Java 实现分时问候

import java.util.*;

public class lianxi {
    public static void main(String[] args){

        Calendar c = Calendar.getInstance();
        int a = c.get(Calendar.HOUR_OF_DAY);
        if(a<9&&a>=6){
            System.out.println("早上好！");
        }
        else if (a<12&&a>=9){
            System.out.println("中午好！");
        }
        else if (a<18&&a>=12){
            System.out.println("下午好！");
        }
        else if (a>=18&&a<24){
            System.out.println("晚上好！");
        }

    }
}