附加数据中的java.io.StreamCorruptedException

Question

I have written this java code for appending data in ObjectOutputStream, but this code is throwing (java.io.StreamCorruptedException:). Please help if this code can not work properly then please give an alternative for appending data in ObjectOutputStream.

import java.awt.Toolkit;
import java.io.EOFException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Vector;
import javax.swing.JOptionPane;


class Data implements Serializable {

    private static final long serialVersionUID = 1L;
    private String time;
    private String note;

    public Data(String time, String note) {
        this.time=time;
        this.note=note;
    }

    public String getTime() {
        return time;
    }

    public String getNote() {
        return note;
    }
}


public class S extends ObjectOutputStream {

    String t, n;

    public S(FileOutputStream w, String time, String note) throws Exception {
        super(w);
        t=time;
        n=note;
        writeStreamHeader();
    }

    protected void writeStreamHeader() throws IOException {
        writeObject(new Data(t,n));
        reset();
     }


    public static void rd() {

        Vector v = new Vector();
        Data d;

        try
        {
            ObjectInputStream r = new ObjectInputStream(new FileInputStream("file.cer"));

            for(int i=1; i<=100; i++) {
                try { v.add(r.readObject()); }
                catch(EOFException exp){
                    r.close();
                    break;
                }
            }
            for(int i=0; i<v.size(); i++) {
                d = (Data)v.elementAt(i);
                System.out.println(d.getNote()+" "+d.getTime());
            }
        }

        catch(Exception exp) {
            Toolkit.getDefaultToolkit().beep();
            JOptionPane.showMessageDialog(null, String.format("ERROR = %s\nCLASS = S", exp.getClass()));
            System.out.println(exp.getClass());
            System.exit(0);
        }
    }

    public static void main(String arg[]) throws Exception {
        FileOutputStream w  = new FileOutputStream("file.cer",true);
        new S(w,"99:59:59:99","Maxima"); 
        new S(w,"00:00:00:00","Minima"); 
        rd();
    }
}

Answer 1

if this code can not work properly

You are correct. It can not work properly.

then please give an alternative for appending data in ObjectOutputStream.

writeStreamHeader() must do nothing if the file is being appended to, but it must call super.writeStreamHeader() if the file is newly created. It certainly should not call writeObject() at any time.