java 日期和小时相加减处理

number:为正数是相加,为负数是相减
public static Date reportGetDate(Date d,String type,int number){
Calendar calendar = Calendar.getInstance();
calendar.setTime(d);
if(type.equals("YEAR")) calendar.add(Calendar.YEAR,number);
if(type.equals("MONTH"))calendar.add(Calendar.MONTH,number);
if(type.equals("DAY")) calendar.add(Calendar.DAY_OF_MONTH,number);
if(type.equals("HOUR")) calendar.add(Calendar.HOUR_OF_DAY,number);
Date date = calendar.getTime();
return date;
}