问题:

How do I remove white-space from the beginning of a string in Java without removing from the end?

If the value is:

String temp = "    hi    "

Then how can I delete only the leading white-space so it looks like this:

String temp = "hi    "

The current implementation I have is to loop through, checking the first character and creating a substring until the first non-whitespace value is reached.

Thanks!

回答1:

You could use:

temp = temp.replaceFirst("^\\s*", "")

回答2:

You could use Commons-lang StringUtils stripStart method.

If you pass null it will automatically trim the spaces.

StringUtils.stripStart(temp, null);

回答3:

Probably close to the implementation of the suggested Commons-lang StringUtils.stripStart() method:

public static String trimFront(String input) {
    if (input == null) return input;
    for (int i = 0; i < input.length(); i++) {
        if (!Character.isWhitespace(input.charAt(i)))
            return input.substring(i);
    }
    return "";
}