casting from String to byte[]

I have a string

String gString="00000000";
and i want to convert this to an array of byte[]

that is


byte[] result should equal{0,0,0,0,0,0,0,0}. please how do i do this

If you check the API, you will see that String already has a method that will return an array of bytes.

However, a String is made up of chars, and the char '0' does not have a numeric (byte) value of zero, so you will need to adjust for this. See ASCIITable.com.

But your String does not equal {0,0,0,0,etc}. It equals {30, 30, 30 etc} in hexadecimal.
You would have to parse each individual character in an array and cast it to a byte and insert the value in a new array.

Note: In Java, a String is not simply an array of chars, so you cannot "cast" a String to an array. (See JLS - 10.9 An Array of Characters is Not a String.)

Well, you certainly can't do this by casting, because a String is now an array of bytes. But it's possible to write a method that will take a String "00000000" as input, and return a byte[] containing { 0, 0, 0, 0, 0, 0, 0, 0 } as output - if that's really what you want. A rough algorithm:
create a byte[] with the same length as the length of the String for each character in the String { convert the character to a single byte, such that '0' becomes 0 set the corresponding element in the byte[] array to that number } return the byte[] array
Is that what you're trying to do?
[ October 19, 2007: Message edited by: Jim Yingst ]

Yes jim thats what i want

Originally posted by Jim Yingst:
Well, you certainly can't do this by casting, because a String is now an array of bytes. But it's possible to write a method that will take a String "00000000" as input, and return a byte[] containing { 0, 0, 0, 0, 0, 0, 0, 0 } as output - if that's really what you want. A rough algorithm:
create a byte[] with the same length as the length of the String for each character in the String { convert the character to a single byte, such that '0' becomes 0 set the corresponding element in the byte[] array to that number } return the byte[] array
Is that what you're trying to do?

[ October 19, 2007: Message edited by: Jim Yingst ]

Yes jim thats what i want

Well, Jim did a good job writing the pseudo code for you. It should be easy for you to convert that to Java.

Henry

You can use the getBytes() method of String class also ...and then cast each byte of the array to char for further use....here is the code below...

class StringByte
{
public static void main(String[] args)
{
String str = "00000000";
byte[] b = str.getBytes();

System.out.println("Hello World!-----"+b.length);

for(int i = 0; i < b.length; i++)
System.out.println("element ----"+(char)b[i]);
}
}