Read Content from Files which are inside Zip file

Solution 1:

If you're wondering how to get the file content from each ZipEntry it's actually quite simple. Here's a sample code:

public static void main(String[] args) throws IOException {
    ZipFile zipFile = new ZipFile("C:/test.zip");

    Enumeration<? extends ZipEntry> entries = zipFile.entries();

    while(entries.hasMoreElements()){
        ZipEntry entry = entries.nextElement();
        InputStream stream = zipFile.getInputStream(entry);
    }
}

Once you have the InputStream you can read it however you want.

Solution 2:

As of Java 7, the NIO Api provides a better and more generic way of accessing the contents of Zip or Jar files. Actually, it is now a unified API which allows you to treat Zip files exactly like normal files.

In order to extract all of the files contained inside of a zip file in this API, you'd do this:

In Java 8:

private void extractAll(URI fromZip, Path toDirectory) throws IOException{
    FileSystems.newFileSystem(fromZip, Collections.emptyMap())
            .getRootDirectories()
            .forEach(root -> {
                // in a full implementation, you'd have to
                // handle directories 
                Files.walk(root).forEach(path -> Files.copy(path, toDirectory));
            });
}

In java 7:

private void extractAll(URI fromZip, Path toDirectory) throws IOException{
    FileSystem zipFs = FileSystems.newFileSystem(fromZip, Collections.emptyMap());

    for(Path root : zipFs.getRootDirectories()) {
        Files.walkFileTree(root, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) 
                    throws IOException {
                // You can do anything you want with the path here
                Files.copy(file, toDirectory);
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) 
                    throws IOException {
                // In a full implementation, you'd need to create each 
                // sub-directory of the destination directory before 
                // copying files into it
                return super.preVisitDirectory(dir, attrs);
            }
        });
    }
}

Solution 3:

Because of the condition in while, the loop might never break:

while (entry != null) {
  // If entry never becomes null here, loop will never break.
}

Instead of the null check there, you can try this:

ZipEntry entry = null;
while ((entry = zip.getNextEntry()) != null) {
  // Rest of your code
}

Solution 4:

Sample code you can use to let Tika take care of container files for you. http://wiki.apache.org/tika/RecursiveMetadata

Form what I can tell, the accepted solution will not work for cases where there are nested zip files. Tika, however will take care of such situations as well.