如果找不到Java拆分中的字符串,该怎么办？

import java.util.regex.Pattern;

public class StringSplit {
    public static void main(String[] args) {
        String str = "Hello,World!";
        String[] splitStr = Pattern.compile(",").split(str);
        System.out.println(splitStr[0]); // 输出：Hello
        System.out.println(splitStr[1]); // 输出：World!
    }
}

public class StringSplit {
    public static void main(String[] args) {
        String str = "Hello,World!";
        String[] splitStr = str.split(",");
        System.out.println(splitStr[0]); // 输出：Hello
        System.out.println(splitStr[1]); // 输出：World!
    }
}

import java.util.StringTokenizer;

public class StringSplit {
    public static void main(String[] args) {
        String str = "Hello,World!";
        StringTokenizer tokenizer = new StringTokenizer(str, ",");
        while (tokenizer.hasMoreTokens()) {
            System.out.println(tokenizer.nextToken()); // 输出：Hello, World!
        }
    }
}

import java.util.Scanner;

public class StringSplit {
    public static void main(String[] args) {
        String str = "Hello,World!";
        Scanner scanner = new Scanner(str).useDelimiter(",");
        while (scanner.hasNext()) {
            System.out.println(scanner.next()); // 输出：Hello, World!
        }
    }
}