Java 中两个日期之差

 

public int getDay(String fileName) throws ParseException{

int i = fileName.indexOf("_");

//如果 fileName 没有包含” _ “, 那么返回 -1

if(i != -1){

String filePrefix = fileName.substring(0, i);

Date dateTime = new SimpleDateFormat("yyyyMMddHHmmssSSS").parse(filePrefix);

long nowTime = System.currentTimeMillis();

int day = (int) ((nowTime - dateTime.getTime())/(1000*60*60*24));

return day;

}else{

return -1;

}

}