正则表达式Java问题代码不起作用

Question

I have an issue with a little regex code I wrote. The code basically checks my "longString" which contains the string that's being checked and outputs the words in the string that matches the regex.

import java.util.regex.*;

public class regexPractice 
{

    public static void main(String[] args) {
        String  longString = " Derek Banas CA ";

        regexChecker(longString, "\\s[A-Za-z]{2,20}\\s");
    }

    public static void regexChecker(String theregex, String stringCheck) {
        //theregex is the regex your searching for

        Pattern Checkregex = Pattern.compile(theregex);

        Matcher regexMatcher = Checkregex.matcher(stringCheck);

        while (regexMatcher.find()) { //kicks out all the matches for you
            if (regexMatcher.group().length() != 0) {
                System.out.println(regexMatcher.group().trim());
                //trim gets rid of all the white space
            }
        }
    }
}

When I run the code nothing shows up not even an error message. I rechecked my code and didn't find any errors.

By the way, I'm using android studio.

Answer 1

You are passing in your arguments in the wrong order. The method signature has them reversed

Answer 2

您的正则表达式不正确，因为您使用的aZ应该为“ z”（正常情况）。