基于位置的时区检索

时间:2010-03-09 01:12:18

标签: java timezone

鉴于:LDAP存储用户的位置。

如何使用他们的位置驾驶他们的时区?接受任何指针,首选Java语言。

提前致谢。

4 个答案:

答案 0 :(得分:8)

这取决于“位置”包含的信息?您需要将位置映射到时区名称,最好是Olson样式时区名称,因为它们更详细,更容易映射,因为它们本身就是位置。

如果它是一个近似地址(如国家和城市等),那么几个地理位置服务确实在其信息中包含时区,因此您可以调用这些服务并查看。

如果它是具有纬度和经度的地理位置,那么名为Earthtools的网站可以为您提供时区。 http://www.earthtools.org/webservices.htm#timezone

此数据库提供从城市和国家/地区到时区的映射:http://citytimezones.info/cms/pending_requests.htm

不幸的是,它使用Windows时区名称,但您可以使用Unicode.org中的此数据http://unicode.org/repos/cldr/trunk/common/supplemental/windowsZones.xml来映射Windows时区名称和Olson TZ名称。

答案 1 :(得分:0)

我实际上并没有这样做,但以下情况应该有效:

  1. 您可以先使用GeoGoogle java库从城邦国家获取经度/纬度。

  2. 接下来,您可以使用Lennart提到的EarthTools(以及您自己的一些Java代码)来获取时区:)

答案 2 :(得分:0)

我们正在使用MaxMind GeoIP database获取有关用户位置的信息。他们有付费版本(准确率为99.8%)以及free version(准确率为99.5%)。

它们还为您提供Java,C,PHP等API,使您能够查询其可以下载并保存在本地的数据库(每月提供更新)。该数据库根据IP地址为您提供有关客户城市,州,国家等的信息。

希望这有帮助。

答案 3 :(得分:0)

 Try this code for use Google Time Zone API from Java:
String get_xml_server_reponse(String server_url){

    URL xml_server = null;

    String xmltext = "";

    InputStream input;


    try {
        xml_server = new URL(server_url);


        try {
            input = xml_server.openConnection().getInputStream();


            final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
            final StringBuilder sBuf = new StringBuilder();

            String line = null;
            try {
                while ((line = reader.readLine()) != null) 
                {
                    sBuf.append(line);
                }
               } 
            catch (IOException e) 
              {
                    Log.e(e.getMessage(), "XML parser, stream2string 1");
              } 
            finally {
                try {
                    input.close();
                    }
                catch (IOException e) 
                {
                    Log.e(e.getMessage(), "XML parser, stream2string 2");
                }
            }

            xmltext =  sBuf.toString();

        } catch (IOException e1) {

                e1.printStackTrace();
            }


        } catch (MalformedURLException e1) {

          e1.printStackTrace();
        }

     return  xmltext;

  }     


 private String get_UTC_Datetime_from_timestamp(long timeStamp){

    try{

        Calendar cal = Calendar.getInstance();
        TimeZone tz = cal.getTimeZone();

        int tzt = tz.getOffset(System.currentTimeMillis());

        timeStamp -= tzt;

        // DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault());
        DateFormat sdf = new SimpleDateFormat();
        Date netDate = (new Date(timeStamp));
        return sdf.format(netDate);
    }
    catch(Exception ex){
        return "";
     }
    } 

 class NTP_UTC_Time
 {
     private static final String TAG = "SntpClient";

     private static final int RECEIVE_TIME_OFFSET = 32;
     private static final int TRANSMIT_TIME_OFFSET = 40;
     private static final int NTP_PACKET_SIZE = 48;

     private static final int NTP_PORT = 123;
     private static final int NTP_MODE_CLIENT = 3;
     private static final int NTP_VERSION = 3;

     // Number of seconds between Jan 1, 1900 and Jan 1, 1970
     // 70 years plus 17 leap days
     private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;

     private long mNtpTime;

     public boolean requestTime(String host, int timeout) {
         try {
             DatagramSocket socket = new DatagramSocket();
             socket.setSoTimeout(timeout);
             InetAddress address = InetAddress.getByName(host);
             byte[] buffer = new byte[NTP_PACKET_SIZE];
             DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);

             buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3);

             writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET);

             socket.send(request);

             // read the response
             DatagramPacket response = new DatagramPacket(buffer, buffer.length);
             socket.receive(response);          
             socket.close();

             mNtpTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET);            
         } catch (Exception e) {
           //  if (Config.LOGD) Log.d(TAG, "request time failed: " + e);
             return false;
         }

         return true;
     }


     public long getNtpTime() {
         return mNtpTime;
     }


     /**
      * Reads an unsigned 32 bit big endian number from the given offset in the buffer.
      */
     private long read32(byte[] buffer, int offset) {
         byte b0 = buffer[offset];
         byte b1 = buffer[offset+1];
         byte b2 = buffer[offset+2];
         byte b3 = buffer[offset+3];

         // convert signed bytes to unsigned values
         int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0);
         int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1);
         int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2);
         int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3);

         return ((long)i0 << 24) + ((long)i1 << 16) + ((long)i2 << 8) + (long)i3;
     }

     /**
      * Reads the NTP time stamp at the given offset in the buffer and returns 
      * it as a system time (milliseconds since January 1, 1970).
      */    
     private long readTimeStamp(byte[] buffer, int offset) {
         long seconds = read32(buffer, offset);
         long fraction = read32(buffer, offset + 4);
         return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L);        
     }

     /**
      * Writes 0 as NTP starttime stamp in the buffer. --> Then NTP returns Time OFFSET since 1900
      */    
     private void writeTimeStamp(byte[] buffer, int offset) {        
         int ofs =  offset++;

         for (int i=ofs;i<(ofs+8);i++)
           buffer[i] = (byte)(0);             
     }

 }

 String get_time_zone_time(GeoPoint gp){

        String erg = "";
        String raw_offset = "";
        String dst_offset = "";

        double Longitude = gp.getLongitudeE6()/1E6;
        double Latitude = gp.getLatitudeE6()/1E6;

        // String request = "http://ws.geonames.org/timezone?lat="+Latitude+"&lng="+ Longitude+ "&style=full";


        long tsLong = 0; // System.currentTimeMillis()/1000;

        NTP_UTC_Time client = new NTP_UTC_Time();

        if (client.requestTime("pool.ntp.org", 2000)) {              
          tsLong = client.getNtpTime();
        }

        if (tsLong != 0)
        {

        tsLong = tsLong  / 1000;

        // https://maps.googleapis.com/maps/api/timezone/xml?location=39.6034810,-119.6822510&timestamp=1331161200&sensor=true

        String request = "https://maps.googleapis.com/maps/api/timezone/xml?location="+Latitude+","+ Longitude+ "&timestamp="+tsLong +"&sensor=true";

        String xmltext = get_xml_server_reponse(request);

        if(xmltext.compareTo("")!= 0)
        {

         int startpos = xmltext.indexOf("<TimeZoneResponse");
         xmltext = xmltext.substring(startpos);



        XmlPullParser parser;
        try {
            parser = XmlPullParserFactory.newInstance().newPullParser();


             parser.setInput(new StringReader (xmltext));

             int eventType = parser.getEventType();  

             String tagName = "";


             while(eventType != XmlPullParser.END_DOCUMENT) {
                 switch(eventType) {

                     case XmlPullParser.START_TAG:

                           tagName = parser.getName();

                         break;


                     case XmlPullParser.TEXT :


                        if  (tagName.equalsIgnoreCase("raw_offset"))
                          if(raw_offset.compareTo("")== 0)                               
                            raw_offset = parser.getText();  

                        if  (tagName.equalsIgnoreCase("dst_offset"))
                          if(dst_offset.compareTo("")== 0)
                            dst_offset = parser.getText();  


                        break;   

                 }

                 try {
                        eventType = parser.next();
                    } catch (IOException e) {

                        e.printStackTrace();
                    }

                }

                } catch (XmlPullParserException e) {

                    e.printStackTrace();
                    erg += e.toString();
                }

        }      

        int ro = 0;
        if(raw_offset.compareTo("")!= 0)
        { 
            float rof = str_to_float(raw_offset);
            ro = (int)rof;
        }

        int dof = 0;
        if(dst_offset.compareTo("")!= 0)
        { 
            float doff = str_to_float(dst_offset);
            dof = (int)doff;
        }

        tsLong = (tsLong + ro + dof) * 1000;



        erg = get_UTC_Datetime_from_timestamp(tsLong);
        }


  return erg;

}

并将其用于:

GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
String Current_TimeZone_Time = get_time_zone_time(gp);