java - How to convert 160 digit binary string to 20 byte array? -

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• in java, how convert byte array string of hex digits while keeping leading zeros? 27 answers

i have binary string containing 160 digit. have tried:

new biginteger("0000000000000000000000000000000000000000000000010000000000000000000000000000001000000000010000011010000000000000000000000000000000000000000000000000000000000000", 2).tobytearray() 

but returns 15 bytes array removed leading 0 bytes.

i reserve leading 0 bytes, keep 20 bytes.

i know other ways accomplish that, know there easier way might need few lines of code.

why not simply:

public static byte[] convert160bitstobytes(string binstr) {     byte[] = new biginteger(binstr, 2).tobytearray();     byte[] b = new byte[20];     int = 20 - a.length;     int j = 0;     if (i < 0) throw new illegalargumentexception("string long");     (; j < a.length; j++,i++) {         b[i] = a[j];     }     return b; }