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<TITLE>Determining If an Image Format Can Be Read or Written (Java Developers Almanac Example)
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<h1>The Java Developers Almanac 1.4</h1>
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<B><A HREF="../javax.imageio/pkg.html">javax.imageio</A></B><font color="#666666" class="xsmall-font">
[6 examples]
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<h3>e697. Determining If an Image Format Can Be Read or Written</h3>
By default, the javax.imageio package can read GIF, PNG, and JPEG
images and can write PNG and JPEG images. This example demonstrates
how to determine if a particular image format can be either read or
written using the <code>javax.imageio</code> package.
<pre> boolean b;
// Check availability using a format name
b = canReadFormat("foo"); // false
b = canReadFormat("gif"); // true
b = canReadFormat("giF"); // true
b = canWriteFormat("foo"); // false
b = canWriteFormat("gif"); // false
b = canWriteFormat("PNG"); // true
b = canWriteFormat("jPeG"); // true
// Get extension from a File object
File f = new File(<font color="#0066ff"><i>"image.jpg"</i></font>);
String s = f.getName().substring(f.getName().lastIndexOf('.')+1);
// Check availability using a filename extension
b = canReadExtension(s);
b = canWriteExtension(s);
// Check availability using a MIME type
b = canReadMimeType("image/jpg"); // false
b = canReadMimeType("image/jpeg"); // true
b = canWriteMimeType("image/gif"); // false
b = canWriteMimeType("image/jPeg"); // true
// Returns true if the specified format name can be read
public static boolean canReadFormat(String formatName) {
Iterator iter = ImageIO.getImageReadersByFormatName(formatName);
return iter.hasNext();
}
// Returns true if the specified format name can be written
public static boolean canWriteFormat(String formatName) {
Iterator iter = ImageIO.getImageWritersByFormatName(formatName);
return iter.hasNext();
}
// Returns true if the specified file extension can be read
public static boolean canReadExtension(String fileExt) {
Iterator iter = ImageIO.getImageReadersBySuffix(fileExt);
return iter.hasNext();
}
// Returns true if the specified file extension can be written
public static boolean canWriteExtension(String fileExt) {
Iterator iter = ImageIO.getImageWritersBySuffix(fileExt);
return iter.hasNext();
}
// Returns true if the specified mime type can be read
public static boolean canReadMimeType(String mimeType) {
Iterator iter = ImageIO.getImageReadersByMIMEType(mimeType);
return iter.hasNext();
}
// Returns true if the specified mime type can be written
public static boolean canWriteMimeType(String mimeType) {
Iterator iter = ImageIO.getImageWritersByMIMEType(mimeType);
return iter.hasNext();
}
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<b>Related Examples</b></font></td>
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e694. <a class="eglink" href="BasicImageRead.html?l=rel">
Reading an Image from a File, InputStream, or URL
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e695. <a class="eglink" href="Graphic2File.html?l=rel">
Saving a Generated Graphic to a PNG or JPEG File
</a>
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e696. <a class="eglink" href="GetFormats.html?l=rel">
Listing the Image Formats That Can Be Read and Written
</a>
<br>
e698. <a class="eglink" href="DiscType.html?l=rel">
Determining the Format of an Image in a File
</a>
<br>
e699. <a class="eglink" href="JpegWrite.html?l=rel">
Compressing a JPEG File
</a>
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