How to write binary data into files in Java?

Question

Is there a way to store some values in a binary file as C# does?

For example in C# it would be:

BinaryWriter bw = new BinaryWriter(MyFilStream);
bw.Write(data...);

And then, to read it like

BinaryReader br = new bla bla...;
br.ReadInt(file);

Is there a way to do this in Java? I'm Reading a lot of binary reading in Google, but I just find something of a JPG file, don't get it...

Check Serializable, ObjectInputStream and ObjectOutputStream. — Luiggi Mendoza
– Luiggi Mendoza, Commented Aug 12, 2014 at 19:11
Yes, you can write (and read) binary data. I suggest you look at DataOutputStream. — Elliott Frisch
– Elliott Frisch, Commented Aug 12, 2014 at 19:14

Unihedron · Accepted Answer · 2014-08-13 04:54:13Z

4

You could make use of DataOutputStream and/or DataInputStream to store and read binary data in Java.

Here is an example of how it's done:

import java.io.*;

public class Test{
    public static void main(String args[])throws IOException{

        DataInputStream d = new DataInputStream(new 
                                 FileInputStream("test.txt"));

        DataOutputStream out = new DataOutputStream(new 
                                 FileOutputStream("test1.txt"));

        String count;
        while((count = d.readLine()) != null){
            String u = count.toUpperCase();
            System.out.println(u);
            out.writeBytes(u + "  ,");
        }
        d.close();
        out.close();
    }
}

Editors' note:

.close() statements should be wrapped in finally block:
finally {
    d.close();
    out.close();
}

Source:
http://www.tutorialspoint.com/java/java_dataoutputstream.htm

edited Aug 13, 2014 at 4:54

Unihedron

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answered Aug 12, 2014 at 19:17

ihsan

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1 Comment

bruno Over a year ago

You should make sure you close your streams in a finally block.

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