Java簡單日期格式解析-返回錯誤的日期時區問題？

Question

抱歉，我覺得我花了太長時間，感到困惑。

我有以下代碼：

    System.out.println("Time Now: " + new Date());    

    Calendar beginningOfDay = new GregorianCalendar();

    beginningOfDay.set(Calendar.HOUR_OF_DAY, 0);
    beginningOfDay.set(Calendar.MINUTE, 0);
    beginningOfDay.set(Calendar.SECOND, 0);
    beginningOfDay.set(Calendar.MILLISECOND, 0);

    SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");  

    Date specifiedTime = null;
    try{
        specifiedTime = sdf.parse("20:55");     // this time is extracted from interface     
    } catch(ParseException pe){}        // complete this later

    System.out.println("specified time is: " + specifiedTime);

     Calendar runResults = new GregorianCalendar(TimeZone.getDefault());
     if (beginningOfDay.getTimeInMillis() + specifiedTime.getTime() > System.currentTimeMillis())
     {  System.out.println("specified time has not occured yet");
        runResults.setTimeInMillis(beginningOfDay.getTimeInMillis() + specifiedTime.getTime());
        System.out.println("Time to run tests is: " + runResults.getTime()); 
     }
     else
     {  System.out.println("need to run tests tomorrow");
        beginningOfDay.add(Calendar.DATE, 1);       // add a day
        runResults.setTimeInMillis(beginningOfDay.getTimeInMillis() + specifiedTime.getTime());
        System.out.println("Time to run tests is: " + runResults.getTime());  
     }

給出以下輸出：

Time Now: Thu Aug 25 20:17:52 BST 2011
specified time is: Thu Jan 01 20:55:00 GMT 1970
need to run tests tomorrow
Time to run tests is: Fri Aug 26 19:55:00 BST 2011

那么，為什么指定時間解析會在19:55 BST時返回？

我試圖將sdf（simpledateformatter）時區設置為與日歷相同，但似乎不起作用。

理想情況下，我想要的是將任何經過分析的時間（例如“ 20.55”）轉換為本地時區中的時間，如果該時間尚未發生，則將計時器設置為在該時間關閉，否則應該等到第二天。 這是我用來計算計時器啟動TimerTask時間的代碼。 如果有人可以提出更好的解決方案，我將不勝感激。 當本地時間是指定時間中的一個時，計時器應啟動TimerTask。

再次感謝任何幫助。

編輯：

用它來使其工作。 雖然不是很整齊

    Calendar timeNow = new GregorianCalendar();

    String timeNowString = timeNow.getTime().toString();
    String timeNowFirstBit = timeNowString.substring(0, 10); // e.g. "Sat Aug 27"
    String timeNowLastBit =  timeNowString.substring(24); // e.g. "2011"

    String userSpecifiedTime = "14:32";    
    SimpleDateFormat specTimeFormat = new SimpleDateFormat("EEE MMM dd HH:mm yyyy");
    String allNewSpecifiedTime = timeNowFirstBit + " " + userSpecifiedTime + " " +                                                                 timeNowLastBit;

    Date specifiedTime = null;
    try{
    specifiedTime = specTimeFormat.parse(allNewSpecifiedTime);
    }   catch (ParseException pe){}

     Calendar runResults = new GregorianCalendar();
     runResults.setTimeInMillis(specifiedTime.getTime());
     if (specifiedTime.getTime() > System.currentTimeMillis())
     {  System.out.println("specified time has not occured yet");          
     }
     else
     {  System.out.println("need to run tests tomorrow");
        runResults.add(Calendar.DATE, 1);       // add a day          
     }
        System.out.println("Time to run tests is: " + runResults.getTime()); 

Answer 1

嘗試

specifiedTime = new GregorianCalendar();
specifiedTime.set(Calendar.HOUR_OF_DAY, 20 );
specifiedTime.set(Calendar.MINUTE, 55 );
specifiedTime.set(Calendar.SECOND, 0);
specifiedTime.set(Calendar.MILLISECOND, 0);

System.out.println("specified time is: " + specifiedTime.getTime());

要么

try{
  specifiedTime = sdf.parse("20:55");     // this time is extracted from interface 
  beginningOfDay.add(Calendar.MILLISECOND, specifiedTime.getTime());
} catch(ParseException pe){}        // complete this later

Answer 2

原因是在給定的時間內沒有BST 。 “英國夏令時開始於三月的最后一個星期日，結束於十月的最后一個星期日。” 因此，在一月份是格林尼治標准時間-將您的時間移到夏季，一切都會好起來的:)。

盡管有些混亂，但這是一個很好的問題，謝謝。