TimeInterval, 用于计算上次获取时间间隔的时间到当前时间的时间间隔
class="java">
非线程安全版本,用于1个线程里。
public class TimeInterval {
    private long current;
    public TimeInterval() {
        current = System.currentTimeMillis();
    }
    public long get() {
        long last = current;
        current = System.currentTimeMillis();
        return current - last;
    }
}
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线程安全版本,可以用于多个线程并发。
import java.util.concurrent.atomic.AtomicLong;
    private final AtomicLong currentTimeHolder;
    public TimeInterval() {
        currentTimeHolder = new AtomicLong(System.currentTimeMillis());
    }
    public long get() {
        long current = System.currentTimeMillis();
        long last = currentTimeHolder.getAndSet(current);
        return current - last;
    }