java string 删除第一个字符

public class Main {
    public static void main(String[] args) {
        String str = "Hello World";
        if (str != null && !str.isEmpty()) {
            str = str.substring(1);
        }
        System.out.println(str); // 输出 "ello World"
    }
}

public class Main {
    public static void main(String[] args) {
        String str = "Hello World";
        StringBuilder sb = new StringBuilder(str);
        if (sb.length() > 0) {
            sb.deleteCharAt(0);
        }
        System.out.println(sb.toString()); // 输出 "ello World"
    }
}

public class Main {
    public static void main(String[] args) {
        String str = "Hello World";
        str = str.replaceAll("^.", "");
        System.out.println(str); // 输出 "ello World"
    }
}