日期比较

Date shsj1 = new Date();
Date shsj2 = new Date();

Calendar instance1 = Calendar.getInstance();
Calendar instance2 = Calendar.getInstance();

instance1.setTime(shsj1);
instance2.setTime(shsj2);

if（instance1.compareTo(instance2)==1）{
　　sout.println(">");
}

if（instance1.compareTo(instance2)==0）{
　　sout.println("=");
}

if（instance1.compareTo(instance2)==-1）{
　　sout.println("<");
}