Java实现文件下载功能

来源：互联网发布：sqlserver 编辑：程序博客网时间：2024/06/10 12:02

Java实现文件下载功能

下载的主方法.

public ActionForward fileDownLoad(ActionMapping mapping,
   HttpServletRequest request, HttpServletResponse response)
   throws ServletException {
  String fileName = null;// 名称

  String realpath = "D:/crmSite/cdoc/";

  realpath = "D:/crmSite/cdoc/"
    + adform.getAdMat().substring(1);

  realpath = StrUtils.replace(realpath, "//", "/");

  BufferedInputStream bis = null;
  BufferedOutputStream bos = null;
  OutputStream fos = null;
  InputStream fis = null;
  fileName = realpath.substring(realpath.lastIndexOf("/") + 1, realpath.length());
  //System.out.println(realpath);
  try {
   response.setContentType(this.getContentType(fileName));
   response.setHeader("Content-disposition", "attachment;filename="
     + fileName);
   fis = new FileInputStream(realpath);
   bis = new BufferedInputStream(fis);
   fos = response.getOutputStream();
   bos = new BufferedOutputStream(fos);

   int bytesRead = 0;
   byte[] buffer = new byte[5 * 1024];
   while ((bytesRead = bis.read(buffer)) != -1) {
    bos.write(buffer, 0, bytesRead);// 将文件发送到客户端
   }
   bos.close();
   bis.close();
   fos.close();
   fis.close();

  } catch (IOException e) {
   response.reset();
   e.printStackTrace();
  } finally {
   try {
    if (fos != null) {
     fos.close();
    }
    if (bos != null) {
     bos.close();
    }
    if (fis != null) {
     fis.close();
    }
    if (bis != null) {
     bis.close();
    }
   } catch (IOException e) {

    System.err.print(e);
   }
  }
  return null;
}

设置文件类型

private String getContentType(String fileName) {
  String fileNameTmp = fileName.toLowerCase();
  String ret = "";
  if (fileNameTmp.endsWith("txt")) {
   ret = "text/plain";
  }
  if (fileNameTmp.endsWith("gif")) {
   ret = "image/gif";
  }
  if (fileNameTmp.endsWith("jpg")) {
   ret = "image/jpeg";
  }
  if (fileNameTmp.endsWith("jpeg")) {
   ret = "image/jpeg";
  }
  if (fileNameTmp.endsWith("jpe")) {
   ret = "image/jpeg";
  }
  if (fileNameTmp.endsWith("zip")) {
   ret = "application/zip";
  }
  if (fileNameTmp.endsWith("rar")) {
   ret = "application/rar";
  }
  if (fileNameTmp.endsWith("doc")) {
   ret = "application/msword";
  }
  if (fileNameTmp.endsWith("ppt")) {
   ret = "application/vnd.ms-powerpoint";
  }
  if (fileNameTmp.endsWith("xls")) {
   ret = "application/vnd.ms-excel";
  }
  if (fileNameTmp.endsWith("html")) {
   ret = "text/html";
  }
  if (fileNameTmp.endsWith("htm")) {
   ret = "text/html";
  }
  if (fileNameTmp.endsWith("tif")) {
   ret = "image/tiff";
  }
  if (fileNameTmp.endsWith("tiff")) {
   ret = "image/tiff";
  }
  if (fileNameTmp.endsWith("pdf")) {
   ret = "application/pdf";
  }
  return ret;
}

调用时只需要用URL或提交的方式提交到action即可