查看程序运行时间

long begin = System.currentTimeMillis();
。。。。。 // 你的代码

long end = System.currentTimeMillis();

System.out.println(end-begin); // 结果为毫秒，1秒=1000毫秒

完整的代码

/*
 * @(#)Timing.java
 */
package ds.time;

/**
 * An instance of the class acts like a stop watch for measuring the
 * time required to execute a process;  time is measured in seconds from start to stop
 * using millisecond intervals from the system clock.
 */
public class Timing
{
      // starting and ending time measured in milliseconds
      private long startTime, stopTime;

      /**
		 * Creates an instance with default values 0 for both the start time and
		 * and the stop time.
		 */
		public Timing()
      {
         startTime = stopTime = 0;
      }

      /**
		 * Establishes a starting time for the process by recording the
		 * current millisecond time on the system clock
		 */
      public void start()
      {
         startTime = System.currentTimeMillis();
      }

      /**
		 * Establishes a time in seconds by computing the interval from the start time
		 * to the current time on the system clock.
    	 * @return interval of time from start to stop measured in seconds.
		 */
      public double stop()
      {
         stopTime = System.currentTimeMillis();

         return (stopTime - startTime)/1000.0;
   }
}

function Timing() {
				this.startTime = null;
				this.stopTime = null;

				Timing.prototype.start = function(){
					this.startTime = new Date();
				};

				Timing.prototype.stop = function() {
					this.stopTime = new Date();
					return (this.stopTime.getTime() - this.startTime.getTime()) + 'ms';
				};
			}