I would like to convert a hex string to a binary string. For example, Hex 2 is 0010. Below is the code:
String HexToBinary(String Hex)
{
int i = Integer.parseInt(Hex);
String Bin = Integer.toBinaryString(i);
return Bin;
}
However this only works for Hex 0 - 9; it won't work for Hex A - F because it uses int. Can anyone enhance it?
You need to tell Java that the int is in hex, like this:
String hexToBinary(String hex) {
int i = Integer.parseInt(hex, 16);
String bin = Integer.toBinaryString(i);
return bin;
}
the accepted version will only work for 32 bit numbers.
Here's a version that works for arbitrarily long hex strings:
public static String hexToBinary(String hex) {
return new BigInteger(hex, 16).toString(2);
}
The accepted answer only works for 32-bit values, and the alternate BigInteger version truncates leading zeros in the binary string! Here's a function that should work in all cases.
public static String hexToBinary(String hex) {
int len = hex.length() * 4;
String bin = new BigInteger(hex, 16).toString(2);
//left pad the string result with 0s if converting to BigInteger removes them.
if(bin.length() < len){
int diff = len - bin.length();
String pad = "";
for(int i = 0; i < diff; ++i){
pad = pad.concat("0");
}
bin = pad.concat(bin);
}
return bin;
}
Here are some routines I wrote for manipulating hex, plaintext, and binary, hope they help. Since I borrowed ideas from these threads, thought I would share.
public static String zero_pad_bin_char(String bin_char){
int len = bin_char.length();
if(len == 8) return bin_char;
String zero_pad = "0";
for(int i=1;i<8-len;i++) zero_pad = zero_pad + "0";
return zero_pad + bin_char;
}
public static String plaintext_to_binary(String pt){
return hex_to_binary(plaintext_to_hex(pt));
}
public static String binary_to_plaintext(String bin){
return hex_to_plaintext(binary_to_hex(bin));
}
public static String plaintext_to_hex(String pt) {
String hex = "";
for(int i=0;i<pt.length();i++){
String hex_char = Integer.toHexString(pt.charAt(i));
if(i==0) hex = hex_char;
else hex = hex + hex_char;
}
return hex;
}
public static String binary_to_hex(String binary) {
String hex = "";
String hex_char;
int len = binary.length()/8;
for(int i=0;i<len;i++){
String bin_char = binary.substring(8*i,8*i+8);
int conv_int = Integer.parseInt(bin_char,2);
hex_char = Integer.toHexString(conv_int);
if(i==0) hex = hex_char;
else hex = hex+hex_char;
}
return hex;
}
public static String hex_to_binary(String hex) {
String hex_char,bin_char,binary;
binary = "";
int len = hex.length()/2;
for(int i=0;i<len;i++){
hex_char = hex.substring(2*i,2*i+2);
int conv_int = Integer.parseInt(hex_char,16);
bin_char = Integer.toBinaryString(conv_int);
bin_char = zero_pad_bin_char(bin_char);
if(i==0) binary = bin_char;
else binary = binary+bin_char;
//out.printf("%s %s\n", hex_char,bin_char);
}
return binary;
}
public static String hex_to_plaintext(String hex) {
String hex_char;
StringBuilder plaintext = new StringBuilder();
char pt_char;
int len = hex.length()/2;
for(int i=0;i<len;i++){
hex_char = hex.substring(2*i,2*i+2);
pt_char = (char)Integer.parseInt(hex_char,16);
plaintext.append(pt_char);
//out.printf("%s %s\n", hex_char,bin_char);
}
return plaintext.toString();
}
}
You need to use the other Integer.parseInt() method.
Integer.parseInt(hex, 16);
private static Map<String, String> digiMap = new HashMap<>();
static {
digiMap.put("0", "0000");
digiMap.put("1", "0001");
digiMap.put("2", "0010");
digiMap.put("3", "0011");
digiMap.put("4", "0100");
digiMap.put("5", "0101");
digiMap.put("6", "0110");
digiMap.put("7", "0111");
digiMap.put("8", "1000");
digiMap.put("9", "1001");
digiMap.put("A", "1010");
digiMap.put("B", "1011");
digiMap.put("C", "1100");
digiMap.put("D", "1101");
digiMap.put("E", "1110");
digiMap.put("F", "1111");
}
static String hexToBin(String s) {
char[] hex = s.toCharArray();
String binaryString = "";
for (char h : hex) {
binaryString = binaryString + digiMap.get(String.valueOf(h));
}
return binaryString;
}
Sorry, it's been a little bit late. But still, I think my answer is the most straight forward and simple one.
public static String hexToBits(String s) {
if (s == null || s.length()==0) return "";
String ret = new BigInteger(s, 16).toString(2);
int totalLength = s.length() * 4;
while (totalLength - ret.length() > 0) {
ret = "0" + ret;
}
return ret;
}
repeat method (replacement for the while loop, since Java 11)