如何使用 Java 读取 JPEG 文件属性？

How to read JPEG file attributes with Java?

提问by Sujeeth

I want to read information from an image (jpg) which has some extra information included from a digital camera like creation date, focus, flash on off, ... How can I get this information.

我想从一个图像 (jpg) 中读取信息，其中包含来自数码相机的一些额外信息，如创建日期、焦点、闪光灯关闭……我如何获得这些信息。

My first idea was.

我的第一个想法是。

BufferedImage image = ImageIO.read(filePicture);
if (image().getPropertyNames() != null) {
    for (int j = 0; j < image().getPropertyNames().length; j++) {
        String key = image().getPropertyNames()[j];
        String value = (String) image().getProperty(key);
        System.out.println(key + ": " + value);
    }
}

But the getPropertyNames() returns null!

但是 getPropertyNames() 返回 null！

回答by Daniel Ruf

I would suggest using http://commons.apache.org/proper/commons-imaging/which can read EXIF data and other formats (IPTC, XMP ...)

我建议使用http://commons.apache.org/proper/commons-imaging/它可以读取 EXIF 数据和其他格式（IPTC、XMP ...）

there are also some examples: http://commons.apache.org/proper/commons-imaging/sampleusage.html

还有一些例子：http: //commons.apache.org/proper/commons-imaging/sampleusage.html

What you need: https://svn.apache.org/repos/asf/commons/proper/imaging/trunk/src/test/java/org/apache/commons/imaging/examples/MetadataExample.java

你需要什么：https: //svn.apache.org/repos/asf/commons/proper/imaging/trunk/src/test/java/org/apache/commons/imaging/examples/MetadataExample.java

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package org.apache.commons.imaging.examples;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.apache.commons.imaging.ImageReadException;
import org.apache.commons.imaging.Imaging;
import org.apache.commons.imaging.common.ImageMetadata;
import org.apache.commons.imaging.common.ImageMetadata.ImageMetadataItem;
import org.apache.commons.imaging.common.RationalNumber;
import org.apache.commons.imaging.formats.jpeg.JpegImageMetadata;
import org.apache.commons.imaging.formats.tiff.TiffField;
import org.apache.commons.imaging.formats.tiff.TiffImageMetadata;
import org.apache.commons.imaging.formats.tiff.constants.ExifTagConstants;
import org.apache.commons.imaging.formats.tiff.constants.GpsTagConstants;
import org.apache.commons.imaging.formats.tiff.constants.TiffTagConstants;
import org.apache.commons.imaging.formats.tiff.taginfos.TagInfo;

public class MetadataExample {
    public static void metadataExample(final File file) throws ImageReadException,
            IOException {
        // get all metadata stored in EXIF format (ie. from JPEG or TIFF).
        final ImageMetadata metadata = Imaging.getMetadata(file);

        // System.out.println(metadata);

        if (metadata instanceof JpegImageMetadata) {
            final JpegImageMetadata jpegMetadata = (JpegImageMetadata) metadata;

            // Jpeg EXIF metadata is stored in a TIFF-based directory structure
            // and is identified with TIFF tags.
            // Here we look for the "x resolution" tag, but
            // we could just as easily search for any other tag.
            //
            // see the TiffConstants file for a list of TIFF tags.

            System.out.println("file: " + file.getPath());

            // print out various interesting EXIF tags.
            printTagValue(jpegMetadata, TiffTagConstants.TIFF_TAG_XRESOLUTION);
            printTagValue(jpegMetadata, TiffTagConstants.TIFF_TAG_DATE_TIME);
            printTagValue(jpegMetadata,
                    ExifTagConstants.EXIF_TAG_DATE_TIME_ORIGINAL);
            printTagValue(jpegMetadata, ExifTagConstants.EXIF_TAG_DATE_TIME_DIGITIZED);
            printTagValue(jpegMetadata, ExifTagConstants.EXIF_TAG_ISO);
            printTagValue(jpegMetadata,
                    ExifTagConstants.EXIF_TAG_SHUTTER_SPEED_VALUE);
            printTagValue(jpegMetadata,
                    ExifTagConstants.EXIF_TAG_APERTURE_VALUE);
            printTagValue(jpegMetadata,
                    ExifTagConstants.EXIF_TAG_BRIGHTNESS_VALUE);
            printTagValue(jpegMetadata,
                    GpsTagConstants.GPS_TAG_GPS_LATITUDE_REF);
            printTagValue(jpegMetadata, GpsTagConstants.GPS_TAG_GPS_LATITUDE);
            printTagValue(jpegMetadata,
                    GpsTagConstants.GPS_TAG_GPS_LONGITUDE_REF);
            printTagValue(jpegMetadata, GpsTagConstants.GPS_TAG_GPS_LONGITUDE);

            System.out.println();

            // simple interface to GPS data
            final TiffImageMetadata exifMetadata = jpegMetadata.getExif();
            if (null != exifMetadata) {
                final TiffImageMetadata.GPSInfo gpsInfo = exifMetadata.getGPS();
                if (null != gpsInfo) {
                    final String gpsDescription = gpsInfo.toString();
                    final double longitude = gpsInfo.getLongitudeAsDegreesEast();
                    final double latitude = gpsInfo.getLatitudeAsDegreesNorth();

                    System.out.println("    " + "GPS Description: "
                            + gpsDescription);
                    System.out.println("    "
                            + "GPS Longitude (Degrees East): " + longitude);
                    System.out.println("    "
                            + "GPS Latitude (Degrees North): " + latitude);
                }
            }

            // more specific example of how to manually access GPS values
            final TiffField gpsLatitudeRefField = jpegMetadata
                    .findEXIFValueWithExactMatch(GpsTagConstants.GPS_TAG_GPS_LATITUDE_REF);
            final TiffField gpsLatitudeField = jpegMetadata
                    .findEXIFValueWithExactMatch(GpsTagConstants.GPS_TAG_GPS_LATITUDE);
            final TiffField gpsLongitudeRefField = jpegMetadata
                    .findEXIFValueWithExactMatch(GpsTagConstants.GPS_TAG_GPS_LONGITUDE_REF);
            final TiffField gpsLongitudeField = jpegMetadata
                    .findEXIFValueWithExactMatch(GpsTagConstants.GPS_TAG_GPS_LONGITUDE);
            if (gpsLatitudeRefField != null && gpsLatitudeField != null
                    && gpsLongitudeRefField != null
                    && gpsLongitudeField != null) {
                // all of these values are strings.
                final String gpsLatitudeRef = (String) gpsLatitudeRefField.getValue();
                final RationalNumber gpsLatitude[] = (RationalNumber[]) (gpsLatitudeField
                        .getValue());
                final String gpsLongitudeRef = (String) gpsLongitudeRefField
                        .getValue();
                final RationalNumber gpsLongitude[] = (RationalNumber[]) gpsLongitudeField
                        .getValue();

                final RationalNumber gpsLatitudeDegrees = gpsLatitude[0];
                final RationalNumber gpsLatitudeMinutes = gpsLatitude[1];
                final RationalNumber gpsLatitudeSeconds = gpsLatitude[2];

                final RationalNumber gpsLongitudeDegrees = gpsLongitude[0];
                final RationalNumber gpsLongitudeMinutes = gpsLongitude[1];
                final RationalNumber gpsLongitudeSeconds = gpsLongitude[2];

                // This will format the gps info like so:
                //
                // gpsLatitude: 8 degrees, 40 minutes, 42.2 seconds S
                // gpsLongitude: 115 degrees, 26 minutes, 21.8 seconds E

                System.out.println("    " + "GPS Latitude: "
                        + gpsLatitudeDegrees.toDisplayString() + " degrees, "
                        + gpsLatitudeMinutes.toDisplayString() + " minutes, "
                        + gpsLatitudeSeconds.toDisplayString() + " seconds "
                        + gpsLatitudeRef);
                System.out.println("    " + "GPS Longitude: "
                        + gpsLongitudeDegrees.toDisplayString() + " degrees, "
                        + gpsLongitudeMinutes.toDisplayString() + " minutes, "
                        + gpsLongitudeSeconds.toDisplayString() + " seconds "
                        + gpsLongitudeRef);

            }

            System.out.println();

            final List<ImageMetadataItem> items = jpegMetadata.getItems();
            for (int i = 0; i < items.size(); i++) {
                final ImageMetadataItem item = items.get(i);
                System.out.println("    " + "item: " + item);
            }

            System.out.println();
        }
    }

    private static void printTagValue(final JpegImageMetadata jpegMetadata,
            final TagInfo tagInfo) {
        final TiffField field = jpegMetadata.findEXIFValueWithExactMatch(tagInfo);
        if (field == null) {
            System.out.println(tagInfo.name + ": " + "Not Found.");
        } else {
            System.out.println(tagInfo.name + ": "
                    + field.getValueDescription());
        }
    }

}

回答by Drew Noakes

Another simple option is to use metadata-extractor:

另一个简单的选择是使用metadata-extractor：

Metadata metadata = ImageMetadataReader.readMetadata(imagePath);

To iterate all values in the file:

迭代文件中的所有值：

for (Directory directory : metadata.getDirectories()) {
    for (Tag tag : directory.getTags()) {
        System.out.println(tag);
    }
}

You can also read specific values from specific directories:

您还可以从特定目录中读取特定值：

// obtain the Exif SubIFD directory
ExifSubIFDDirectory directory 
    = metadata.getFirstDirectoryOfType(ExifSubIFDDirectory.class);

// query the datetime tag's value
Date date = directory.getDate(ExifSubIFDDirectory.TAG_DATETIME_ORIGINAL);

The library is available for Maven users too.

该库也可供 Maven 用户使用。

(Full disclosure: I am the author of this library)

（完全披露：我是这个库的作者）

回答by inor

As others have suggested use http://commons.apache.org/proper/commons-imaging

正如其他人建议使用http://commons.apache.org/proper/commons-imaging

Download the jar from: https://repo.adobe.com/nexus/content/repositories/public/org/apache/commons/commons-imaging/1.0-R1534292/

从以下位置下载 jar：https: //repo.adobe.com/nexus/content/repositories/public/org/apache/commons/commons-imaging/1.0-R1534292/

You can see all the tags here: https://commons.apache.org/proper/commons-imaging/javadocs/api-release/org/apache/sanselan/formats/tiff/constants/AllTagConstants.html

您可以在此处查看所有标签：https: //commons.apache.org/proper/commons-imaging/javadocs/api-release/org/apache/sanselan/formats/tiff/constants/AllTagConstants.html

Here is how you would get the manufacturer and the model:

以下是获取制造商和型号的方法：

String fullFileName="D:/test/photos - orig/lg/20170204_143925.jpg";
File file = new File(fullFileName);

// get all metadata stored in EXIF format (ie. from JPEG or TIFF).
final IImageMetadata metadata = Imaging.getMetadata(file);

if (metadata instanceof JpegImageMetadata) {
    final JpegImageMetadata jpegMetadata = (JpegImageMetadata) metadata;

    String manufacturer = jpegMetadata.findEXIFValueWithExactMatch(TiffTagConstants.TIFF_TAG_MAKE).getStringValue();
    String model = jpegMetadata.findEXIFValueWithExactMatch(TiffTagConstants.TIFF_TAG_MODEL).getStringValue();
    System.out.println("Manufacturer: "+ manufacturer+", Model: " + model);
}