How to convert Decimal to Binary ?

Hi all,

I'm trying to convert a string into Binary numbers, grouped by 6bits. Then, I must drop the ending 0's to get groups of 8bits and reconverts each group into characters that will form a decoded string.

ex.

I have an encoded string : "PVql[p"
I need to convert it into binary, grouped in 6bits groups: "010000 010110 110001 101100 011011 110000"
Then convert again the binary string into 8bits groups (dropping the last 0s): "01000001 01101100 01101100 01101111"
Finaly, convert the binary groups into characters: A  L  L  O

*** Problem #1
My main problem is that I was using the Integer class function "toBinaryString" which don't returns the leading 0 if the number has some. (00100101 = 100101)

Here's what I was doing (note. I didnt used function because I was just testing quickly...):

// Each encoded caracter of the string is converted to a decimal value
// which is also converted into binary of base 6.

for (int i = 0; i <= theString.length(); i++)
{
   // Convert the current char into Decimal
   decimalValue = theString.charAt(i);

   // Convert the current Decimal into Binary (*** See Problem #1 - The rest won't work correctly...)
   binaryValue = Integer.toBinaryString(decimalValue);

   // Building the binary string with all the converted characters
   binaryString += binaryValue
 }

// Printing the converted string         
System.out.println("The binary string is: " + binaryString);

// We need to format the binary string into 8bits groups
for( int i = 0, k = 0; i <= binaryString.length() - 1; i++, k++)
{
   // We create a group
   if(k == 8)
   {
      k = 0;
      decimalVal = Integer.parseInt(binaryString.substring(i - 8, i), 2);

      decimalString += (char) (decimalVal);
   }
}
System.out.println("The decimal string is: " + decimalString);



Thanks a lot for the help,

Frank