Java--时间处理

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

 class timeTest{
    public static void main(String[] args){
        //获取当前时间
        Date start=new Date();
        //格式化日期、时间
        SimpleDateFormat df=new SimpleDateFormat("yyyyMMddHHmmss");
        //String s=String.format("yyyy-MM-dd", dt);
        String s=df.format(start);
        System.out.println(s);

        //计算时间差
        Date end=new Date();
        long diff = end.getTime() - start.getTime();
        String info=String.format("it takes %f seconds to run.", diff / 1000.00);
        System.out.println(info);
    }
}