（JAVA）将十进制转换为二进制编码的十进制？

Question

For example, I would like to convert the int value 12 into a String output of BCD: 00 12 (0x00 0x12). If I have int value of 256 , it will be 02 56 (which is 0x02 0x56), or if I have a int value of 999 , it will be 09 99 (0x09 0x99), 9999 would be 99 99 (0x99 0x99).

Right now, my only solution is to create a String array of size 4, and calculate how many characters are there by converting the int value into String. If there are 2 characters, I will add 2 x 0 into the array first before adding the 2 characters, and then make them back into a single String variable.

Basically,

int value = 12;
String output = Integer.toString(value); 
// then count the number of characters in the String.
// 4 minus (whatever number of characters in the String, add zeros
// add the characters:
stringArray[0] = "0";
stringArray[1] = "0";
stringArray[2] = "1";
stringArray[3] = "2";
// then, concatenate them back

If there are 3 characters, I will add one 0 into the array first before adding 3 characters. I was wondering if there is any other way?

Answer 1

Is that what you are asking for?

public static String formatTheString(String string, int length) {
    return String.format("%"+length+"s", string).replace(' ', '0');
}

and pass the values like

formatTheString(Integer.toString(256),4);

Answer 2

You can use String.format to append leading 0 and use substring to split in to two part.

int value = 12;
String output = String.format("%04d",value);
System.out.println(output.substring(0,2)+" "+output.substring(2,4));

String.format("%04d",value) will append 0 s in the front if the length is less than 4.

If you do not want to use substring you can use String.split and String.join like below.

System.out.println(
        String.join(
                " ",
                Arrays.asList(
                        output.split("(?<=\\G.{2})")
                )
        )
);

output.split("(?<=\\\\G.{2})") will split the string in 2 characters each.

Answer 3

I think what you are asking is not correct. refer this for BCD.

and below code is sufficient for what you need

System.out.printf("%04d",n);

in above code n is your number.