java 方法compareTo 的比较方法

Question

import java.util.Scanner;

public class CheackASNN {
public static void main(String[] args){
String str = new String();
Scanner input = new Scanner(System.in);
System.out.print("Enter a SSN :");
str = input.next();
System.out.println();

// if(str.substring(3, 4) == "-" && str.substring(6, 7) == "-"){
// System.out.println(str+"is a valid SSN");
// }
String lowBound = "000-00-0000";
String topBound = "999-99-9999";

    if(str.compareTo(lowBound) >=0  &&  str.compareTo(topBound)<=0 && str.length()==11){
        System.out.println(str+" is a valid SSN");
    }
    else{
        System.out.println(str+" is a invalid SSN");
    }
}

}

//请问这串代码中，字符串str 不在000-00-0000到999-99-9999之间吗？
//发现输入12345678912，也显示正确

Answer 1

java比较字符串用equals不用==