输入日期，距离天数，得到日期

public class Datetest {

/**

*

* @param datestr 日期字符串

* @param day 相对天数，为正数表示之后，为负数表示之前

* @return 指定日期字符串n天之前或者之后的日期

*/

public static java.sql.Date getBeforeAfterDate(String datestr, int day) {

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");

java.sql.Date olddate = null;

try {

df.setLenient(false);

olddate = new java.sql.Date(df.parse(datestr).getTime());

} catch (ParseException e) {

throw new RuntimeException("日期转换错误");

}

Calendar cal = new GregorianCalendar();

cal.setTime(olddate);

int Year = cal.get(Calendar.YEAR);

int Month = cal.get(Calendar.MONTH);

int Day = cal.get(Calendar.DAY_OF_MONTH);

int NewDay = Day + day;

cal.set(Calendar.YEAR, Year);

cal.set(Calendar.MONTH, Month);

cal.set(Calendar.DAY_OF_MONTH, NewDay);

return new java.sql.Date(cal.getTimeInMillis());

}

public static void main(String[] args) {

System.out.println(getBeforeAfterDate("2008-10-05",10000)); //获取2008-10-5之后三天的日期

}

}