public static void main(String[] args){
long curSysTime = System.currentTimeMillis();
System.out.println(curSysTime);
System.out.println(new Date(curSysTime));
//减去一周
long deadtime=curSysTime-7*24*60*60*1000L;
System.out.println(deadtime);
System.out.println(new Date(deadtime));
}