java 計算出前多少天的時間值

當前時間2013-11-7 18:17:05

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Date date1 = new Date(new Date().getTime() - 24 * 60 * 60 * 1000);

//Date date1 = new Date(new Date().getTime() - 7*24 * 60 * 60 * 1000);
date1.setHours(00);
date1.setMinutes(00);
date1.setSeconds(00);
Timestamp begs = new Timestamp(date1.getTime());
String str = df.format(begs);

System.out.println("=============="+str);//得到2013-11-6 00:00:00

Date date1 = new Date(new Date().getTime() - 7*24 * 60 * 60 * 1000);
date1.setHours(00);
date1.setMinutes(00);
date1.setSeconds(00);
Timestamp begs = new Timestamp(date1.getTime());
String str = df.format(begs);
System.out.println("=============="+str);//得到2013-10-31 00:00:00