import org.apache.sanselan.common.ImageMetadata; //导入依赖的package包/类
public IImageMetadata getMetadata(ByteSource byteSource, Map params)
        throws ImageReadException, IOException
{
    ArrayList chunks = readChunks(byteSource, new int[] { tEXt, zTXt, },
            true);

    if ((chunks == null) || (chunks.size() < 1))
        return null;

    ImageMetadata result = new ImageMetadata();

    for (int i = 0; i < chunks.size(); i++)
    {
        PNGTextChunk chunk = (PNGTextChunk) chunks.get(i);

        result.add(chunk.getKeyword(), chunk.getText());
    }

    return result;
}
 

import org.apache.sanselan.common.ImageMetadata; //导入依赖的package包/类
/**
 * @param metadata
 * @param image
 * @return Whether any properties has been updated
 */
private boolean addSanselanProperties(IImageMetadata metadata, Image image) throws Exception {
	boolean isSomethingDifferent = false;
	if (metadata instanceof JpegImageMetadata) {
		JpegImageMetadata jpegMetadata = (JpegImageMetadata) metadata;
		StringBuffer keywords = null;
		StringBuffer spatial = null;

		for (Object o : jpegMetadata.getItems()) {
			if (o instanceof ImageMetadata.Item) {
				ImageMetadata.Item item = (ImageMetadata.Item) o;
				if (item.getKeyword().equals("Object Name") && image.getTitle() == null) {
					image.setTitle(sanitizer.sanitize(item.getText()));
					isSomethingDifferent = true;
				} else if (item.getKeyword().equals("Keywords")) {
					if (keywords == null) {
						keywords = new StringBuffer();
						keywords.append(item.getText());
					} else {
						keywords.append(", " + item.getText());
					}
				} else if (item.getKeyword().equals("Sublocation")
						|| item.getKeyword().equals("Province/State")
						|| item.getKeyword().equals("Country/Primary Location Name")) {
					if (spatial == null) {
						spatial = new StringBuffer();
						spatial.append(item.getText());
					} else {
						spatial.append(", " + item.getText());
					}
				}
			}
		}
		if (spatial != null && image.getSpatial() == null) {
			image.setSpatial(sanitizer.sanitize(spatial.toString()));
			isSomethingDifferent = true;
		}
		if (keywords != null && image.getSubject() == null) {
			image.setSubject(sanitizer.sanitize(keywords.toString()));
			isSomethingDifferent = true;
		}
		if (jpegMetadata.findEXIFValue(TiffConstants.TIFF_TAG_ARTIST) != null
				&& image.getCreator() == null) {
			image.setCreator(sanitizer.sanitize(jpegMetadata.findEXIFValue(
					TiffConstants.TIFF_TAG_ARTIST).getStringValue()));
			isSomethingDifferent = true;
		}
		if (jpegMetadata.findEXIFValue(TiffConstants.TIFF_TAG_COPYRIGHT) != null
				&& image.getRights() == null) {

			image.setRights(sanitizer.sanitize(jpegMetadata.findEXIFValue(
					TiffConstants.TIFF_TAG_COPYRIGHT).getStringValue()));
			isSomethingDifferent = true;
		}
		if (jpegMetadata.findEXIFValue(TiffConstants.TIFF_TAG_IMAGE_DESCRIPTION) != null
				&& image.getDescription() == null) {
			image.setDescription(sanitizer.sanitize(jpegMetadata.findEXIFValue(
					TiffConstants.TIFF_TAG_IMAGE_DESCRIPTION)
					.getStringValue()));
			isSomethingDifferent = true;
		}
		TiffImageMetadata exifMetadata = jpegMetadata.getExif();
		if (exifMetadata != null) {
			TiffImageMetadata.GPSInfo gpsInfo = exifMetadata.getGPS();
			if (gpsInfo != null && image.getLocation() == null) {
				image.setLongitude(gpsInfo.getLongitudeAsDegreesEast());
				image.setLatitude(gpsInfo.getLatitudeAsDegreesNorth());
				isSomethingDifferent = true;
			}
		}
	}
	return isSomethingDifferent ;
}