org.beangle.web.io.SplitStreamDownloader.java Source code

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Here is the source code for org.beangle.web.io.SplitStreamDownloader.java

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/* Copyright c 2005-2012.
 * Licensed under GNU  LESSER General Public License, Version 3.
 * http://www.gnu.org/licenses
 */
package org.beangle.web.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.time.StopWatch;
import org.beangle.web.mime.MimeTypeProvider;

/**
 * SplitStreamDownloader
 * <p>
 * Split download senario like this:
 * <li>Server first response:200</li>
 * 
 * <pre>
 * Content-Length=106786028
 * Accept-Ranges=bytes
 * </pre>
 * 
 * <li>Client send request :</li>
 * 
 * <pre>
 * Range: bytes=2000070-106786027
 * </pre>
 * 
 * <li>Server send next response:206</li>
 * 
 * <pre>
 * Content-Length=106786028
 * Content-Range=bytes 2000070-106786027/106786028
 * </pre>
 * 
 * @author chaostone
 */
public class SplitStreamDownloader extends DefaultStreamDownloader {

    public SplitStreamDownloader() {
        super();
    }

    public SplitStreamDownloader(MimeTypeProvider mimeTypeProvider) {
        super(mimeTypeProvider);
    }

    @Override
    public void download(HttpServletRequest request, HttpServletResponse response, InputStream input, String name,
            String display) {
        String attach = getAttachName(name, display);
        response.reset();
        addContent(request, response, attach);
        response.setHeader("Accept-Ranges", "bytes");
        response.setHeader("connection", "Keep-Alive");
        int length = 0;
        long start = 0L;
        long begin = 0L;
        long stop = 0L;
        StopWatch watch = new StopWatch();
        watch.start();
        try {
            length = input.available();
            stop = length - 1;
            response.setContentLength(length);
            String rangestr = request.getHeader("Range");
            if (null != rangestr) {
                String[] readlength = StringUtils.substringAfter(rangestr, "bytes=").split("-");
                start = Long.parseLong(readlength[0]);
                if (readlength.length > 1 && StringUtils.isNotEmpty(readlength[1])) {
                    stop = Long.parseLong(readlength[1]);
                }
                if (start != 0) {
                    response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
                    String crange = "bytes " + start + "-" + stop + "/" + length;
                    response.setHeader("Content-Range", crange);
                }
            }
            OutputStream output = response.getOutputStream();
            input.skip(start);
            begin = start;
            int size = 4 * 1024;
            byte[] buffer = new byte[size];
            for (int step = maxStep(start, stop, size); step > 0; step = maxStep(start, stop, size)) {
                int readed = input.read(buffer, 0, step);
                if (readed == -1)
                    break;
                output.write(buffer, 0, readed);
                start += readed;
            }
        } catch (IOException e) {
        } catch (Exception e) {
            logger.warn("download file error " + attach, e);
        } finally {
            IOUtils.closeQuietly(input);
            if (logger.isDebugEnabled()) {
                String percent = null;
                if (length == 0) {
                    percent = "100%";
                } else {
                    percent = ((int) (((start - begin) * 1.0 / length) * 10000)) / 100.0f + "%";
                }
                long time = watch.getTime();
                int rate = 0;
                if (start - begin > 0) {
                    rate = (int) (((start - begin) * 1.0 / time * 1000) / 1024);
                }
                logger.debug("{}({}-{}/{}) download {}[{}] in {} ms with {} KB/s",
                        array(attach, begin, stop, length, start - begin, percent, time, rate));
            }
        }
    }

    private Object[] array(Object... objects) {
        return objects;
    }

    public int maxStep(long start, long stop, int bufferSize) {
        if (stop - start + 1 >= bufferSize) {
            return bufferSize;
        } else {
            return (int) (stop - start + 1);
        }
    }

}