Question

请高手帮忙编写一个java程序，不胜感激！

8. 设int year,month,day分别表示一个日期中的年月日，试编程求
a) 对于任意三个整数，判断其是否为一个合法的日期值。
b) 给定一个日期值，计算若干天后的日期值
c) 如果有两个日期值，计算他们相距的天数。

请高手不吝赐教，帮帮我这个菜鸟...

Answer 1

import java.util.Calendar;

public class Date {
private int year;
private int month;
private int day;

public Date(int year, int month, int date){
this.year = year;
this.month = month;
this.day = date;
}

public static void main(String[] args){
boolean isValid = Date.isValidatDate(2011, 2, 29);
System.out.println("20110229 is " + (isValid?"": "not") + " a date");

Date dt = new Date(2011, 2, 28);
String nextDay = dt.getNextDate(30);
System.out.println("After 30 days of 20110228, the date is: " + nextDay);

Date dt2 = new Date(2010, 2,27);

long julianDays = Date.getJulianDay(dt, dt2);
System.out.println("Days between 20100227 and 20110228 is: " + julianDays);

}

//检查日期方法
public static boolean isValidatDate(int y, int m, int d){
//如果年月日小于0，或者月份大于12，或者日期大于31，都为false
if(m > 12 || d > 31 || y <= 0 || m < 0 || d <= 0){
return false;
}

Calendar cal = Calendar.getInstance();

cal.set(Calendar.YEAR, y);
cal.set(Calendar.MONTH, m-1);

int maxDayOfMonth = cal.getActualMaximum(Calendar.DAY_OF_MONTH);

return d <= maxDayOfMonth;
}

//获得days后的日期
public String getNextDate(int days){
Calendar cal = Calendar.getInstance();
cal.set(year, month-1, day);

cal.add(Calendar.DATE, days);

int nextYear = cal.get(Calendar.YEAR);
int nextMonth = cal.get(Calendar.MONTH);
int nextDay = cal.get(Calendar.DATE);

return nextYear +"/" + (nextMonth + 1) + "/" +nextDay;
}

//求取两个日期之间相差得天数
public static long getJulianDay(Date dt1, Date dt2){

java.util.Date date1 = new java.util.Date(dt1.year, dt1.month-1, dt1.day-1);
java.util.Date date2 = new java.util.Date(dt2.year, dt2.month-1, dt2.day-1);

long millionSecondsDiffer = Math.abs(date1.getTime() - date2.getTime());

return millionSecondsDiffer / (1000*24*60*60);
}

}
------------------
20110229 is not a date
After 30 days of 20110228, the date is: 2011/3/30
Days between 20100227 and 20110228 is: 366

Answer 2

你直接用函数处理啊