Are there any built-in methods I can use to allow users to extract a file from the currently running JAR and save it on their disk?
Thanks in advance.
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File file = new File("newname.ext");
if (!file.exists()) {
InputStream link = (getClass().getResourceAsStream("/path/resources/filename.ext"));
Files.copy(link, file.getAbsoluteFile().toPath());
}
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Note that some of Files.copy implementation (java.nio.file.Files) does not close the input stream -> possible memory leak. – Vity Jan 25 '18 at 07:24
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Use getResourceAsStream (docs), you can do whatever you want with it after that.
For a two-liner you could use one of the Commons IO copy methods.
milchreis
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Dave Newton
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getResourceAsStream will give you access to any matching resource on the class path and not only a file withing the "currently running JAR", assuming that that is a JAR file executed with "java -jar
". – jarnbjo Jul 13 '12 at 14:28 -
@jarnbjo Yep. And if the resource isn't properly packaged, that's *possibly* an issue, but given the question, I think the issue is much broader than needing it to come *specifically* from the "running jar", to the exclusion of all other resources packaged exactly the same. – Dave Newton Jul 13 '12 at 14:32
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Note that you may want to specify an *absolute* path to the file in the jar. And then *any* class can be used. Example: InputStream is = Object.class.getResource("/" + filename).openStream(); – Per Lindberg Oct 26 '16 at 14:23
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I am not sure whether you will get know from which jar your class is getting executed but you can try this to extract resources from jar : How to write a Java program which can extract a JAR file and store its data in specified directory (location)?
