java计算时间差

SimpleDateFormat simpleFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm");//如2016-08-10 20:40  

1.计算天数差。

    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

    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：

 

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));