1.计算天数差。
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String fromDate = simpleFormat.format("2016-05-01 12:00")
String toDate = simpleFormat.format("2016-06-01 12:00")
long from = simpleFormat.parse(fromDate).getTime()
long to = simpleFormat.parse(toDate).getTime()
int days = (int) ((to - from)/(1000 * 60 * 60 * 24))
2.计算小时差
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String fromDate = simpleFormat.format("2016-05-01 12:00")
String toDate = simpleFormat.format("2016-05-01 14:00")
long from = simpleFormat.parse(fromDate).getTime()
long to = simpleFormat.parse(toDate).getTime()
int hours = (int) ((to - from)/(1000 * 60 * 60))
3.计算分钟差：
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String fromDate = simpleFormat.format("2016-05-01 12:00")
String toDate = simpleFormat.format("2016-05-01 12:50")
long from = simpleFormat.parse(fromDate).getTime()
long to = simpleFormat.parse(toDate).getTime()
int minutes = (int) ((to - from)/(1000 * 60))
现在是2004-03-26 13：31：40过去是：2004-01-02 11：30：24
要获得两个日期差，差的形式为：XX天XX小时XX分XX秒
方法一：
DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
try
{
Date d1 = df.parse("2004-03-26 13:31:40")
Date d2 = df.parse("2004-01-02 11:30:24")
long diff = d1.getTime() - d2.getTime()
long days = diff / (1000 * 60 * 60 * 24)
}
catch (Exception e)
{
}
方法二：
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
java.util.Date now = df.parse("2004-03-26 13:31:40")
java.util.Date date=df.parse("2004-01-02 11:30:24")
long l=now.getTime()-date.getTime()
long day=l/(24*60*60*1000)
long hour=(l/(60*60*1000)-day*24)
long min=((l/(60*1000))-day*24*60-hour*60)
long s=(l/1000-day*24*60*60-hour*60*60-min*60)
System.out.println(""+day+"天"+hour+"小时"+min+"分"+s+"秒")
方法三：
SimpleDateFormat dfs = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
java.util.Date begin=dfs.parse("2004-01-02 11:30:24")
java.util.Date end = dfs.parse("2004-03-26 13:31:40")
long between=(end.getTime()-begin.getTime())/1000//除以1000是为了转换成秒
long day1=between/(24*3600)
long hour1=between%(24*3600)/3600
long minute1=between%3600/60
long second1=between%60/60
System.out.println(""+day1+"天"+hour1+"小时"+minute1+"分"+second1+"秒")
====================================================
java 比较时间大小
String s1="2008-01-25 09:12:09"
String s2="2008-01-29 09:12:11"
java.text.DateFormat df=new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
java.util.Calendar c1=java.util.Calendar.getInstance()
java.util.Calendar c2=java.util.Calendar.getInstance()
try
{
c1.setTime(df.parse(s1))
c2.setTime(df.parse(s2))
}catch(java.text.ParseException e){
System.err.println("格式不正确")
}
int result=c1.compareTo(c2)
if(result==0)
System.out.println("c1相等c2")
else if(result<0)
System.out.println("c1小于c2")
else
System.out.println("c1大于c2")
