Problem
If I have a file upload function in my web application, this function need to check the file which upload by user is image file or not. How to do it?
How-To
You can make good use of Apache Tika to fulfill this requirement.
Add dependency in your pom.xml
<dependency>
<groupId>org.apache.tika</groupId>
<artifactId>tika-core</artifactId>
<version>1.14</version>
<scope>compile</scope>
</dependency>
Sample code is as follow:
package albert.practice.file;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.io.FileUtils;
import org.apache.tika.Tika;
import lombok.extern.slf4j.Slf4j;
@Slf4j
public class FileContentTypeUtils {
private static List<String> imageMediaTypes = new ArrayList<>();
private static void setImageMediaTypes() {
// http://www.fileformat.info/info/mimetype/image/index.htm
imageMediaTypes = Arrays.asList("image/cgm", "image/fits",
"image/g3fax", "image/gif", "image/ief", "image/jp2",
"image/jpeg", "image/jpm", "image/jpx", "image/naplps",
"image/png", "image/prs.btif", "image/prs.pti", "image/t38",
"image/tiff", "image/tiff-fx", "image/vnd.adobe.photoshop",
"image/vnd.cns.inf2", "image/vnd.djvu", "image/vnd.dwg",
"image/vnd.dxf", "image/vnd.fastbidsheet", "image/vnd.fpx",
"image/vnd.fst", "image/vnd.fujixerox.edmics-mmr",
"image/vnd.fujixerox.edmics-rlc",
"image/vnd.globalgraphics.pgb", "image/vnd.microsoft.icon",
"image/vnd.mix", "image/vnd.ms-modi", "image/vnd.net-fpx",
"image/vnd.sealed.png", "image/vnd.sealedmedia.softseal.gif",
"image/vnd.sealedmedia.softseal.jpg", "image/vnd.svf",
"image/vnd.wap.wbmp", "image/vnd.xiff");
}
public static Boolean isImage(String sourceFile) throws IOException {
setImageMediaTypes();
Boolean isImage = Boolean.FALSE;
File file = FileUtils.getFile(sourceFile);
Tika tika = new Tika();
try {
String mediaType = tika.detect(file);
isImage = imageMediaTypes.contains(mediaType);
} catch (IOException e) {
throw e;
}
return isImage;
}
}
Test code is the following:
package albert.practice.file;
import java.io.IOException;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
public class FileContentTypeUtilsTest extends FileContentTypeUtils {
private String imageFile;
private String pdfFile;
@Before
public void setup() {
imageFile = "/Users/albert/Dropbox/picture/panda.png";
pdfFile = "/Users/albert/Dropbox/test_測試.pdf";
}
@Test
public void testImageFile() throws IOException {
Assert.assertTrue(isImage(imageFile));
}
@Test
public void testPdfFile() throws IOException {
Assert.assertFalse(isImage(pdfFile));
}
}
Test results are shown bellow:
