java - 用 "*"替换最后 4 个字符

Question

我有一个字符串，我需要用“*”符号替换字符串的最后 4 个字符。谁能告诉我怎么做。

Answer 1

一种快速简便的方法...

public static String replaceLastFour(String s) {
    int length = s.length();
    //Check whether or not the string contains at least four characters; if not, this method is useless
    if (length < 4) return "Error: The provided string is not greater than four characters long.";
    return s.substring(0, length - 4) + "****";
}

现在您所要做的就是使用字符串作为参数调用replaceLastFour(String s)，如下所示:

public class Test {
    public static void main(String[] args) {
        replaceLastFour("hi");
        //"Error: The provided string is not greater than four characters long."
        replaceLastFour("Welcome to StackOverflow!");
        //"Welcome to StackOverf****"
    }

    public static String replaceLastFour(String s) {
        int length = s.length();
        if (length < 4) return "Error: The provided string is not greater than four characters long.";
        return s.substring(0, length - 4) + "****";
    }
}