我正在尝试解析GPX file http://en.wikipedia.org/wiki/GPS_eXchange_Format。我用 JDOM 尝试过,但效果不太好。
SAXBuilder builder = new SAXBuilder();
Document document = builder.build(filename);
Element root = document.getRootElement();
System.out.println("Root:\t" + root.getName());
List<Element> listTrks = root.getChildren("trk");
System.out.println("Count trk:\t" + listTrks.size());
for (Element tmpTrk : listTrks) {
List<Element> listTrkpts = tmpTrk.getChildren("trkpt");
System.out.println("Count pts:\t" + listTrkpts.size());
for (Element tmpTrkpt : listTrkpts) {
System.out.println(tmpTrkpt.getAttributeValue("lat") + ":" + tmpTrkpt.getAttributeValue("lat"));
}
}
我打开了示例文件 http://openstreetmap.org/trace/339421/data(CC-BY-SA打开街道地图) http://www.openstreetmap.org输出只是:
根:gpx
计数 trk: 0
我能做些什么?我应该使用 SAXParserFactory (javax.xml.parsers.SAXParserFactory
)并实现一个 Handler 类?
这是我的 gpx 阅读器。它忽略了一些标签,但我希望它会有所帮助。
package ch.perry.rando.geocode;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
*
* @author perrym
*/
public class GpxReader extends DefaultHandler {
private static final DateFormat TIME_FORMAT
= new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
private List<Trackpoint> track = new ArrayList<Trackpoint>();
private StringBuffer buf = new StringBuffer();
private double lat;
private double lon;
private double ele;
private Date time;
public static Trackpoint[] readTrack(InputStream in) throws IOException {
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setValidating(true);
SAXParser parser = factory.newSAXParser();
GpxReader reader = new GpxReader();
parser.parse(in, reader);
return reader.getTrack();
} catch (ParserConfigurationException e) {
throw new IOException(e.getMessage());
} catch (SAXException e) {
throw new IOException(e.getMessage());
}
}
public static Trackpoint[] readTrack(File file) throws IOException {
InputStream in = new FileInputStream(file);
try {
return readTrack(in);
} finally {
in.close();
}
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
buf.setLength(0);
if (qName.equals("trkpt")) {
lat = Double.parseDouble(attributes.getValue("lat"));
lon = Double.parseDouble(attributes.getValue("lon"));
}
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if (qName.equals("trkpt")) {
track.add(Trackpoint.fromWGS84(lat, lon, ele, time));
} else if (qName.equals("ele")) {
ele = Double.parseDouble(buf.toString());
} else if (qName.equals("")) {
try {
time = TIME_FORMAT.parse(buf.toString());
} catch (ParseException e) {
throw new SAXException("Invalid time " + buf.toString());
}
}
}
@Override
public void characters(char[] chars, int start, int length)
throws SAXException {
buf.append(chars, start, length);
}
private Trackpoint[] getTrack() {
return track.toArray(new Trackpoint[track.size()]);
}
}
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