package com.zrp.apartday;
/**
* 这个类主要的功能是计算任意两个日期的相隔天数，主要算法思想是
* 1.计算开始日期到该年结束日期的相隔天数 如：开始日期为：2009-07-12 则求出到该日期到 2009-12-31日的相隔天数
* 2.计算结束日期到改年开始日期的相隔天数 如：结束日期为: 2025-08-05 则求出该日期到 2025-01-01
* 3.计算出2010年到2024年的所有的天数
* 4.把以上所有的天数相加
* @author Administrator
*
*/
public class DateApartDays {
/**
* This is constructed function
*/
public DateApartDays(){};
/**
* 比较两个日期大小,写成静态方法
* @param startDate,endDate
* @return boolean
*/
public boolean DateCompare(String startDate,String endDate){
boolean begBinggerEnd = Integer.valueOf(startDate)<=Integer.valueOf(endDate);
try
{
assert begBinggerEnd:"开始日期必须要大于结束日期!";
}catch(AssertionError err)
{
System.out.println(err.getMessage());
}
return !begBinggerEnd;
}
/**
* 计算两个日期相隔的天数
* @param startDate, endDate
* @return The apart days
*/
public int SumDays(String startDate,String endDate ){
int sumDays=0;
int tempBeginYear = getYear(startDate);
int tempEndYear = getYear(endDate);
if(DateCompare(startDate,endDate))
{
return -1;
}
else if(tempBeginYear==tempEndYear)
{
sumDays = pastDays(endDate)-pastDays(startDate);
}
else
{
for(int i = getYear(startDate)+1;i<getYear(endDate);i++)
{
if(IsLeapYearFromYear(i))
sumDays+=366;
else
sumDays+=365;
}
sumDays+=SurplusDay(startDate);
sumDays+=pastDays(endDate);
}
return sumDays;
}
/**
* 从日期中获取年
* @param date
* @return year
*/
private int getYear(String date)
{
return Integer.valueOf(date)/10000;
}
/**
* 从日期中获取月
* @param date
* @return month
*/
private Integer getMonth(String date)
{
return Integer.valueOf(date)%10000/100;
}
/**
* 从日期中获取日
* @param date
* @return days
*/
private Integer getDay(String date){
return Integer.valueOf(date)%10000%100;
}
/**
* 判断某个日期是否是闰年
* @param Date
* @return boolean
*/
private boolean isLeapYear(String Date){
if((getYear(Date)%4==0&&getYear(Date)%100!=0)||getYear(Date)%400==0){
return true;
}
else{
return false;
}
}
/**
* 判断某年是否是闰年
* @param Date
* @return boolean
*/
private boolean IsLeapYearFromYear(int year){
if((year%4==0&&year%100!=0)||year%400==0){
return true;
}
else{
return false;
}
}
/**
* 计算某日期到该年开始的相隔天数
* @param Date
* @return 相隔天数
*/
private int pastDays(String Date){
int tempSumDays=0;
if(isLeapYear(Date)){
for(int i=1;i<getMonth(Date);i++){
switch(i){
case 1:
tempSumDays+=31;
break;
case 2:
tempSumDays+=29;
break;
case 3:
tempSumDays+=31;
break;
case 4:
tempSumDays+=30;
break;
case 5:
tempSumDays+=31;
break;
case 6:
tempSumDays+=30;
break;
case 7:
tempSumDays+=31;
break;
case 8:
tempSumDays+=31;
break;
case 9:
tempSumDays+=30;
break;
case 10:
tempSumDays+=31;
break;
case 11:
tempSumDays+=30;
break;
}
}
tempSumDays += getDay(Date);
return tempSumDays;
}
else{
for(int i=1;i<getMonth(Date);i++){
switch(i){
case 1:
tempSumDays+=31;
break;
case 2:
tempSumDays+=28;
break;
case 3:
tempSumDays+=31;
break;
case 4:
tempSumDays+=30;
break;
case 5:
tempSumDays+=31;
break;
case 6:
tempSumDays+=30;
break;
case 7:
tempSumDays+=31;
break;
case 8:
tempSumDays+=31;
break;
case 9:
tempSumDays+=30;
break;
case 10:
tempSumDays+=31;
break;
case 11:
tempSumDays+=30;
break;
}
}
tempSumDays += getDay(Date);
return tempSumDays;
}
}
/**
* 计算某日期到该年的结束的相隔天数
* @param Date
* @return 相隔天数
*/
private int SurplusDay(String Date){
if(isLeapYear(Date)){
return 366-pastDays(Date);
}
else{
return 365-pastDays(Date);
}
}
}