图片视频访问servlet(支持苹果视频断点续传)

package com.sm.common.servlet;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.util.UriUtils;
import com.sm.common.config.Global;

/**
 * 查看CK上传的图片
 * @author ThinkGem
 * @version 2014-06-25
 */
public class UserfilesDownloadServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;
    private Logger logger = LoggerFactory.getLogger(getClass());

    public void fileOutputStream(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String filepath = request.getRequestURI();
        int index = filepath.indexOf(Global.USERFILES_BASE_URL);
        if (index >= 0) {
            filepath = filepath.substring(index + Global.USERFILES_BASE_URL.length());
        }
        try {
            filepath = UriUtils.decode(filepath, "UTF-8");
        } catch (UnsupportedEncodingException e1) {
            logger.error(String.format("解释文件路径失败，URL地址为%s", filepath), e1);
        }
        File file = new File(Global.getUserfilesBaseDir() + Global.USERFILES_BASE_URL + filepath);
        logger.debug("===" + Global.getUserfilesBaseDir() + Global.USERFILES_BASE_URL + filepath + "===");
        RandomAccessFile randomFile = new RandomAccessFile(file, "r");// 只读模式
        long contentLength = randomFile.length();
        String range = request.getHeader("Range");
        int start = 0, end = 0;
        if (range != null && range.startsWith("bytes=")) {
            String[] values = range.split("=")[1].split("-");
            start = Integer.parseInt(values[0]);
            if (values.length > 1) {
                end = Integer.parseInt(values[1]);
            }
        }
        int requestSize = 0;
        if (end != 0 && end > start) {
            requestSize = end - start + 1;
        } else {
            requestSize = Integer.MAX_VALUE;
        }

        byte[] buffer = new byte[4096];
        response.setContentType("video/mp4");
        response.setHeader("Accept-Ranges", "bytes");
        response.setHeader("ETag", file.getName());
        response.setHeader("Last-Modified", new Date().toString());
        // 第一次请求只返回content length来让客户端请求多次实际数据
        if (range == null) {
            response.setHeader("Content-length", contentLength + "");
        } else {
            // 以后的多次以断点续传的方式来返回视频数据
            response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);// 206
            long requestStart = 0, requestEnd = 0;
            String[] ranges = range.split("=");
            if (ranges.length > 1) {
                String[] rangeDatas = ranges[1].split("-");
                requestStart = Integer.parseInt(rangeDatas[0]);
                if (rangeDatas.length > 1) {
                    requestEnd = Integer.parseInt(rangeDatas[1]);
                }
            }
            long length = 0;
            if (requestEnd > 0) {
                length = requestEnd - requestStart + 1;
                response.setHeader("Content-length", "" + length);
                response.setHeader("Content-Range", "bytes " + requestStart + "-" + requestEnd + "/" + contentLength);
            } else {
                length = contentLength - requestStart;
                response.setHeader("Content-length", "" + length);
                response.setHeader("Content-Range",
                        "bytes " + requestStart + "-" + (contentLength - 1) + "/" + contentLength);
            }
        }
        OutputStream out = response.getOutputStream();
        try {

            int needSize = requestSize;
            randomFile.seek(start);
            while (needSize > 0) {
                int len = randomFile.read(buffer);
                if (needSize < buffer.length) {
                    out.write(buffer, 0, needSize);
                } else {
                    out.write(buffer, 0, len);
                    if (len < buffer.length) {
                        break;
                    }
                }
                needSize -= buffer.length;
            }
        } catch (FileNotFoundException e) {
            request.setAttribute("exception", new FileNotFoundException("请求的文件不存在"));
            request.getRequestDispatcher("/WEB-INF/views/error/404.jsp").forward(request, response);
        } catch (Exception e1) {
            request.setAttribute("exception", e1);
            request.getRequestDispatcher("/WEB-INF/views/error/404.jsp").forward(request, response);
        } finally {
            randomFile.close();
            out.close();
        }

    }

    public void fileOutputStream2(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String filepath = req.getRequestURI();
        int index = filepath.indexOf(Global.USERFILES_BASE_URL);
        if (index >= 0) {
            filepath = filepath.substring(index + Global.USERFILES_BASE_URL.length());
        }
        try {
            filepath = UriUtils.decode(filepath, "UTF-8");
        } catch (UnsupportedEncodingException e1) {
            logger.error(String.format("解释文件路径失败，URL地址为%s", filepath), e1);
        }
        File file = new File(Global.getUserfilesBaseDir() + Global.USERFILES_BASE_URL + filepath);
        try {
            if (filepath.endsWith(".mp4")) {
                resp.setContentType("video/mpeg4; charset=utf-8");
                resp.setHeader("Content-disposition", "attachment;filename=" + file.getName());
            } else {
                resp.setHeader("Content-Type", "application/octet-stream");
            }
            FileCopyUtils.copy(new FileInputStream(file), resp.getOutputStream());

            return;
        } catch (FileNotFoundException e) {
            req.setAttribute("exception", new FileNotFoundException("请求的文件不存在"));
            req.getRequestDispatcher("/WEB-INF/views/error/404.jsp").forward(req, resp);
        } catch (Exception e1) {
            req.setAttribute("exception", e1);
            req.getRequestDispatcher("/WEB-INF/views/error/404.jsp").forward(req, resp);
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        fileOutputStream(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        fileOutputStream(req, resp);
    }
}