EN
Java - get file extension
6 points
In this article, we would like to show you how to get a file extension in Java.
Practical example:
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import java.io.*;2
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public class Program {4
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public static void main(String[] args) {6
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// Common:8
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System.out.println(PathUtils.getExtension("image.png")); // png10
System.out.println(PathUtils.getExtension("audio.mp3")); // mp311
System.out.println(PathUtils.getExtension("document.pdf")); // pdf12
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System.out.println(PathUtils.getExtension(".")); //14
System.out.println(PathUtils.getExtension("..")); //15
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System.out.println(PathUtils.getExtension(".htaccess")); //17
System.out.println(PathUtils.getExtension(".tar.gz")); // gz18
System.out.println(PathUtils.getExtension("makefile")); //19
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// Unix/Linux/macOS:21
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System.out.println(PathUtils.getExtension("/path/.htaccess")); //23
System.out.println(PathUtils.getExtension("/path/.tar.gz")); // gz24
System.out.println(PathUtils.getExtension("/path/makefile")); //25
System.out.println(PathUtils.getExtension("/path/example.pdf")); // pdf26
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// Windows:28
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System.out.println(PathUtils.getExtension("C:\\path\\.htaccess")); //30
System.out.println(PathUtils.getExtension("C:\\path\\.tar.gz")); // gz31
System.out.println(PathUtils.getExtension("C:\\path\\makefile")); //32
System.out.println(PathUtils.getExtension("C:\\path\\example.pdf")); // pdf33
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// Also:35
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System.out.println(PathUtils.getExtension("C:.htaccess")); //37
System.out.println(PathUtils.getExtension("C:.tar.gz")); // gz38
System.out.println(PathUtils.getExtension("C:makefile")); //39
System.out.println(PathUtils.getExtension("C:example.pdf")); // pdf40
}41
}Output:
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png2
mp33
pdf4
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6
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gz8
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gz11
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pdf13
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gz15
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pdf17
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gz19
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pdf
PathUtils.java file:
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public final class PathUtils {2
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public static String getExtension(String path) {4
int length = path.length();5
for (int i = length - 1; i > -1; --i) {6
char value = path.charAt(i);7
if (value == '.') {8
if (i > 1) {9
value = path.charAt(i - 1);10
if (value == '/' || value == '\\' || value == ':') {11
return "";12
}13
return path.substring(i + 1);14
}15
return "";16
}17
if (value == '/' || value == '\\' || value == ':') {18
return "";19
}20
}21
return "";22
}23
}
