자바 지정 날짜 플러스 일수

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 *   ：java        
 */
public class demo {

	public static void main(String[] args) throws ParseException {
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //     
		Date date = dateFormat.parse("2017-12-10 13:31:00"); //     
		Date newDate = addDate(date, 10); //       10 
		System.out.println(dateFormat.format(date));//          
		System.out.println(dateFormat.format(newDate));
	}

	public static Date addDate(Date date, long day) throws ParseException {
		long time = date.getTime(); //           
		day = day * 24 * 60 * 60 * 1000; //             
		time += day; //          
		return new Date(time); //          
	}

}