实现两个日期的相减

import java.text.SimpleDateFormat;
import java.util.Date;

public class EG {

 /**
  * @param args
  */
 public static void main(String[] args) {
  String s1 = "2002/09/14 15:48:37";
    String s2 = "2002/09/14 14:18:37";
    try{
    SimpleDateFormat formatter = new SimpleDateFormat ("yyyy/MM/dd HH:mm:ss");
   
   // ParsePosition pos = new ParsePosition(0);
  //  ParsePosition pos1 = new ParsePosition(0);
    Date dt1=formatter.parse(s1);
    Date dt2=formatter.parse(s2);
    System.out.println("dt1="+dt1);
    System.out.println("dt2="+dt2);
    long l = dt1.getTime() - dt2.getTime();
   // long l1=dt1.getDate()-dt2.getDate();
  //  System.out.println("Hello World!="+new Date(l).toLocaleString());
    System.out.println("Hello World!="+l/1000/60/60);
    }catch(Exception e){
     System.out.println("exception"+e.toString());

            }
}
}