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java zip filesystem reading zip entries

SO, from what I've gathered, one is supposed to be able to create a filesystem from a zip from java 7 and beyond. I'm trying this, the ultimate goal is to use the File object and access these files, just as if I accessed an unzipped file.
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.*;
import java.util.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainZipTest {
public static void main(String[] args) throws IOException, URISyntaxException {
Map<String, String> env = new HashMap<>();
env.put("read", "true");
File file = new File("C:/pathtoazip/data.zip");
URI uri = file.toURI();
String path = "jar:" + uri;
FileSystem fs = FileSystems.newFileSystem(URI.create(path), env);
for (Path p : fs.getRootDirectories()) {
System.out.println("root" + p);
//says "/"
System.out.println(new File(p.toString()).exists());
for (File f : new File(p.toString()).listFiles())
System.out.println(f.getAbsolutePath());
//lists the contents of my c drive!
}
System.out.println(new File("somefile.txt").exists());
System.out.println(fs.getPath("somefile.txt").toFile().exists());
System.out.println(new File("/somefile.txt").exists());
System.out.println(fs.getPath("/somefile.txt").toFile().exists());
}
}
it all prints "false". What am I doing wrong here? Or am I wrong in my assumption that I can access these files through the File object? If so, how does one access them?

Path was introduced as generalization of File (disk file). A Path can be inside a zip file, an URL, and more.
You can use Files with Path for similar File functionality.
for (Path p : fs.getRootDirectories()) {
System.out.println("root: " + p);
System.out.println(Files.exists(p));
Files.list(p).forEach(f -> System.out.println(f.toAbsolutePath()));
}
Note that a Path, like from a zip will maintain its actual file system view (fs, the zip).
So avoid File.

How to zip a byte array using ZipFileSystem

How to create a zip file with a byte array using ZipFileSystem ?
The example in the Zip File System Provider shows how to zip an existing one, but I don't seem to find a way to create one from in memory byte array.

I didn't realize I was using the same value for the target zip file and the file inside the zip file.
Modifying the original example I have this working:
import java.util.*;
import java.net.URI;
import java.nio.file.Path;
import java.nio.file.*;
public class ZipFSPUser {
public static void main(String [] args) throws Throwable {
Map<String, String> env = new HashMap<>();
env.put("create", "true");
// locate file system by using the syntax
// defined in java.net.JarURLConnection
URI uri = URI.create("jar:file:/codeSamples/zipfs/zipfstest.zip");
try (FileSystem zipfs = FileSystems.newFileSystem(uri, env)) {
Path pathInZipfile = zipfs.getPath("/SomeTextFile.txt");
// copy a file into the zip file
Files.write(pathInZipfile, new byte[]{'h', 'i'} );
}
}
}
Now the /codeSamples/zipfs/zipfstest.zip file is created with /SomeTextFile.txt inside and when I unzip it the content is indeed hi

Create a new file in .zip folder using Scala

I have a requirement where I have to create 1 xml file inside my .zip folder.
Can you please let me know how can I achieve this using java/scala?
Also let me know can I directly update .zip folder Array[Byte] and add extra Array[Byte] for my new xml file ?

If you are using Java 7 and later, then you should use Zip File System
The following code sample shows how to create a zip file system and
copy a file to the new zip file system.
import java.util.*;
import java.net.URI;
import java.nio.file.Path;
import java.nio.file.*;
public class ZipFSPUser {
public static void main(String [] args) throws Throwable {
Map<String, String> env = new HashMap<>();
env.put("create", "true");
// locate file system by using the syntax
// defined in java.net.JarURLConnection
URI uri = URI.create("jar:file:/codeSamples/zipfs/zipfstest.zip");
try (FileSystem zipfs = FileSystems.newFileSystem(uri, env)) {
Path externalTxtFile = Paths.get("/codeSamples/zipfs/SomeTextFile.txt");
Path pathInZipfile = zipfs.getPath("/SomeTextFile.txt");
// copy a file into the zip file
Files.copy( externalTxtFile,pathInZipfile,
StandardCopyOption.REPLACE_EXISTING );
}
}
}
This post could help you: Appending files to a zip file with Java

Moving large files in java

I have to move files from one directory to other directory.
Am using property file. So the source and destination path is stored in property file.
Am haivng property reader class also.
In my source directory am having lots of files. One file should move to other directory if its complete the operation.
File size is more than 500MB.
import java.io.File;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import static java.nio.file.StandardCopyOption.*;
public class Main1
{
public static String primarydir="";
public static String secondarydir="";
public static void main(String[] argv)
throws Exception
{
primarydir=PropertyReader.getProperty("primarydir");
System.out.println(primarydir);
secondarydir=PropertyReader.getProperty("secondarydir");
File dir = new File(primarydir);
secondarydir=PropertyReader.getProperty("secondarydir");
String[] children = dir.list();
if (children == null)
{
System.out.println("does not exist or is not a directory");
}
else
{
for (int i = 0; i < children.length; i++)
{
String filename = children[i];
System.out.println(filename);
try
{
File oldFile = new File(primarydir,children[i]);
System.out.println( "Before Moving"+oldFile.getName());
if (oldFile.renameTo(new File(secondarydir+oldFile.getName())))
{
System.out.println("The file was moved successfully to the new folder");
}
else
{
System.out.println("The File was not moved.");
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
System.out.println("ok");
}
}
}
My code is not moving the file into the correct path.
This is my property file
primarydir=C:/Desktop/A
secondarydir=D:/B
enter code here
Files should be in B drive. How to do? Any one can help me..!!

Change this:
oldFile.renameTo(new File(secondarydir+oldFile.getName()))
To this:
oldFile.renameTo(new File(secondarydir, oldFile.getName()))
It's best not to use string concatenation to join path segments, as the proper way to do it may be platform-dependent.
Edit: If you can use JDK 1.7 APIs, you can use Files.move() instead of File.renameTo()

Code - a java method:
/**
* copy by transfer, use this for cross partition copy,
* #param sFile source file,
* #param tFile target file,
* #throws IOException
*/
public static void copyByTransfer(File sFile, File tFile) throws IOException {
FileInputStream fInput = new FileInputStream(sFile);
FileOutputStream fOutput = new FileOutputStream(tFile);
FileChannel fReadChannel = fInput.getChannel();
FileChannel fWriteChannel = fOutput.getChannel();
fReadChannel.transferTo(0, fReadChannel.size(), fWriteChannel);
fReadChannel.close();
fWriteChannel.close();
fInput.close();
fOutput.close();
}
The method use nio, it make use os underling operation to improve performance.
Here is the import code:
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
If you are in eclipse, just use ctrl + shift + o.

Get file owner metadata information with java

I am trying to retrieve the owner of a file, using this code:
Path file = Paths.get( fileToExtract.getAbsolutePath() );
PosixFileAttributes attr = Files.readAttributes(file, PosixFileAttributes.class); //line that throws exception
System.out.println(attr.owner.getName());
taken from oracle's page (http://docs.oracle.com/javase/tutorial/essential/io/fileAttr.html)
but i always get a UnsupportedOperationException at the line i indicate above.
java.lang.UnsupportedOperationException
at sun.nio.fs.WindowsFileSystemProvider.readAttributes(WindowsFileSystemProvider.java:192)
at java.nio.file.Files.readAttributes(Files.java:1684)
I think that 'readAttributes' method is abstract and this cause the exception, but (if this is true) i don't know how to implement this method in order to give me the file attributes.
Does anyone know how to implement this method, or an alternative method (that is tested) to get the file owner?

Try this - works also on Windows
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileOwnerAttributeView;
import java.nio.file.attribute.UserPrincipal;
public class FileOwner {
public static void main(String[] args) throws IOException {
Path path = Paths.get("/tmp");
FileOwnerAttributeView ownerAttributeView = Files.getFileAttributeView(path, FileOwnerAttributeView.class);
UserPrincipal owner = ownerAttributeView.getOwner();
System.out.println("owner: " + owner.getName());
}
}

Use BasicFileAttributes instead.
BasicFileAttributes attr = Files.readAttributes(file, BasicFileAttributes.class);
Posix file attributes are not supported in Windows.

Here is is a sample for files permissions on UNIX/Linux platforms
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFileAttributes;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
import java.util.Set;
class A {
public static void main(String[] args) throws Exception
{
//Make sure file exists e.g. Unix path structure
Path p = Paths.get("/a/b/Log.txt");
PosixFileAttributes posix = Files.readAttributes(p,
PosixFileAttributes.class);
//Set Permissions if needs be for the file Log.txt
Set<PosixFilePermission> perms =
PosixFilePermissions.fromString("rw-r--r--");
Files.setPosixFilePermissions(p, perms);
//Output the various attributes of the file named Log.txt
System.out.println(posix.group());
System.out.println(posix.permissions());
System.out.println(posix.owner());
}
}