string 日期相加和相减

//	calendar.roll(Calendar.DAY_OF_MONTH, 1);//加一天
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class TestTime {
	public static void main(String[] args) {
		String d = "2004-1-1";
		DateFormat df = new SimpleDateFormat("yyyy-MM-dd");/*** 加一天*/
		try {
			Date dd = df.parse(d);
			Calendar calendar = Calendar.getInstance();
			calendar.setTime(dd);
			calendar.add(Calendar.DAY_OF_MONTH, 1);//加一天
			System.out.println("增加一天之后：" + df.format(calendar.getTime()));
		} catch (ParseException e) {
			e.printStackTrace();
		}
		/*** 减一天*/
		try {
			long dif = df.parse(d).getTime()-86400*1000;//减一天
			Date date=new Date();02
			date.setTime(dif);
			System.out.println("减少一天之后：" + df.format(date));
		} catch (ParseException e) {
			e.printStackTrace();
		}
	}
}