偶遇java时间解析异常

先贴两个异常，不知大家见过没

 

Exception in thread "pool-1-thread-42" java.lang.NumberFormatException: multiple points
	at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1084)
	at java.lang.Double.parseDouble(Double.java:510)
	at java.text.DigitList.getDouble(DigitList.java:151)
	at java.text.DecimalFormat.parse(DecimalFormat.java:1303)
	at java.text.SimpleDateFormat.subParse(SimpleDateFormat.java:1591)
	at java.text.SimpleDateFormat.parse(SimpleDateFormat.java:1312)
	at java.text.DateFormat.parse(DateFormat.java:335)
	at infoair.obcs.utilities.DateTimeUtils.validateDateTime(DateTimeUtils.java:294)
	at infoair.obcs.utilities.TestThread.run(DateTimeUtils.java:318)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)

 

 

Exception in thread "pool-1-thread-9" java.lang.NumberFormatException: For input string: ""
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
	at java.lang.Long.parseLong(Long.java:431)
	at java.lang.Long.parseLong(Long.java:468)
	at java.text.DigitList.getLong(DigitList.java:177)
	at java.text.DecimalFormat.parse(DecimalFormat.java:1298)
	at java.text.SimpleDateFormat.subParse(SimpleDateFormat.java:1591)
	at java.text.SimpleDateFormat.parse(SimpleDateFormat.java:1312)
	at java.text.DateFormat.parse(DateFormat.java:335)
	at infoair.obcs.utilities.DateTimeUtils.validateDateTime(DateTimeUtils.java:294)
	at infoair.obcs.utilities.TestThread.run(DateTimeUtils.java:318)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:619)

 

最近测试一个服务端连多个客户端时，服务端老是报这样的错误，自己debug又没有事情，于是自己写了个demo

 

class TestThread extends Thread{
	String str = "1251-12-12 03:22:22";
	public void run(){
		while(true){
		 Date date = Test.validateDateTime(str);
		 System.out.println(date);
		 try {
			Thread.sleep(10);
		} catch (InterruptedException e) {
			e.printStackTrace();
			break;
		 }
		}
	}
}


class Test{
   
    public final static SimpleDateFormat dateTimeFormat = new SimpleDateFormat(
			"yyyy-MM-dd HH:mm:ss");
        /**
	 * 
	 * @param dateStr
	 *            String 格式为"yyyy-MM-dd HH:mm:ss"
	 * @return 日期
	 */
	public  static Date validateDateTime(String dateStr) {
		try {
			return dateStr == null || dateStr.equals("") ? null
					: dateTimeFormat.parse(dateStr);
		} catch (ParseException e) {
		//	e.printStackTrace();
			return null;
		}
	}
	
	
	public static void main(String[] args) throws InterruptedException {

		ExecutorService exe = Executors.newCachedThreadPool();
		for (int i = 0; i < 100;i ++){
			exe.execute(new TestThread());
		}
		Thread.sleep(5000);
		exe.shutdownNow();
	}
}

 

测试上面的demo 就发现在多线程下九抛出了上面连个异常，查了下API，上面写着：

 

类 SimpleDateFormat

<!-- Generated by javadoc (build 1.6.0-beta2) on Fri Mar 09 12:51:19 CST 2007 -->

<noscript></noscript>

同步

日期格式是不同步的。建议为每个线程创建独立的格式实例。如果多个线程同时访问一个格式，则它必须是外部同步的。

 

 

谨记，谨记。。。

 

有兴趣的 ，来解释下那个异常是怎么发生的吧

评论

2 楼 mercyblitz 2011-01-20  

线程安全问题啊，SimpleDateFormat要使用原型对象。

1 楼 rocketball 2011-01-20  

http://www.iteye.com/topic/882541
刚讨论过的话题