本文实例讲述了Java读取图片EXIF信息的方法。分享给大家供大家参考。具体分析如下:
首先介绍一下什么是EXIF,EXIF是Exchangeable Image File的缩写,这是一种专门为数码相机照片设定的格式。这种格式可以用来记录数字照片的属性信息,例如相机的品牌及型号、相片的拍摄时间、拍摄时所设置 的光圈大小、快门速度、ISO等等信息。除此之外它还能够记录拍摄数据,以及照片格式化方式,这样就可以输出到兼容EXIF格式的外设上,例如照片打印机 等。
目前最常见的支持EXIF信息的图片格式是JPG,很多的图像工具都可以直接显示图片的EXIF信息,包括现在的一些著名的相册网站也提供页面用于 显示照片的EXIF信息。本文主要介绍Java语言如何读取图像的EXIF信息,包括如何根据EXIF信息对图像进行调整以适合用户浏览。
目前最简单易用的EXIF信息处理的Java包是Drew Noakes写的metadata-extractor,该项目最新的版本是2.3.4,支持EXIF 2.2版本。你可以直接从http://www.drewnoakes.com/code/exif/ 下载该项目的最新版本包括其源码。
需要注意的是,并不是每个JPG图像文件都包含有EXIF信息,你可以在Windows资源管理器单击选中图片后,如果该图片包含EXIF信息,则会在属性->摘要中显示出来。
ExifTester.java如下:
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import java.io.File; import java.util.Iterator; import com.drew.imaging.jpeg.JpegMetadataReader; import com.drew.metadata.Directory; import com.drew.metadata.Metadata; import com.drew.metadata.Tag; import com.drew.metadata.exif.ExifDirectory; /** * 测试用于读取图片的EXIF信息 * @author Winter Lau */ public class ExifTester { public static void main(String[] args) throws Exception { File jpegFile = new File( "C:/1.JPG" ); Metadata metadata = JpegMetadataReader.readMetadata(jpegFile); Directory exif = metadata.getDirectory(ExifDirectory. class ); Iterator tags = exif.getTagIterator(); while (tags.hasNext()) { Tag tag = (Tag)tags.next(); System.out.println(tag); } } } |
运行结果:
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[Exif] Make - OLYMPUS OPTICAL CO.,LTD [Exif] Model - u10D,S300D,u300D [Exif] Orientation - Top, left side (Horizontal / normal) [Exif] X Resolution - 72 dots per inch [Exif] Y Resolution - 72 dots per inch [Exif] Resolution Unit - Inch [Exif] Software - 22 - 1012 [Exif] Date/Time - 2005 : 04 : 14 13 : 47 : 10 [Exif] YCbCr Positioning - Datum point [Exif] Exposure Time - 0.01 sec [Exif] F-Number - F5. 2 [Exif] Exposure Program - Program creative (slow program) [Exif] ISO Speed Ratings - 80 [Exif] Exif Version - 2.20 [Exif] Date/Time Original - 2005 : 04 : 14 13 : 47 : 10 [Exif] Date/Time Digitized - 2005 : 04 : 14 13 : 47 : 10 [Exif] Components Configuration - YCbCr [Exif] Exposure Bias Value - 0 EV [Exif] Max Aperture Value - F3. 1 [Exif] Metering Mode - Multi-segment [Exif] Light Source - Unknown [Exif] Flash - Flash did not fire, auto [Exif] Focal Length - 17.4 mm [Exif] User Comment - [Exif] FlashPix Version - 1.00 [Exif] Color Space - sRGB [Exif] Exif Image Width - 1024 pixels [Exif] Exif Image Height - 768 pixels [Exif] File Source - Digital Still Camera (DSC) [Exif] Windows XP Title - 风景 [Exif] Windows XP Author - 一路风尘 [Exif] Windows XP Keywords - 你是我的唯一 [Exif] Windows XP Subject - 我的第一张 [Exif] Custom Rendered - Normal process [Exif] Exposure Mode - Auto exposure [Exif] White Balance - Auto white balance [Exif] Digital Zoom Ratio - 1 [Exif] Scene Capture Type - Landscape [Exif] Gain Control - None [Exif] Contrast - None [Exif] Saturation - None [Exif] Sharpness - None [Exif] Unknown tag ( 0xc4a5 ) - 80 114 105 110 116 73 77 0 480 2 - 10 ... [Exif] Compression - JPEG (old-style) [Exif] Thumbnail Offset - 2022 bytes [Exif] Thumbnail Length - 5864 bytes [Exif] Thumbnail Data - [ 5864 bytes of thumbnail data] |
只读取某项信息:
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package test; import java.io.File; import java.util.Iterator; import com.drew.imaging.jpeg.JpegMetadataReader; import com.drew.metadata.Directory; import com.drew.metadata.Metadata; import com.drew.metadata.Tag; import com.drew.metadata.exif.ExifDirectory; /** * 测试用于读取图片的EXIF信息 * @author Winter Lau */ public class PicExif { public static void main(String[] args) throws Exception { File jpegFile = new File( "C:/1.JPG" ); Metadata metadata = JpegMetadataReader.readMetadata(jpegFile); Directory exif = metadata.getDirectory(ExifDirectory. class ); Iterator tags = exif.getTagIterator(); if (exif.containsTag(ExifDirectory.TAG_WIN_AUTHOR)){ System.out.println( "Pic author is " +exif.getDescription(ExifDirectory.TAG_WIN_AUTHOR)); } if (exif.containsTag(ExifDirectory.TAG_WIN_TITLE)){ System.out.println( "Pic title is " +exif.getDescription(ExifDirectory.TAG_WIN_TITLE)); } if (exif.containsTag(ExifDirectory.TAG_WIN_KEYWORDS)){ System.out.println( "Pic keyword is " +exif.getDescription(ExifDirectory.TAG_WIN_KEYWORDS)); } } } |
希望本文所述对大家的java程序设计有所帮助。