println("GET received.");
                    getResource(input);
                }
            }

            socketWriter.close();
            socketReader.close();
            clientSocket.close();

            System.out.println("Streams closed.");
        }catch(IOException e){
            System.out.println("IOException!");
            e.printStackTrace();
        }
    }

    public void getResource(String getRequest){
        String[] parts = getRequest.split("\\s+");
        String filename = parts[1].substring(1);

        if(filename.equals("MathServices?wsdl")){
            filename = "MathServices.wsdl";
        }
        System.out.println(filename);
        File resource = new File(filename);             
        sendResponse(resource, 1);
    }

    public void sendResponse(File resource, int type){
        System.out.println(resource.getAbsolutePath());

        Scanner fileReader;

        try {
            fileReader = new Scanner(resource);

            while(fileReader.hasNext()){
                String line = fileReader.nextLine();
                System.out.println(line);
                socketWriter.println(line);
            }
            socketWriter.println("\n");
            System.out.println("end of response");
            socketWriter.close();

        } catch (FileNotFoundException e) {
            System.out.println("File not found!");
            e.printStackTrace();
        }
    }

}

Answer 1

It looks like you are closing the Socket before reading from socketReader. You must fully read the results from that object before closing the Socket. Is this all of the code? You could also try adding socketWriter.flush() prior to closing it.

Edit:

I noticed that you are sending a GET request to the server, presumably intending to issue an HTTP GET? If so your request is malformed. Try this:

socketWriter.write("GET /MathServices?wsdl HTTP/1.1\r\n\r\n");

You would probably be better off using java.net.URLConnection or Apache HttpClient for this task.