extension = "mbstring.so"
extension = "exif.so"
并且确认你的extension_dir值与你安装模块时提示的Installing shared extensions值一致，比如我安装模块时提示我的extensions位置是
复制代码 代码如下:
/usr/local/webserver/php/lib/php/extensions/no-debug-non-zts-20090626/
那么你的php.ini里的extension_dir要指向正确目录
复制代码 代码如下:
extension_dir="/usr/local/webserver/php/lib/php/extensions/no-debug-non-zts-20090626/"
保存php.ini，重启webserver。
打开phpinfo()找到相应属性看看是否已正常工作
正常情况下你会看到如下两个模块信息
使用exif_read_data()读取图片的exif信息
支持读取exif信息的图片类型在phpinfo里已经写明了，只能是jpeg或者tiff类型，其中jpeg是常用类型，这就已经足够。
我们来看看exif_read_data()函数的使用手册
复制代码 代码如下:
array exif_read_data ( string $filename [, string $sections = NULL [, bool $arrays = false [, bool $thumbnail = false ]]] )
参数：
filename ：要读取图片exif信息的图片路径，这里不能是URL
sections：是需要存在于文件中的逗号分隔的区段列表用来产生结果数组。如果未找到所请求的区段则返回值为 FALSE。
FILE
FileName, FileSize, FileDateTime, SectionsFound
COMPUTED
html，Width，Height，IsColor，可能有更多其它的。Height 和 Width 是用和 getimagesize() 一样的方法计算的，因此它们的值不能是任何返回的头信息的部分。此外 html 是一个 height/width 的文本字符串可以用于普通的HTML 中。
ANY_TAG
任何包含有标记的信息，例如 IFD0，EXIF，...
IFD0
所有 IFD0 的标记数据。在标准的图像文件中这包含了图像大小及其它。
THUMBNAIL
如果有第二个 IFD，文件应该包含有缩略图。所有有关嵌入缩略图的标记信息都存储在本区。
COMMENT
JPEG 图像的注释头信息。
EXIF
EXIF 区段是 IFDO 的子区，包含有图像的更多详细信息。大多数内容都是数码相机相关的。
arrays ：指定了是否每个区段都成为一个数组。sections COMPUTED，THUMBNAIL 和COMMENT 区段总是成为数组，因为它们里面包含的名字和其它区段冲突。
thumbnail ： 当设定为 TRUE 时，读取缩略图本身。否则只读取标记数据。
我们来读取一张图片的exif信息试试
复制代码 代码如下:
<?php
$exif = getExif('a.jpg');
echo '<pre>';
print_r($exif);
echo '</pre>';
执行结果：
复制代码 代码如下:
Array
(
[FileName] => a.jpg
[FileDateTime] => 1361340032
[FileSize] => 69170
[FileType] => 2
[MimeType] => image/jpeg
[SectionsFound] => ANY_TAG, IFD0, THUMBNAIL, EXIF, GPS, INTEROP
[COMPUTED] => Array
(
[html] =>
[Height] => 397
[Width] => 600
[IsColor] => 1
[ByteOrderMotorola] => 1
[ApertureFNumber] => f/13.0
[FocusDistance] => 3.76m
[UserComment] =>
[UserCommentEncoding] => ASCII
[Copyright] =>
[Thumbnail.FileType] => 2
[Thumbnail.MimeType] => image/jpeg
)
[ImageWidth] => 4928
[ImageLength] => 3264
[BitsPerSample] => Array
(
[0] => 8
[1] => 8
[2] => 8
)
[PhotometricInterpretation] => 2
[Make] => NIKON CORPORATION
[Model] => NIKON D7000
[Orientation] => 1
[SamplesPerPixel] => 3
[XResolution] => 3000000/10000
[YResolution] => 3000000/10000
[ResolutionUnit] => 2
[Software] => Adobe Photoshop CS5 Windows
[DateTime] => 2013:02:18 20:50:46
[WhitePoint] => Array
(
[0] => 313/1000
[1] => 329/1000
)
[PrimaryChromaticities] => Array
(
[0] => 64/100
[1] => 33/100
[2] => 21/100
[3] => 71/100
[4] => 15/100
[5] => 6/100
)
[YCbCrCoefficients] => Array
(
[0] => 299/1000
[1] => 587/1000
[2] => 114/1000
)
[YCbCrPositioning] => 2
[Copyright] =>
[Exif_IFD_Pointer] => 500
[GPS_IFD_Pointer] => 1248
[THUMBNAIL] => Array
(
[Compression] => 6
[XResolution] => 72/1
[YResolution] => 72/1
[ResolutionUnit] => 2
[JPEGInterchangeFormat] => 1362
[JPEGInterchangeFormatLength] => 4784
)
[ExposureTime] => 40/10
[FNumber] => 130/10
[ExposureProgram] => 1
[ISOSpeedRatings] => 1000
[UndefinedTag:0x8830] => 2
[ExifVersion] => 0230
[DateTimeOriginal] => 2013:02:14 21:12:08
[DateTimeDigitized] => 2013:02:14 21:12:08
[ComponentsConfiguration] =>
[CompressedBitsPerPixel] => 4/1
[ShutterSpeedValue] => -2/1
[ApertureValue] => 7400879/1000000
[ExposureBiasValue] => 2/6
[MaxApertureValue] => 36/10
[SubjectDistance] => 376/100
[MeteringMode] => 3
[LightSource] => 0
[Flash] => 16
[FocalLength] => 180/10
[UserComment] => ASCII
[SubSecTime] => 10
[SubSecTimeOriginal] => 10
[SubSecTimeDigitized] => 10
[FlashPixVersion] => 0100
[ColorSpace] => 65535
[ExifImageWidth] => 600
[ExifImageLength] => 397
[InteroperabilityOffset] => 1216
[SensingMethod] => 2
[FileSource] =>
[SceneType] =>
[CFAPattern] =>
[CustomRendered] => 0
[ExposureMode] => 1
[WhiteBalance] => 0
[DigitalZoomRatio] => 1/1
[FocalLengthIn35mmFilm] => 27
[SceneCaptureType] => 0
[GainControl] => 2
[Contrast] => 0
[Saturation] => 0
[Sharpness] => 0
[SubjectDistanceRange] => 0
[UndefinedTag:0xA500] => 22/10
[GPSVersion] =>
[InterOperabilityIndex] => R03
[InterOperabilityVersion] => 0100
)
如果提示：
复制代码 代码如下: