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.
Asked
Active
Viewed 1.8k times
3 Answers
22
File file = new File("newname.ext");
if (!file.exists()) {
InputStream link = (getClass().getResourceAsStream("/path/resources/filename.ext"));
Files.copy(link, file.getAbsoluteFile().toPath());
}
-
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
10
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
- 79
- 7
Dave Newton
- 158,873
- 26
- 254
- 302
-
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
-
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
0
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)?
