write raw binary to file java

Question

Say I have a binary string ("0 and 1s") and I want to write this string to a binary file, how can this be done in java? I tried converting to ASCII values string, then create a ByteArrayInputStream from that but values over 127 do not display correctly. Can anyone help me with this? My binaryToAscii method:

public static String BinaryToAscii(String bin){
    int num_of_bytes = bin.length()/8;
    StringBuilder sb = new StringBuilder();
    int index = 0;
    String byte_code;
    Character char_code;
    for (int i =0; i<num_of_bytes;i++){
        index = i*8;
        byte_code = bin.substring(index,index+8);
        int charCode = Integer.parseInt(byte_code, 2);
        char_code = new Character((char)charCode);
        sb.append(char_code);
    }
    return sb.toString();
}

Then I convert the returned string to a ByteArrayInputStream using

InputStream is = new ByteArrayInputStream(ascii.toString().getBytes());

Instead of thank you notes please show example of what you have as input and what you want as output. Also showing code you've tried would make positive impression... — Alexei Levenkov
– Alexei Levenkov, Commented Jan 15, 2013 at 2:12
your method should not return String, it should return a byte[] — AlexWien
– AlexWien, Commented Jan 15, 2013 at 2:34

AlexWien · Accepted Answer · 2013-01-15 02:13:11Z

1

you first would transform the 0 / 1 string to a byte[].

then write out using

DataOutputStream.writeByte().

read in with
DataInputStream.readUnsignedByte() // to get 0 - 255

answered Jan 15, 2013 at 2:13

AlexWien

28.9k6 gold badges56 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

user1538814 Over a year ago

How would I convert the string to a byte[]? Is values that is over 127 going to cause problems?

Adrián Over a year ago

String : getBytes()

AlexWien Over a year ago

no not getBytes, you dont want to have a String to byte[] conversion. you want a 0/1 string to byte representarion conversion

AlexWien Over a year ago

instead od Stringbuilder add the int read in line Integer.parseInt to an int ( or byte) array.

user1538814 Over a year ago

What method do you use to convert an integer to byte[] and keep the binary representation?

|

java · Accepted Answer · 2013-01-15 02:55:22Z

1

To convert string to binary use this: You will first need to break the string into its individual letters then run them through this one at a time.

char letter = c;
  byte[] bytes = letter.getBytes();
  StringBuilder binary = new StringBuilder();
  for (byte b : bytes)
  {
     int val = b;
     for (int i = 0; i < 8; i++)
     {
        binary.append((val & 128) == 0 ? 0 : 1);
        val <<= 1;
     }
     binary.append(' ');
  }
  System.out.println(binary);

answered Jan 15, 2013 at 2:55

java

1,3496 gold badges15 silver badges31 bronze badges

1 Comment

user1538814 Over a year ago

i'm not sure where to go with this

Collectives™ on Stack Overflow

write raw binary to file java

2 Answers 2

9 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

9 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related