字符串比较

public class StringDemo {
    public static void main(String[] args) {
        String str = "hello";
        System.out.println("Hello".equals(str));  //区分大小写比较
        System.out.println("Hello".equalsIgnoreCase(str));  //不区分大小写比较
    }
}

false
true

public class StringDemo {
    public static void main(String[] args) {
        System.out.println("A".compareTo("a"));
        System.out.println("a".compareTo("A"));
        System.out.println("a".compareTo("a"));
        System.out.println("ab".compareTo("ac"));
        System.out.println("范".compareTo("周")); //没有意义
    }
}

-32
32
0
-1
11931