Date d1 = xxx
Date d2 = xxx
d1_D2_jueduizhi = (d1.getTime() - d2.getTime())/(24*3600*1000);
d1_D2_tianshucha = d1.getTime()/(24*3600*1000) - d2.getTime()/(24*3600*1000);that's ok
先除后减和先减后除是有区别的,看你的需要了。
Date d2 = xxx
d1_D2_jueduizhi = (d1.getTime() - d2.getTime())/(24*3600*1000);
d1_D2_tianshucha = d1.getTime()/(24*3600*1000) - d2.getTime()/(24*3600*1000);that's ok
先除后减和先减后除是有区别的,看你的需要了。
import java.util.*;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;public class DateDiff{
public static void main(String[] args){
String s1= "20040301";
String s2="20040330";
DateFormat df1 = new SimpleDateFormat("yyyyMMDD");
Date date1=new Date();
Date date2=new Date();
String strResult="";
Calendar d1=Calendar.getInstance();
Calendar d2=Calendar.getInstance(); try{
date1= df1.parse(s1) ;
date2= df1.parse(s2) ;
d1.setTime(date1);
d2.setTime(date2);
long result;
result=dateDiff("DAY",d1,d2);
strResult=String.valueOf(result);
}catch(ParseException e){ }
System.out.println(strResult);
}
public static long dateDiff(String part, Calendar startCal, Calendar endCal) {
long deltaMs = endCal.getTimeInMillis() - startCal.getTimeInMillis(); if ("MILLISECOND".equalsIgnoreCase(part)) {
return deltaMs;
} int reverse = 1;
//if start time is after the end time
if(startCal.after(endCal)){
reverse = -1;
deltaMs = -deltaMs;
Calendar tmp = startCal;
startCal = endCal;
endCal = tmp;
} long res = 0; if ("YEAR".equalsIgnoreCase(part)) {
res = endCal.get(Calendar.YEAR) - startCal.get(Calendar.YEAR);
} else if ("MONTH".equalsIgnoreCase(part)) {
int year = endCal.get(Calendar.YEAR) - startCal.get(Calendar.YEAR);
res += year * 12;
res += endCal.get(Calendar.MONTH) - startCal.get(Calendar.MONTH);
} else if ("WEEK".equalsIgnoreCase(part)) {
res += deltaMs / (7 * 24 * 3600 * 1000);
int w = startCal.get(Calendar.DAY_OF_WEEK);
int tmp = (int)(deltaMs % (7*24*3600*1000));
startCal.add(Calendar.MILLISECOND,tmp);
int w2 = startCal.get(Calendar.DAY_OF_WEEK);
if(w2<w || (w2 == w && tmp>(24*3600*1000))){
res++;
}
} else{
long base = 0;
int type = 0;
if ("DAY".equalsIgnoreCase(part)) {
type = Calendar.DATE;
base = 24 * 3600 * 1000;
} else if ("HOUR".equalsIgnoreCase(part)) {
type = Calendar.HOUR;
base = 3600 * 1000;
} else if ("MINUTE".equalsIgnoreCase(part)) {
type = Calendar.MINUTE;
base = 60 * 1000;
} else if ("SECOND".equalsIgnoreCase(part)) {
type = Calendar.SECOND;
base = 1000;
}else{
return Long.MIN_VALUE;
}
int cur = startCal.get(type);
res = deltaMs / base;
int tmp = (int)(deltaMs % base);
startCal.add(Calendar.MILLISECOND,tmp);
if(startCal.get(type)!=cur){
res++;
}
} return res*reverse;
}}