Get file date and time : File Utilities « File « Java Tutorial





import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;

/*
 * IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
 *
 * http://izpack.org/
 * http://izpack.codehaus.org/
 *
 * Copyright 2005 Marc Eppelmann
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * Provides general global file utility methods
 *
 * @author marc.eppelmann
 */
class FileUtil
{
    //~ Constructors ***********************************************************************

    /**
     * Creates a new FileUtil object.
     */
    public FileUtil()
    {
    }

    //~ Methods ****************************************************************************

    /**
     * Gets the content from a File as StringArray List.
     *
     * @param fileName A file to read from.
     * @return List of individual line of the specified file. List may be empty but not
     *         null.
     * @throws IOException
     */
    public static ArrayList getFileContent(String fileName)
            throws IOException
    {
        ArrayList result = new ArrayList();

        File aFile = new File(fileName);

        if (!aFile.isFile())
        {
            //throw new IOException( fileName + " is not a regular File" );
            return result; // None
        }

        BufferedReader reader = null;

        try
        {
            reader = new BufferedReader(new FileReader(aFile));
        }
        catch (FileNotFoundException e1)
        {
            // TODO handle Exception
            e1.printStackTrace();

            return result;
        }

        String aLine = null;

        while ((aLine = reader.readLine()) != null)
        {
            result.add(aLine + "\n");
        }

        reader.close();

        return result;
    }

    /**
     * Searches case sensitively, and returns true if the given SearchString occurs in the
     * first File with the given Filename.
     *
     * @param aFileName     A files name
     * @param aSearchString the string search for
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString)
    {
        return (fileContains(aFileName, aSearchString, false));
    }

    /**
     * Tests if the given File contains the given Search String
     *
     * @param aFileName             A files name
     * @param aSearchString         the String to search for
     * @param caseInSensitiveSearch If false the Search is casesensitive
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString,
                                       boolean caseInSensitiveSearch)
    {
        boolean result = false;

        String searchString = caseInSensitiveSearch
                ? aSearchString.toLowerCase() : aSearchString;

        ArrayList fileContent = new ArrayList();

        try
        {
            fileContent = getFileContent(aFileName);
        }
        catch (IOException e)
        {
            // TODO handle Exception
            e.printStackTrace();
        }

        Iterator linesIter = fileContent.iterator();

        while (linesIter.hasNext())
        {
            String currentline = (String) linesIter.next();

            if (caseInSensitiveSearch)
            {
                currentline = currentline.toLowerCase();
            }

            if (currentline.indexOf(searchString) > -1)
            {
                result = true;

                break;
            }
        }

        return result;
    }

    /**
     * Gets file date and time.
     *
     * @param url The URL of the file for which date and time will be returned.
     * @return Returns long value which is the date and time of the file. If any error
     *         occures returns -1 (=no file date and time available).
     */
    public static long getFileDateTime(URL url)
    {
        if (url == null)
        {
            return -1;
        }

        String fileName = url.getFile();
        if (fileName.charAt(0) == '/' || fileName.charAt(0) == '\\')
        {
            fileName = fileName.substring(1, fileName.length());
        }

        try
        {
            File file = new File(fileName);
            // File name must be a file or a directory.
            if (!file.isDirectory() && !file.isFile())
            {
                return -1;
            }

            return file.lastModified();
        }
        catch (java.lang.Exception e)
        {   // Trap all Exception based exceptions and return -1.
            return -1;
        }
    }

    public static String[] getFileNames(String dirPath) throws Exception
    {
        return getFileNames(dirPath, null);
    }

    public static String[] getFileNames(String dirPath, FilenameFilter fileNameFilter) throws Exception
    {
        String fileNames[] = null;
        File dir = new File(dirPath);
        if (dir.isDirectory())
        {
            if (fileNameFilter != null)
            {
                fileNames = dir.list(fileNameFilter);
            }
            else
            {
                fileNames = dir.list();
            }
        }
        return fileNames;
    }

    /**
     * Test main
     *
     * @param args
     */
    public static void main(String[] args)
    {
    }
}










11.55.File Utilities
11.55.1.Ensuring a File Exists
11.55.2.Avoiding Overwriting a File
11.55.3.Copying Files using FileChannel
11.55.4.Format Size
11.55.5.Move File
11.55.6.Compare binary files
11.55.7.Get file date and time
11.55.8.Rename To Temporary Name
11.55.9.Return readable file size with selected value measure
11.55.10.Utility class for synchronizing files/directories
11.55.11.Count files in a directory (including files in all subdirectories)
11.55.12.Extract File Extension
11.55.13.Strip File Extension
11.55.14.Remove File Name Suffix
11.55.15.Get File Name Suffix