com.iyonger.apm.web.util.FileDownloadUtils.java Source code

Introduction

Here is the source code for com.iyonger.apm.web.util.FileDownloadUtils.java

Source

/* 
 * 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. 
 */
package com.iyonger.apm.web.util;

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletResponse;
import java.io.*;

/**
 * File download utilities.
 *
 * @author JunHo Yoon
 * @since 3.0
 */
public abstract class FileDownloadUtils {

    private static final int FILE_DOWNLOAD_BUFFER_SIZE = 4096;
    private static final Logger LOGGER = LoggerFactory.getLogger(FileDownloadUtils.class);
    public static final int FILE_CHUNK_BUFFER_SIZE = 1024 * 1024;

    /**
     * Download the given file to the given {@link HttpServletResponse}.
     *
     * @param response {@link HttpServletResponse}
     * @param fileName file path
     * @return true if succeeded
     */
    public static boolean downloadFile(HttpServletResponse response, String fileName) {
        File file = new File(fileName);
        return downloadFile(response, file);
    }

    /**
     * Download the given file to the given {@link HttpServletResponse}.
     *
     * @param response {@link HttpServletResponse}
     * @param file     file path
     * @return true if succeeded
     */
    public static boolean downloadFile(HttpServletResponse response, File file) {
        if (file == null || !file.exists()) {
            return false;
        }
        boolean result = true;
        response.reset();
        response.addHeader("Content-Disposition", "attachment;filename=" + file.getName());
        response.setContentType("application/octet-stream");
        response.addHeader("Content-Length", "" + file.length());
        InputStream fis = null;
        byte[] buffer = new byte[FILE_DOWNLOAD_BUFFER_SIZE];
        OutputStream toClient = null;
        try {
            fis = new BufferedInputStream(new FileInputStream(file));
            toClient = new BufferedOutputStream(response.getOutputStream());
            int readLength;
            while (((readLength = fis.read(buffer)) != -1)) {
                toClient.write(buffer, 0, readLength);
            }
            toClient.flush();
        } catch (FileNotFoundException e) {
            LOGGER.error("file not found:" + file.getAbsolutePath(), e);
            result = false;
        } catch (IOException e) {
            LOGGER.error("read file error:" + file.getAbsolutePath(), e);
            result = false;
        } finally {
            IOUtils.closeQuietly(fis);
            IOUtils.closeQuietly(toClient);
        }
        return result;
    }
}