fileutils.java

java上传文件的一个例子。使用了apache的第三方开源组件。

     * @return true if the content of the files are equal or they both don't
     * exist, false otherwise
     * @throws IOException in case of an I/O error
     */
    public static boolean contentEquals(File file1, File file2) throws IOException {
        boolean file1Exists = file1.exists();
        if (file1Exists != file2.exists()) {
            return false;
        }

        if (!file1Exists) {
            // two not existing files are equal
            return true;
        }

        if (file1.isDirectory() || file2.isDirectory()) {
            // don't want to compare directory contents
            throw new IOException("Can't compare directories, only files");
        }

        if (file1.length() != file2.length()) {
            // lengths differ, cannot be equal
            return false;
        }

        if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
            // same file
            return true;
        }

        InputStream input1 = null;
        InputStream input2 = null;
        try {
            input1 = new FileInputStream(file1);
            input2 = new FileInputStream(file2);
            return IOUtils.contentEquals(input1, input2);

        } finally {
            IOUtils.closeQuietly(input1);
            IOUtils.closeQuietly(input2);
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Convert from a <code>URL</code> to a <code>File</code>.
     * <p>
     * From version 1.1 this method will decode the URL.
     * Syntax such as <code>file:///my%20docs/file.txt</code> will be
     * correctly decoded to <code>/my docs/file.txt</code>.
     *
     * @param url  the file URL to convert, null returns null
     * @return the equivalent <code>File</code> object, or <code>null</code>
     *  if the URL's protocol is not <code>file</code>
     * @throws IllegalArgumentException if the file is incorrectly encoded
     */
    public static File toFile(URL url) {
        if (url == null || !url.getProtocol().equals("file")) {
            return null;
        } else {
            String filename = url.getFile().replace('/', File.separatorChar);
            int pos =0;
            while ((pos = filename.indexOf('%', pos)) >= 0) {
                if (pos + 2 < filename.length()) {
                    String hexStr = filename.substring(pos + 1, pos + 3);
                    char ch = (char) Integer.parseInt(hexStr, 16);
                    filename = filename.substring(0, pos) + ch + filename.substring(pos + 3);
                }
            }
            return new File(filename);
        }
    }

    /**
     * Converts each of an array of <code>URL</code> to a <code>File</code>.
     * <p>
     * Returns an array of the same size as the input.
     * If the input is null, an empty array is returned.
     * If the input contains null, the output array contains null at the same
     * index.
     * <p>
     * This method will decode the URL.
     * Syntax such as <code>file:///my%20docs/file.txt</code> will be
     * correctly decoded to <code>/my docs/file.txt</code>.
     *
     * @param urls  the file URLs to convert, null returns empty array
     * @return a non-null array of Files matching the input, with a null item
     *  if there was a null at that index in the input array
     * @throws IllegalArgumentException if any file is not a URL file
     * @throws IllegalArgumentException if any file is incorrectly encoded
     * @since Commons IO 1.1
     */
    public static File[] toFiles(URL[] urls) {
        if (urls == null || urls.length == 0) {
            return EMPTY_FILE_ARRAY;
        }
        File[] files = new File[urls.length];
        for (int i = 0; i < urls.length; i++) {
            URL url = urls[i];
            if (url != null) {
                if (url.getProtocol().equals("file") == false) {
                    throw new IllegalArgumentException(
                            "URL could not be converted to a File: " + url);
                }
                files[i] = toFile(url);
            }
        }
        return files;
    }

    /**
     * Converts each of an array of <code>File</code> to a <code>URL</code>.
     * <p>
     * Returns an array of the same size as the input.
     *
     * @param files  the files to convert
     * @return an array of URLs matching the input
     * @throws IOException if a file cannot be converted
     */
    public static URL[] toURLs(File[] files) throws IOException {
        URL[] urls = new URL[files.length];

        for (int i = 0; i < urls.length; i++) {
            urls[i] = files[i].toURL();
        }

        return urls;
    }

    //-----------------------------------------------------------------------
    /**
     * Copies a file to a directory preserving the file date.
     * <p>
     * This method copies the contents of the specified source file
     * to a file of the same name in the specified destination directory.
     * The destination directory is created if it does not exist.
     * If the destination file exists, then this method will overwrite it.
     *
     * @param srcFile  an existing file to copy, must not be null
     * @param destDir  the directory to place the copy in, must not be null
     *
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFile(File, File, boolean)
     */
    public static void copyFileToDirectory(File srcFile, File destDir) throws IOException {
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (destDir.exists() && destDir.isDirectory() == false) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        copyFile(srcFile, new File(destDir, srcFile.getName()), true);
    }

    /**
     * Copies a file to a new location preserving the file date.
     * <p>
     * This method copies the contents of the specified source file to the
     * specified destination file. The directory holding the destination file is
     * created if it does not exist. If the destination file exists, then this
     * method will overwrite it.
     * 
     * @param srcFile  an existing file to copy, must not be null
     * @param destFile  the new file, must not be null
     * 
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFileToDirectory
     */
    public static void copyFile(File srcFile, File destFile) throws IOException {
        copyFile(srcFile, destFile, true);
    }

    /**
     * Copies a file to a new location.
     * <p>
     * This method copies the contents of the specified source file
     * to the specified destination file.
     * The directory holding the destination file is created if it does not exist.
     * If the destination file exists, then this method will overwrite it.
     *
     * @param srcFile  an existing file to copy, must not be null
     * @param destFile  the new file, must not be null
     * @param preserveFileDate  true if the file date of the copy
     *  should be the same as the original
     *
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @see #copyFileToDirectory
     */
    public static void copyFile(File srcFile, File destFile,
            boolean preserveFileDate) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (srcFile.exists() == false) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' exists but is a directory");
        }
        if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
            throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
        }
        if (destFile.getParentFile() != null && destFile.getParentFile().exists() == false) {
            if (destFile.getParentFile().mkdirs() == false) {
                throw new IOException("Destination '" + destFile + "' directory cannot be created");
            }
        }
        if (destFile.exists() && destFile.canWrite() == false) {
            throw new IOException("Destination '" + destFile + "' exists but is read-only");
        }
        doCopyFile(srcFile, destFile, preserveFileDate);
    }

    /**
     * Internal copy file method.
     * 
     * @param srcFile  the validated source file, not null
     * @param destFile  the validated destination file, not null
     * @param preserveFileDate  whether to preserve the file date
     * @throws IOException if an error occurs
     */
    private static void doCopyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (destFile.exists() && destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' exists but is a directory");
        }

        FileInputStream input = new FileInputStream(srcFile);
        try {
            FileOutputStream output = new FileOutputStream(destFile);
            try {
                IOUtils.copy(input, output);
            } finally {
                IOUtils.closeQuietly(output);
            }
        } finally {
            IOUtils.closeQuietly(input);
        }

        if (srcFile.length() != destFile.length()) {
            throw new IOException("Failed to copy full contents from '" +
                    srcFile + "' to '" + destFile + "'");
        }
        if (preserveFileDate) {
            destFile.setLastModified(srcFile.lastModified());
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Copies a directory to within another directory preserving the file dates.
     * <p>
     * This method copies the source directory and all its contents to a
     * directory of the same name in the specified destination directory.
     * <p>
     * The destination directory is created if it does not exist.
     * If the destination directory did exist, then this method merges
     * the source with the destination, with the source taking precedence.
     *
     * @param srcDir  an existing directory to copy, must not be null
     * @param destDir  the directory to place the copy in, must not be null
     *
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @since Commons IO 1.2
     */
    public static void copyDirectoryToDirectory(File srcDir, File destDir) throws IOException {
        if (srcDir == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (srcDir.exists() && srcDir.isDirectory() == false) {
            throw new IllegalArgumentException("Source '" + destDir + "' is not a directory");
        }
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (destDir.exists() && destDir.isDirectory() == false) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        copyDirectory(srcDir, new File(destDir, srcDir.getName()), true);
    }

    /**
     * Copies a whole directory to a new location preserving the file dates.
     * <p>
     * This method copies the specified directory and all its child
     * directories and files to the specified destination.
     * The destination is the new location and name of the directory.
     * <p>
     * The destination directory is created if it does not exist.
     * If the destination directory did exist, then this method merges
     * the source with the destination, with the source taking precedence.
     *
     * @param srcDir  an existing directory to copy, must not be null
     * @param destDir  the new directory, must not be null
     *
     * @throws NullPointerException if source or destination is null
     * @throws IOException if source or destination is invalid
     * @throws IOException if an IO error occurs during copying
     * @since Commons IO 1.1
     */
    public static void copyDirectory(File srcDir, File destDir) throws IOException {
        copyDirectory(srcDir, destDir, true);
    }

    /**
     * Copies a whole directory to a new location.
     * <p>
     * This method copies the contents of the specified source directory
     * to within the specified destination directory.
     * <p>
     * The destination directory is created if it does not exist.
     * If the destination directory did exist, then this method merges
     * the source with the destination, with the source taking precedence.
     *