Question

Servet Problem: java.io.EOFException

Asked by: asaliu

Hello to all Experts.

I have a java swing Gui giving the servlet a parameter:
----------------------------------------------------------------------------------------------------------------------------
String empId="rom01";
ObjectOutputStream output = new      ObjectOutputStream(servletConnection.getOutputStream());
output.writeObject(new String(empId));

--------------------------------------------------------------------------------------------------------------------------------------
The servlet gets the input:

                 //open InputStream
            ObjectInputStream input=new ObjectInputStream(req.getInputStream());
              String empId=(String)input.readObject();
-----------------------------------------------------------------------------------------------------------------------------------

//servlet doGet method opens OutputStream
    ObjectOutputStream output=new ObjectOutputStream(res.getOutputStream());


                  
// Set the contenty type to application/octet-stream
                  res.setContentType("application/octet-stream");
                       
            
Vector emp = new Vector();
emp.add(0,new String("he"));
emp.add(1,new String("she"));

output.writeObject(emp);

-----------------------------------------------------------------------------------------------------------------------------------------------


When I call the method which in turns communicates with the servlet I get this error message:

exception

java.io.EOFException
      java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2232)
      java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2698)
      ...

--------------------------------------------------------------------------------------------------------------------------------------------
also the application servers gives this exception message:

java.lang.NullPointerException
        at java.lang.String.<init>(String.java:144)
        at TableTest.doGet(TableTest.java:37)
        at TableTest.doPost(TableTest.java:66)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------


I have left out try and catch blocks in order not to clutter the message.

What do you think is the problem with this code ?

Thanks

Mimo


      
            

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Asked On
2006-01-27 at 16:16:31ID21713475
Tags

objectinputstream

Topic

Java Programming Language

Participating Experts
2
Points
200
Comments
8

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Answers

 

by: objectsPosted on 2006-01-27 at 23:13:26ID: 15811286

looks like the server is trying to create a string with null, so the connection is getting closed
can you post all the code for send/recieving on the stream at bvoth ends.

 

by: CEHJPosted on 2006-01-28 at 04:45:53ID: 15811920

Get rid of

>> res.setContentType("application/octet-stream");

>>
Vector emp = new Vector();
emp.add(0,new String("he"));
emp.add(1,new String("she"));
>>

can be

Vector emp = new Vector();
emp.add("he");
emp.add("she");

 

by: asaliuPosted on 2006-01-28 at 07:11:52ID: 15812360

Hello,

I tried the suggestion of CEHJ but I got the same Exception message.

Here is the full code as OBJECTS asked for:

public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException {
            //open InputStream
            ObjectInputStream input=new ObjectInputStream(req.getInputStream());
            // open OutputStream
            
                ObjectOutputStream output=new ObjectOutputStream(res.getOutputStream());
            
                try {
                  // read the employee id sent by the apple
                     String empId=(String)input.readObject();
                  
                        // Set the contenty type to application/octet-stream
                  res.setContentType("application/octet-stream");
                       
                  // getConnection method returns a
                  // connection to the Employee database
                  Connection con=getConnection();
                  Vector emp = new Vector();
                  if(con != null) {
                        
                               String[] empDetails = fetchDetails(con,empId.toString());
                               
                        emp.add(0, new String(empDetails[0]));
                        emp.add(1, new String(empDetails[1]));

                  } else {
                        // Connection was not successful, return proper messages
                        emp.add(0, new String("Could not establish"));
                        emp.add(0, new String("connection to database"));
                  }

                  // Close the connection
                  try {
                        con.close();
                  } catch(SQLException se) {
                            System.out.println("error 1");
                        se.printStackTrace();
                  }

                  // Send data
                  output.writeObject(emp);
            } catch(Exception e) {
                  System.out.println(e.getMessage());
                         System.out.println("error 2");
                  e.printStackTrace();
            }

            // flush the output and close
            output.flush();
            output.close();
      }



public void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException {
            doGet(req,res);
      }
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
I have avoided the use of ObjectInputStream input in order to make the scenario simplier.


 private void searchTest() {

            // get the employee id keyed in
            String empId="rom01";

            try {

                  // Initialize URL to call the servlet
                  URL url=new      URL("http://localhost:8084/TableTest");

                   // Open the connection to servlet.
                   URLConnection servletConnection = url.openConnection();
                  //System.out.println("Point 1");
                  // Set client caching to false
                  servletConnection.setUseCaches(false);

                  // Enable I/O through the connection
                  servletConnection.setDoInput(true);
                  servletConnection.setDoOutput(true);

                  // set request content type to object type
                  servletConnection.setRequestProperty("Content-Type", "application/octet-stream ");

                  // gets the InputStream on the servlet  and send employee
                  //id to the servlet
                  ObjectOutputStream output = new      ObjectOutputStream(servletConnection.getOutputStream());

                  // Pass the employee ID
                  output.writeObject(new String(empId));

                  // flush and close the output
                  output.flush();
                  output.close();

                  // get the InputStream from the servlet and read the
                  //Employee  object
                  InputStream input = servletConnection.getInputStream();
                  ObjectInputStream ois = new ObjectInputStream(input);

                  // Get the employee object
                  Vector emp=(Vector)ois.readObject();
                  ois.close();

                  // Get the details
                  String name=(String) emp.elementAt(0);
                  String city=(String) emp.elementAt(1);

                   // set the values read into the text boxes
                   jTableStyle.setValueAt(name,1,1);
                        jTableStyle.setValueAt(city,1,2);
                   
                   //System.out.println("Finished Applet...");
            } catch(Exception e) {
                  // Exception occured during search
                  e.printStackTrace();
                  // Display message in text boxes
                  board.setText("other Exception");
            }
      }

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
I do get error message no 2  at line
System.out.println("error 2");

Thanks

Mimo

 

by: CEHJPosted on 2006-01-28 at 07:18:52ID: 15812391

>>String empId=(String)input.readObject();

What value do you get for the above?

 

by: CEHJPosted on 2006-01-28 at 07:23:15ID: 15812411

Also, as i mentioned before, you can't set content types and stuff if you're using ObjectInput/Output. Any HTTP headers will make reading the streams fall over

 

by: asaliuPosted on 2006-01-28 at 09:24:59ID: 15812898

Thank you CEHJ,
it solved my problem

Mimo

 

by: CEHJPosted on 2006-01-28 at 09:26:50ID: 15812906

:-)

 

by: objectsPosted on 2006-01-28 at 16:10:04ID: 15815137

> you can't set content types and stuff if you're using ObjectInput/Output.

Thats incorrect, you can (and should) set them :)
You just need to set them before using the stream (as with any stream, not just OIS/OOS).

20120131-EE-VQP-002

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