Java日期时间处理常用方法

// 由字符串时间得到Date类型时间
public static Date getDateFrom(String strDate){
try{
SimpleDateFormat sdf =   new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse(strDate);
return date;
}
catch(Exception ex){
return null;
}
}

// 由Date类型时间得到字符串时间
public static String getDateStrFrom(Date date){
try{
Format formatter = new SimpleDateFormat("yyyy-MM-dd");
return formatter.format(date);
}
catch(Exception ex){
return null;
}
}

/**
* 得到几天前的时间
*
* @param d
* @param day
* @return
*/
public static String getDateBefore(Date d, int day) {
Calendar now = Calendar.getInstance();
now.setTime(d);
now.set(Calendar.DATE, now.get(Calendar.DATE) - day);

Format formatter = new SimpleDateFormat("yyyy-MM-dd");
return formatter.format(now.getTime());
}

for(DateRangeHour drh:lsTen){

for(Object obj:ls){
DateHour d=(DateHour)obj;

if(d.getDate().before(drh.getEndDate()) && d.getDate().after(drh.getStartDate())){
drh.hours+=d.getHours();
}
}
}