如何在java中替换每个字符

Question

I have this task to mask the contents of a .CSV file using Java. Done with masking other field but the problem is masking the data in the Primary Key column. I tried using the code below but it doesn't work. How should I do it?

String str = src.replaceAll("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "QLBNAVHTROFSEJMIKWPYGDUCZX");

Answer 1

There are a number of ways you could do this, but regular expressions are not the approach I would choose. I would build a map of character to character and then iterate the characters in a given string building the transposed output with the map (and don't forget digits and lowercase letters). Something like,

private static Map<Character, Character> MASK_MAP = new HashMap<>();
static {
    String inChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 
          outChars = "QLBNAVHTROFSEJMIKWPYGDUCZX";
    inChars += inChars.toLowerCase()   + "0123456789";
    outChars += outChars.toLowerCase() + "8652103749";
    for (int i = 0; i < inChars.length(); i++) {
        MASK_MAP.put(inChars.charAt(i), outChars.charAt(i));
    }
}
private static String maskKey(String s) {
    StringBuilder sb = new StringBuilder(s.length());
    for (int i = 0; i < s.length(); i++) {
        sb.append(MASK_MAP.get(s.charAt(i)));
    }
    return sb.toString();
}

And then call

String out = maskKey(inputString);