Java allows the user to input two dates, use a program to determine the relationship between the two dates, and output the number of days between the two dates.

1. Question

Write a java program
where the user inputs two dates and uses the program to determine the relationship between the two dates and the number of days between the two dates.

2. Code content

package com.hzcollege.Demo;

import java.util.Calendar;
import java.util.Scanner;

/**
 * 日期测试类
 * 用户输入两个日期，用程序判断两个日期的大小关系，以及两个日期之间的间隔天数。
 *
 * @author hhh
 * @version 1.8.0
 */
public class DemoDate {
    
    
    public static void main(String[] args) {
    
    
        //创建Scanner类实例
        Scanner sc = new Scanner(System.in);
        //获取当前时间
        Calendar calendar1 = Calendar.getInstance();
        //第一个日期输入
        System.out.println("第一个日期");
        System.out.print("请输入年：");
        int y1 = sc.nextInt();

        System.out.print("请输入月：");
        int m1 = sc.nextInt();

        System.out.print("请输入日：");
        int d1 = sc.nextInt();

        System.out.println("日期为：" + y1 + "年" + m1 + "月" + d1 + "日");
        //把用户录入的时间传入到calendar1中
        calendar1.set(y1, m1, d1);

        //第二个日期的输入
        Calendar calendar2 = Calendar.getInstance();
        System.out.println("第二个日期");
        System.out.print("请输入年：");
        int y2 = sc.nextInt();

        System.out.print("请输入月：");
        int m2 = sc.nextInt();
        //将int型数值转换为字符串
        String m = String.valueOf(m2);

        System.out.print("请输入日：");
        int d2 = sc.nextInt();

        System.out.println("日期为：" + y2 + "年" + m2 + "月" + d2 + "日");
        //把用户录入的时间传入到calendar2中
        calendar2.set(y2, m2, d2);

        //将日期转换为以毫秒为单位的时间
        long t1 = calendar1.getTimeInMillis();
        long t2 = calendar2.getTimeInMillis();
        //判断两个日期的大小
        if(t1>t2)
            System.out.println("第一个日期大");
        else
            System.out.println("第二个日期大");

        //计算两个日期之间的间隔
        long day = Math.abs(t1 - t2) / (24 * 60 * 60 * 1000);
        System.out.println(y1 + "年" + m1 + "月" + d1 + "日" + "与" + y2 + "年" + m + "月" + d2 + "日" + "相隔" + day + "天");
    }
}

3. Operation results

4. Summary

Through this program, I learned to use the abs() method in the Math class, the valueOf() method in the String class
, and learned to use the methods in the Calendar class to process dates.