JAVA GET FILE PATH WITHOUT NAME HOW TO
JAVA GET FILE PATH WITHOUT NAME CODE

* Type of file for which name was provided. * using JDK's URLConnection.getContentType().

JAVA GET FILE PATH WITHOUT NAME CODE

The first is URLConnection.getContentType(), a method that 'returns the value of the content-type header field.' Use of this instance method is demonstrated in the next code listing and the output from running that code against the common test files is shown after the code listing. I will be covering three methods in URLConnection that support file type detection. We see also that, like the previously discussed approach, this approach in some cases uses the file's extension to determine the file type and so incorrectly reports the file's actual file type when that type is different than what its extension conventionally implies. This output indicates that the MimetypesFileTypeMap approach returns the MIME type of application/octet-stream for several files including the XML files and the text files without a. The next screen snapshot demonstrates the output from running this example against the set of test files. Return fileTypeMap.getContentType(fileName) Public String identifyFileTypeUsingMimetypesFileTypeMap(final String fileName)įinal MimetypesFileTypeMap fileTypeMap = new MimetypesFileTypeMap()

JAVA GET FILE PATH WITHOUT NAME HOW TO

* for details on how to configure mapping of file types or extensions. * See Javadoc documentation for MimetypesFileTypeMap class * Identify file type of file with provided name using The next code listing demonstrates use of. My example uses the ones that come out-of-the-box with my JDK 8 installation. mime.types format.' The class's Javadoc explains where in a given system the class looks for MIME types file entries. The class MimetypesFileTypeMap was introduced with Java SE 6 to provide 'data typing of files via their file extension' using 'the. MimetypesFileTypeMap.getContentType(String) For example, all three files with names starting with 'dustin' are really the same single-sentence text file, but Files.probeContentType(Path) states that they are each a different type and the listed types are tightly correlated with the different file extensions for essentially the same text file. The files with no extensions show 'null' for file type and the other listed file types match the files' extensions rather than their actual content. The screen snapshot indicates that the default behavior for Files.probeContentType(Path) on my JVM seems to be tightly coupled to the file extension. When the above Files.probeContentType(Path)-based approach is executed against the set of files previously defined, the output appears as shown in the next screen snapshot. 'ERROR: Unable to determine file type for ' + fileName Public String identifyFileTypeUsingFilesProbeContentType(final String fileName)įileType = Files.probeContentType(file.toPath()) * String representing identified type of file with provided name. * fileName Name of file whose type is desired.

* using JDK 7's Files.probeContentType(Path). * Identify file type of file with provided path and name

The class provides the method probeContentType(Path) that 'probes the content type of a file' through use of 'the installed FileTypeDetector implementations' (the Javadoc also notes that 'a given invocation of the Java virtual machine maintains a system-wide list of file type detectors'). Java SE 7 introduced the highly utilitarian Files class and that class's Javadoc succinctly describes its use: 'This class consists exclusively of static methods that operate on files, directories, or other types of files' and, 'in most cases, the methods defined here will delegate to the associated file system provider to perform the file operations.'

Before covering these approaches and demonstrating the type each approach detects, I list the files under test and what they are named and what they really are. The screen snapshots shown in this post are of each listed code snippet run against certain subject files created to test the different implementations of file type detection in Java. Some of the approaches are configurable, but all examples shown here use 'default' mappings as provided out-of-the-box unless otherwise stated. Each approach is briefly described, illustrated with a code listing, and then associated with output that demonstrates how different common files are typed based on extensions. Several approaches to identifying file types in Java are demonstrated in this post. This post looks at some of the most commonly available implementations of file type detection in Java. There are several implementations available in Java for detecting file types and most of them are largely or solely based on files' extensions. Programmatically determining the type of a file can be surprisingly tricky and there have been many content-based file identification approaches proposed and implemented.

Java get file path without name