Unzips the specified zip file to the specified destination directory.

Description

Demo Code


//package com.java2s;

import java.io.IOException;
import java.net.URI;

import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.attribute.BasicFileAttributes;

import java.util.HashMap;
import java.util.Map;

public class Main {
    /**/*from www  .  ja  va2 s.co  m*/
     * Unzips the specified zip file to the specified destination directory. Replaces any files in
     * the destination, if they already exist.
     * 
     * @param zipFilename the name of the zip file to extract
     * @param destFilename the directory to unzip to
     * @throws IOException
     */
    public static void unzip(String zipFilename, String destDirname)
            throws IOException {
        final Path destDir = Paths.get(destDirname);
        //if the destination doesn't exist, create it
        if (Files.notExists(destDir)) {
            System.out.println(destDir + " does not exist. Creating...");
            Files.createDirectories(destDir);
        }

        try (FileSystem zipFileSystem = createZipFileSystem(zipFilename,
                false)) {
            final Path root = zipFileSystem.getPath("/");

            //walk the zip file tree and copy files to the destination
            Files.walkFileTree(root, new SimpleFileVisitor<Path>() {
                @Override
                public FileVisitResult visitFile(Path file,
                        BasicFileAttributes attrs) throws IOException {
                    final Path destFile = Paths.get(destDir.toString(),
                            file.toString());
                    System.out.printf("Extracting file %s to %s\n", file,
                            destFile);
                    Files.copy(file, destFile,
                            StandardCopyOption.REPLACE_EXISTING);
                    return FileVisitResult.CONTINUE;
                }

                @Override
                public FileVisitResult preVisitDirectory(Path dir,
                        BasicFileAttributes attrs) throws IOException {
                    final Path dirToCreate = Paths.get(destDir.toString(),
                            dir.toString());
                    if (Files.notExists(dirToCreate)) {
                        System.out.printf("Creating directory %s\n",
                                dirToCreate);
                        Files.createDirectory(dirToCreate);
                    }
                    return FileVisitResult.CONTINUE;
                }
            });
        }
    }

    /**
     * Returns a zip file system
     * 
     * @param zipFilename to construct the file system from
     * @param create <code>true</code> if the zip file should be created
     * @return a zip file system
     * @throws IOException
     */
    public static FileSystem createZipFileSystem(String zipFilename,
            boolean create) throws IOException {
        final Path path = Paths.get(zipFilename);
        final URI uri = URI.create("jar:file:" + path.toUri().getPath());
        final Map<String, String> env = new HashMap<>();
        if (create) {
            env.put("create", "true");
        }
        return FileSystems.newFileSystem(uri, env);
    }

    /**
     * Creates/updates a zip file.
     * 
     * @param zipFilename the name of the zip to create
     * @param filenames list of filename to add to the zip
     * @throws IOException
     */
    public static void create(String zipFilename, String... filenames)
            throws IOException {
        try (FileSystem zipFileSystem = createZipFileSystem(zipFilename,
                true)) {
            final Path root = zipFileSystem.getPath("/");

            //iterate over the files we need to add
            for (String filename : filenames) {
                final Path src = Paths.get(filename);

                //add a file to the zip file system
                if (!Files.isDirectory(src)) {
                    final Path dest = zipFileSystem.getPath(
                            root.toString(), src.toString());
                    final Path parent = dest.getParent();
                    if (Files.notExists(parent)) {
                        System.out
                                .printf("Creating directory %s\n", parent);
                        Files.createDirectories(parent);
                    }
                    Files.copy(src, dest,
                            StandardCopyOption.REPLACE_EXISTING);
                } else {
                    //for directories, walk the file tree
                    Files.walkFileTree(src, new SimpleFileVisitor<Path>() {
                        @Override
                        public FileVisitResult visitFile(Path file,
                                BasicFileAttributes attrs)
                                throws IOException {
                            final Path dest = zipFileSystem.getPath(
                                    root.toString(), file.toString());
                            Files.copy(file, dest,
                                    StandardCopyOption.REPLACE_EXISTING);
                            return FileVisitResult.CONTINUE;
                        }

                        @Override
                        public FileVisitResult preVisitDirectory(Path dir,
                                BasicFileAttributes attrs)
                                throws IOException {
                            final Path dirToCreate = zipFileSystem.getPath(
                                    root.toString(), dir.toString());
                            if (Files.notExists(dirToCreate)) {
                                System.out.printf(
                                        "Creating directory %s\n",
                                        dirToCreate);
                                Files.createDirectories(dirToCreate);
                            }
                            return FileVisitResult.CONTINUE;
                        }
                    });
                }
            }
        }
    }
}
Unzips the specified zip file to the specified destination directory. - Java File Path IO

Description

Demo Code

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