public static String getStatetime() throws ParseException{
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
c.add(Calendar.DATE, - 7);
Date monday = c.getTime();
String preMonday = sdf.format(monday);
return preMonday;
}
来自：http://blog.sina.com.cn/s/blog_48fd85de0100gphn.html