java计算时间差

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=between600/60;
 long second1=between`/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");