Date at=new Date();
GregorianCalendar agc= new GregorianCalendar(at.getYear(),at.getMonth(),at.getDate(),at.getHours(),at.getMinutes());
agc.add(GregorianCalendar.DATE, -10);
at=agc.getTime();
SimpleDateFormat asd = new SimpleDateFormat("yyMMddkkmm");
String as = asd.format(at);
System.out.println(as);
GregorianCalendar agc= new GregorianCalendar(at.getYear(),at.getMonth(),at.getDate(),at.getHours(),at.getMinutes());
agc.add(GregorianCalendar.DATE, -10);
at=agc.getTime();
SimpleDateFormat asd = new SimpleDateFormat("yyMMddkkmm");
String as = asd.format(at);
System.out.println(as);
java.util.GregorianCalendar g=new java.util.GregorianCalendar();
g.setTime(new java.util.Date());
g.add(java.util.Calendar.DATE,-10);
System.out.println(df.format(g.getTime()));
java.util.Date preDate=new java.util.Date(theDate.getTimes()-24*60*60*1000);