你的新类:

public class TimeWatch {    
    long starts;

    public static TimeWatch start() {
        return new TimeWatch();
    }

    private TimeWatch() {
        reset();
    }

    public TimeWatch reset() {
        starts = System.currentTimeMillis();
        return this;
    }

    public long time() {
        long ends = System.currentTimeMillis();
        return ends - starts;
    }

    public long time(TimeUnit unit) {
        return unit.convert(time(), TimeUnit.MILLISECONDS);
    }
}

用法:

    TimeWatch watch = TimeWatch.start();
    // do something
    long passedTimeInMs = watch.time();
    long passedTimeInSeconds = watch.time(TimeUnit.SECONDS);

之后，所经过的时间可以转换为任何你喜欢的格式，例如日历

Greetz, 查德

如果您正在编写一个必须处理持续时间的应用程序，那么请查看Joda-Time，它有专门处理持续时间、间隔和周期的类。你的getDuration()方法看起来可以返回一个Joda-Time Interval:

DateTime start = new DateTime(2004, 12, 25, 0, 0, 0, 0);
DateTime end = new DateTime(2005, 1, 1, 0, 0, 0, 0);

public Interval getInterval() {
    Interval interval = new Interval(start, end);
}

如果你喜欢使用Java的日历API，你可以试试这个，

Date startingTime = Calendar.getInstance().getTime();
//later on
Date now = Calendar.getInstance().getTime();
long timeElapsed = now.getTime() - startingTime.getTime();

值得注意的是

System.currentTimeMillis() has only millisecond accuracy at best. At worth its can be 16 ms on some windows systems. It has a lower cost that alternatives < 200 ns. System.nanoTime() is only micro-second accurate on most systems and can jump on windows systems by 100 microseconds (i.e sometimes it not as accurate as it appears) Calendar is a very expensive way to calculate time. (i can think of apart from XMLGregorianCalendar) Sometimes its the most appropriate solution but be aware you should only time long intervals.

为了在Java中实现这一点，应该使用哪些类型?

答:长

public class Stream {
    public long startTime;
    public long endTime;

    public long getDuration() {
        return endTime - startTime;
    }
    // I  would add
    public void start() {
        startTime = System.currentTimeMillis();
    }
    public void stop() {
         endTime = System.currentTimeMillis();
     }
}

用法:

  Stream s = .... 

  s.start();

  // do something for a while 

  s.stop();

  s.getDuration(); // gives the elapsed time in milliseconds. 

这是我对你第一个问题的直接回答。

最后一个“注释”，我建议你使用Joda Time。它包含一个适合您需要的间隔类。

如果您从System.currentTimeMillis()获取时间戳，那么您的时间变量应该是长变量。