Can't read Data input Stream in java IO

Question

Hi everyone i am practicing with java data input output stream. But i don't know how to fix this problem i can write data input stream to my file but can't read it

here is my code:

public static void readDataIOStream(){
            DataInputStream dataIn = null;

            int i = 10;
            double d = 1023.56;
            boolean b = true;

            try {
                dataIn = new DataInputStream(
                        new FileInputStream("test.txt"));

                i = dataIn.readInt();
                System.out.println("Reading " + i);
                d = dataIn.readDouble();
                System.out.println("Reading " + d);
                b = dataIn.readBoolean();
                System.out.println("Reading " + b);
                d = dataIn.readDouble();
                System.out.println("Reading " + d);
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }try {
                dataIn.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        public static void writeDataIOStream(){
            DataOutputStream dataOut = null;

            int i = 10;
            double d = 1023.56;
            boolean b = true;

            try {
                dataOut = new DataOutputStream(new FileOutputStream("test.txt"));
                System.out.println("Writing " + i);
                dataOut.write(i);
                System.out.println("Writing " + d);
                dataOut.writeDouble(d);
                System.out.println("Writing " + b);
                dataOut.writeBoolean(b);
                System.out.println("Writing " + 12.2 * 7.4);
                dataOut.writeDouble(12.2 * 7.4);
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                try {
                    dataOut.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

and here is error :

 java.io.EOFException
    at java.io.DataInputStream.readFully(Unknown Source)
    at java.io.DataInputStream.readLong(Unknown Source)
    at java.io.DataInputStream.readDouble(Unknown Source)
    at bytestream.DataIOStream.readDataIOStream(DataIOStream.java:108)
    at bytestream.DataIOStream.main(DataIOStream.java:16)
Writing 10
Writing 1023.56
Writing true
Writing 90.28
Reading 172003324
Reading 8.029891292620447E283
Reading true

Please help me why i can't read Data Input stream

Jean Logeart · Accepted Answer · 2014-10-18 13:45:53Z

2

dataOut.write(i) only writes one byte. Yet you are reading an int doing i = dataIn.readInt() which is 4 bytes.

Therefore when trying to read the last element which is a double, there is only 5 bytes in the stream while it is trying to read 8 bytes (the length of a double), hence the exception.

Since you want to write/read an int, you need to call dataOut.writeInt(i) instead of dataOut.write(i).

edited Oct 18, 2014 at 13:45

answered Oct 18, 2014 at 5:17

Jean Logeart

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1 Comment

Rustam Over a year ago

you are missing instead of dataOut.write(i);

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