edu.isi.webserver.FileUtil.java Source code

Introduction

Here is the source code for edu.isi.webserver.FileUtil.java

Source

/*******************************************************************************
 * Copyright 2012 University of Southern California
 * 
 * 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.
 * 
 * This code was developed by the Information Integration Group as part 
 * of the Karma project at the Information Sciences Institute of the 
 * University of Southern California.  For more information, publications, 
 * and related projects, please see: http://www.isi.edu/integration
 ******************************************************************************/
package edu.isi.webserver;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class FileUtil {
    private static String DESTINATION_DIR_PATH = "UserUploadedFiles/";
    private static Logger logger = LoggerFactory.getLogger(FileUtil.class);

    static public File downloadFileFromHTTPRequest(HttpServletRequest request) {
        // Download the file to the upload file folder
        File destinationDir = new File(DESTINATION_DIR_PATH);
        logger.info("File upload destination directory: " + destinationDir.getAbsolutePath());
        if (!destinationDir.isDirectory()) {
            destinationDir.mkdir();
        }

        DiskFileItemFactory fileItemFactory = new DiskFileItemFactory();

        // Set the size threshold, above which content will be stored on disk.
        fileItemFactory.setSizeThreshold(1 * 1024 * 1024); //1 MB

        //Set the temporary directory to store the uploaded files of size above threshold.
        fileItemFactory.setRepository(destinationDir);

        ServletFileUpload uploadHandler = new ServletFileUpload(fileItemFactory);

        File uploadedFile = null;
        try {
            // Parse the request
            @SuppressWarnings("rawtypes")
            List items = uploadHandler.parseRequest(request);
            @SuppressWarnings("rawtypes")
            Iterator itr = items.iterator();
            while (itr.hasNext()) {
                FileItem item = (FileItem) itr.next();

                // Ignore Form Fields.
                if (item.isFormField()) {
                    System.out.println(item.getFieldName());
                    System.out.println(item.getString());
                    // Do nothing
                } else {
                    //Handle Uploaded files. Write file to the ultimate location.
                    System.out.println("File field name: " + item.getFieldName());
                    uploadedFile = new File(destinationDir, item.getName());
                    item.write(uploadedFile);
                    System.out.println("File written to: " + uploadedFile.getAbsolutePath());
                }
            }
        } catch (FileUploadException ex) {
            logger.error("Error encountered while parsing the request", ex);
        } catch (Exception ex) {
            logger.error("Error encountered while uploading file", ex);
        }
        return uploadedFile;
    }

    public static void copyFiles(File destination, File source) throws FileNotFoundException, IOException {
        if (!destination.exists())
            destination.createNewFile();
        InputStream in = new FileInputStream(source);
        OutputStream out = new FileOutputStream(destination);

        byte[] buf = new byte[1024];
        int len;

        while ((len = in.read(buf)) > 0) {
            out.write(buf, 0, len);
        }
        in.close();
        out.close();
        logger.debug("Done copying contents of " + source.getName() + " to " + destination.getName());
    }

    public static void writePrettyPrintedJSONObjectToFile(JSONObject json, File jsonFile)
            throws JSONException, IOException {
        String prettyPrintedJSONString = json.toString(4);
        FileWriter writer = new FileWriter(jsonFile);
        writer.write(prettyPrintedJSONString);
        writer.close();
        logger.debug("Done writing JSON Object into a File: " + jsonFile.getAbsolutePath());
    }

    public static String readFileContentsToString(File file) throws IOException {
        FileInputStream stream = new FileInputStream(file);
        try {
            FileChannel fc = stream.getChannel();
            MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
            /* Instead of using default, pass in a decoder. */
            return Charset.defaultCharset().decode(bb).toString();
        } finally {
            stream.close();
        }
    }

    public static void writeStringToFile(String string, String fileName) throws IOException {
        BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
        writer.write(string);
        writer.flush();
        writer.close();
    }

}