java计算时间差及比较时间大小(转)

比如：

现在是2004-03-26 13：31：40       

过去是：2004-01-02 11：30：24

我现在要获得两个日期差，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");

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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");