CODEWITHSUNDEEP
java
Phoenix852
Phoenix852

Reputation: 11

Get a file from jar using index

I am trying to access a file using java.io.File from the running jar using index. I mean, like creating the array of the files in that folder and then get a file by its index.

Upvotes: 1

Views: 141

Answers (1)

Gopinath
Gopinath

Reputation: 4937

jar tf file.jar command can be used to list down contents of jar file.

An example of jar tf command utitlity:

> jar tf demo-1.0.0.jar

META-INF/
META-INF/MANIFEST.MF
org/
org/springframework/
org/springframework/boot/
org/springframework/boot/loader/
...
org/springframework/boot/loader/jar/
org/springframework/boot/loader/jar/JarURL

The same result can be obtained programmatically also, by using the java.jar.Jarfile class

Here is an example of programmatic lookup of contents of jar file:

// File name: JarLs.java
// This program lists down all the contents of a .jar file

import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.Enumeration;

public class JarLs {
    public static void main(String[] args) throws Exception {
        JarFile jarFile = new JarFile("D:/test/demo-1.0.0.jar");
        Enumeration<JarEntry> jarEntries = jarFile.entries();
        while (jarEntries.hasMoreElements()) {
            System.out.println(jarEntries.nextElement().getName());
        }
   }
}

Output:

> javac JarLs.java
> java JarLs

META-INF/
META-INF/MANIFEST.MF
org/
org/springframework/
org/springframework/boot/
org/springframework/boot/loader/
org/springframework/boot/loader/archive/
org/springframework/boot/loader/archive/ExplodedArchive$FileEntry.class
org/springframework/boot/loader/WarLauncher.class
...
...
BOOT-INF/
BOOT-INF/classes/
BOOT-INF/classes/com/
...
...
BOOT-INF/classes/com/demo/controller/WebTrafficController.class
BOOT-INF/classes/com/demo/SpringBootWebApplication.class

More information:

https://docs.oracle.com/javase/tutorial/deployment/jar/view.html

http://www.devx.com/tips/java/reading-contents-of-a-jar-file-using-java.-170629013043.html

Upvotes: 1

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