blocks|key|3013743|text|尝试检查JPEG的编码。例如，ImageIO无法读取CMYK编码的jpeg图像。AFAIK，ImageIO已经很多年没有更新了，所以您想尝试使用官方的替代/扩展：JAI+ImageIO。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3013744|不巧的是，JAI+ImageIO需要安装到JRE中的一些本机库，这可能是不必要的。我们做了以下工作：|3013745|使用阿帕奇桑塞兰来检测，是否是JPEG|unordered-list-item|3013746|由于Sanselan不能读写JPEG，所以使用普通的AWT+JPEGCodec：JPEGCodec.createJPEGDecoder(...)|3013747|要将CMYK转换为RGB，我们需要读取BufferedImage的光栅并手动转换它(您可以使用ICC配置文件，但手动转换符合我们的需要)|3013748|下面是我的一个问题，这是因为ImageIO不支持所有类型的JPEG图像，我在这里更多地说明了我对为什么会收到这样的信息的发现：用纯Java替代JAI+ImageIO检测CMYK图像|3013749|entityMap|0|LINK|mutability|MUTABLE|url|http://java.net/projects/jai-imageio/|1|https://commons.apache.org/proper/commons-imaging/history.html|2|https://stackoverflow.com/questions/6829428/pure-java-alternative-to-jai-imageio-for-detecting-cmyk-images^0|F|7|29|B|0|0|0|2|6|1|0|U|9|14|W|0|J|D|0|E|7|1R|R|2|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|19|8|@]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|K|3|L|5|J|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|M|3|N|5|J|7|1I|8|@$9|1J|A|1K|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1L|8|@$9|1M|A|1N|B|C]]|D|@$9|1O|A|1P|1|1Q]]|E|$]]|$1|Q|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]|10|$5|T|U|V|E|$W|11]]]]

Try to check the encoding of the JPEG. <code>ImageIO</code> can't read CMYK-encoded jpeg images for example.
AFAIK, ImageIO hasn't been updated for years, so you'd like to try and use the official alternative/extension: <a href="http://java.net/projects/jai-imageio/" rel="nofollow noreferrer">JAI ImageIO</a>.

Unforutnately, JAI ImageIO needs some native libraries installed into the JRE, which might be unwanted.
We do the following: 

<ul>
<li>use <a href="https://commons.apache.org/proper/commons-imaging/history.html" rel="nofollow noreferrer">Apache Sanselan</a> to detect, whether it's a JPEG</li>
<li>since Sanselan can't read and write JPEG, use the plain old AWT <code>JPEGCodec</code>: <code>JPEGCodec.createJPEGDecoder(...)</code></li>
<li>to convert CMYK to RGB, we then get the raster of the read <code>BufferedImage</code> and manually convert it (you could use ICC profiles, but the manual conversion fits our needs)</li>
</ul>

Here's a question of mine that resulted of the fact that <code>ImageIO</code> doesn't support all types of JPEG images, and I there stated a little more of my findings of why you get that message: <a href="https://stackoverflow.com/questions/6829428/pure-java-alternative-to-jai-imageio-for-detecting-cmyk-images">Pure Java alternative to JAI ImageIO for detecting CMYK images</a>

blocks|key|3013786|text|不幸的是，我遇到了很多违反JPEG文件的标准。ImageIO特别挑剔，并且经常拒绝加载图像，这些图像通常被加载，并且显然被其他软件正确显示，而对文件格式的检查则不那么严格。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3013787|这不是很漂亮，但解决方法之一是直接使用Oracle内部JPEG解码器(com.sun.image.codec.jpeg.JPEGCodec)，因为它似乎可以容忍更多的规范偏差，如ImageIO包装：|3013788|BufferedImage+img+=+
++++JPEGCodec.createJPEGDecoder(inputStream).decodeAsBufferedImage();|code-block|syntax|javascript|3013789|这当然不是一个理想的解决方案，因为使用特定的实现类会将您锁定到特定的VM供应商，并且可能会与较新的VM版本中断，但是如果您只在受控环境中使用该软件，它可能比根本没有解决方案好。|3013790|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I've unfortunately come across a lot of standard violating JPEG files. ImageIO is particularly picky and often refuse to load images, which are often loaded and apparently displayed correctly by other software with less strict checks on the file format.

It's not very pretty, but one workaround is to use the Oracle VM internal JPEG decoder directly (com.sun.image.codec.jpeg.JPEGCodec), as it seems to tolerate more spec deviations as the ImageIO wrapper:

<pre><code>BufferedImage img = 
 JPEGCodec.createJPEGDecoder(inputStream).decodeAsBufferedImage();
</code></pre>

This is of course not an ideal solution, since using implementation specific classes will lock you to a specific VM vendor and may break with newer VM versions, but if you'll only used the software in a controlled environment, it may be better than no solution at all.

blocks|key|3370438|text|另一种选择是使用由编写的.jar：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3370439|http://www.randelshofer.ch/blog/2011/08/reading-cmyk-jpeg-images-with-java-imageio/或Monte库：http://www.randelshofer.ch/monte/|offset|length|3370440|它看起来非常简单，类似于ImageIO的使用，并且可以在CC许可下使用。|3370441|entityMap|0|LINK|mutability|MUTABLE|url|http://www.randelshofer.ch/blog/2011/08/reading-cmyk-jpeg-images-with-java-imageio/|1|http://www.randelshofer.ch/monte/^0|0|0|2B|0|2J|X|1|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]|$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]|P|$5|K|L|M|A|$N|Q]]]]

Another option is to use .jar prepared by Werner Randelshofer: 

<a href="http://www.randelshofer.ch/blog/2011/08/reading-cmyk-jpeg-images-with-java-imageio/" rel="nofollow">http://www.randelshofer.ch/blog/2011/08/reading-cmyk-jpeg-images-with-java-imageio/</a> or Monte Media Library: <a href="http://www.randelshofer.ch/monte/" rel="nofollow">http://www.randelshofer.ch/monte/</a>

It looks quite easy and similar to ImageIO usage and available under CC license.

blocks|key|3013815|text|要处理特定格式的图像，需要添加相应的依赖项，例如imageio或imageio：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3013816|<dependency>
<groupId>com.twelvemonkeys.imageio</groupId>
<artifactId>imageio-jpeg</artifactId>
<version>3.3.2</version>
</dependency>

<dependency>
<groupId>com.twelvemonkeys.imageio</groupId>
<artifactId>imageio-bmp</artifactId>
<version>3.3.2</version>
</dependency>

<dependency>
<groupId>com.twelvemonkeys.imageio</groupId>
<artifactId>imageio-core</artifactId>
<version>3.3.2</version>
</dependency>|code-block|syntax|javascript|3013817|内置的ImageIO+Java在运行时自动加载插件。|3013818|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

To work with images in a specific format,you need to add the corresponding dependency, such as imageio-jpeg or imageio-tiff:
<pre><code>&lt;dependency&gt;
&lt;groupId&gt;com.twelvemonkeys.imageio&lt;/groupId&gt;
&lt;artifactId&gt;imageio-jpeg&lt;/artifactId&gt;
&lt;version&gt;3.3.2&lt;/version&gt;
&lt;/dependency&gt;

&lt;dependency&gt;
&lt;groupId&gt;com.twelvemonkeys.imageio&lt;/groupId&gt;
&lt;artifactId&gt;imageio-bmp&lt;/artifactId&gt;
&lt;version&gt;3.3.2&lt;/version&gt;
&lt;/dependency&gt;

&lt;dependency&gt;
&lt;groupId&gt;com.twelvemonkeys.imageio&lt;/groupId&gt;
&lt;artifactId&gt;imageio-core&lt;/artifactId&gt;
&lt;version&gt;3.3.2&lt;/version&gt;
&lt;/dependency&gt;
</code></pre>
the built-in ImageIO Java API loads the plugins automatically at runtime.

blocks|key|1816586|text|这个提供教程是一个使用apache库的答案.我发现它是一个更干净的实现。我包括了下面的依赖项|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1816587|<dependency>
++<groupId>commons-io</groupId>
++<artifactId>commons-io</artifactId>
++<version>2.11.0</version>
</dependency>|code-block|syntax|javascript|1816588|下面是在添加依赖项之后工作的代码|1816589|++++public+ResponseEntity<byte[]>+getImage(@PathVariable("filename")+String+filename)+{
+++++byte[]+image+=+new+byte[0];
++++++try+{
++++++++++image+=+FileUtils.readFileToByteArray(new+File(FILE_PATH_ROOT%2Bfilename));
++++++}+catch+(IOException+e)+{
++++++++++e.printStackTrace();
++++++}
++++++return+ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(image);
++++}|1816590|entityMap|0|LINK|mutability|MUTABLE|url|https://javatodev.com/serve-image-stored-in-server-using-spring-boot/^0|2|4|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

This <a href="https://javatodev.com/serve-image-stored-in-server-using-spring-boot/" rel="nofollow noreferrer">tutorial provided</a> an answer using the apache commons IO library. I found it to be a cleaner implementation. I included the dependency below
<pre><code>&lt;dependency&gt;
 &lt;groupId&gt;commons-io&lt;/groupId&gt;
 &lt;artifactId&gt;commons-io&lt;/artifactId&gt;
 &lt;version&gt;2.11.0&lt;/version&gt;
&lt;/dependency&gt;
</code></pre>
Here is the code that worked after adding the dependency
<pre><code> public ResponseEntity&lt;byte[]&gt; getImage(@PathVariable(&quot;filename&quot;) String filename) {
 byte[] image = new byte[0];
 try {
 image = FileUtils.readFileToByteArray(new File(FILE_PATH_ROOT+filename));
 } catch (IOException e) {
 e.printStackTrace();
 }
 return ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(image);
 }
</code></pre>

Working with images in Java for the first time and am getting some bizarro exceptions that aren't documented very well. Here's the line of code that is failing:

<pre><code>BufferedImage imgSelected = ImageIO.read(new File("/abs/url/to/file/image.jpg"));
</code></pre>

This line is throwing an IIOException with Unsupported image type as the exception message. I have checked and re-checked that it is in fact this line throwing the exception, that the File object is valid, that the URL is valid, and that the <code>image.jpg</code> is in fact a valid JPG that loads perfectly fine in other image viewers.

What could I do to get more information about the nature of this exception? Is this the traditional way for loading images in Java 7, or is this an old/deprecating method? There's just not a lot of info out there about these "Unsupported image type" exceptions, and surely, ImageIO supported JPGs!

Thanks for any help!

Java ImageIO IIOException: Unsupported image type?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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第一次在Java中处理图像，并且得到了一些奇怪的异常，这些异常并没有得到很好的记录。下面是失败的代码行：BufferedImage imgSelected = ImageIO.read(new File("/abs/url/to/file/image.jpg"));这一行是抛出一个不受支持的图像类型的IIOExcept...

问Java ImageIO IIOException:不支持的图像类型？
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