为什么在这种情况下错误地解释日期

Question

我有一组rss提要，我用rssmix将它们组合在一起。

我面临着日期的问题，日期被错配通过rssmix

由实际的新闻提供商提供的日期是

2016年1月13日获得的实际新闻提供商和日期，上午09时12

凡通过rssmix我得到这个日期

2016年1月13日02:30

我用所有日期的转换，请看这是我的完整程序

import java.net.URL; 
import java.text.ParseException; 
import java.text.SimpleDateFormat; 
import java.util.Date; 
import java.util.Locale; 
import java.util.TimeZone; 

import javax.xml.parsers.DocumentBuilder; 
import javax.xml.parsers.DocumentBuilderFactory; 
import javax.xml.parsers.ParserConfigurationException; 

import org.apache.log4j.Logger; 
import org.json.JSONArray; 
import org.json.JSONObject; 
import org.w3c.dom.Document; 
import org.w3c.dom.Element; 
import org.w3c.dom.NodeList; 

public class Test { 
    private final static Logger logger = Logger.getLogger(Test.class); 
    private static Test instance = null; 
    private static DocumentBuilder builder = null; 
    private static final long DAY = 43200000; 

    // private static final long DAY = 30400000; 

    public Test() { 
    } 

    public static Test getInstance() { 
     if (instance == null) 
      instance = new Test(); 
     return instance; 
    } 

    public static DocumentBuilder getDocumentBuilderInstance() 
      throws ParserConfigurationException { 
     if (builder == null) 
      builder = DocumentBuilderFactory.newInstance().newDocumentBuilder(); 
     return builder; 
    } 

    private static SimpleDateFormat in_newsupdater = new SimpleDateFormat(
      "E,dd MMM yy HH:mm:ss", Locale.ENGLISH); 
    private static SimpleDateFormat out_newsupdater = new SimpleDateFormat(
      "yyyy-MM-dd HH:mm", Locale.ENGLISH); 


    public static void main(String args[]) { 

     try { 
      final JSONArray latestnews = new JSONArray(); 
      builder = getDocumentBuilderInstance(); 
      final URL url = new URL("http://www.rssmix.com/u/8171434/rss.xml"); 
      final Document doc = builder.parse(url.openStream()); 
      final NodeList items = doc.getElementsByTagName("item"); 
      for (int i = 0; i < items.getLength(); i++) { 
       final JSONObject jsonobj_allnews = new JSONObject(); 
       final Element item = (Element) items.item(i); 
       String title = getValue(item, "title"); 

       String link = getValue(item, "link"); 
       String pub_date = getValue(item, "pubDate"); 

       System.out.println("recievied" + pub_date); 

       pub_date = convertdate(pub_date); 

      } 

     } catch (Exception e) { 
      e.printStackTrace(); 
      e.getMessage(); 
     } catch (Throwable e) { 
      e.getMessage(); 
      e.printStackTrace(); 
     } finally { 
     } 
    } 

    public static String convertdate(final String recivieddate) 
      throws ParseException { 

     Date date = in_newsupdater.parse(recivieddate); 
     in_newsupdater.setTimeZone(TimeZone.getTimeZone("GMT")); 
     out_newsupdater.setTimeZone(TimeZone.getTimeZone("Asia/Kolkata")); 
     return out_newsupdater.format(date); 
    } 

    public static String getValue(final Element parent, final String nodeName) { 
     return parent.getElementsByTagName(nodeName).item(0).getFirstChild() 
       .getNodeValue(); 
    } 

} 

可否请你让我知道如何解决这个问题。

Answer 1

您希望格林尼治标准时间（UTC）的时间转换为亚洲/加尔各答的权利。时差是+5.30小时。所以Wed, 13 Jan 2016 02:30:22 +0000将2016-01-13 08:00

SimpleDateFormat in_newsupdater = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z"); 
    SimpleDateFormat out_newsupdater = new SimpleDateFormat("yyyy-MM-dd HH:mm"); 

    Date date = in_newsupdater.parse("Wed, 13 Jan 2016 02:30:22 +0000"); 
    out_newsupdater.setTimeZone(TimeZone.getTimeZone("Asia/Kolkata")); 
    System.out.println(out_newsupdater.format(date));