Spring MVC实现文件下载

 下载文件①

下载文件需要将byte数组还原成文件。

首先使用mybatis将数据库中的byte数组查出来，指定文件名(包括格式)。然后使用OutputStream将文件输入

1. @RequestMapping(value = "downPhotoById")
2. public void downPhotoByStudentId(String id, final HttpServletResponse response){
3. PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id);
4. byte[] data = entity.getPhotoData();
5. String fileName = entity.getFileName()== null ? "照片.png" : entity.getFileName();
6. fileName = URLEncoder.encode(fileName, "UTF-8");
7. response.reset();
8. response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
9. response.addHeader("Content-Length", "" + data.length);
10. response.setContentType("application/octet-stream;charset=UTF-8");
11. OutputStream outputStream = new BufferedOutputStream(response.getOutputStream());
12. outputStream.write(data);
13. outputStream.flush();
14. outputStream.close();
15. }

1. <a href="<%=request.getContextPath() %>/downPhotoById.do?id=8000001">下载照片</a>

 下载文件②

/** * @Description 下载文件

* @author jxldjsn

* @date 2015年12月11日 下午6:11:33

* @param fileName

* @param file

* @return

* @throws IOException

*/

public ResponseEntity<byte[]> download(String fileName, File file) throws IOException {

String dfileName = new String(fileName.getBytes("gb2312"), "iso8859-1");

HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.APPLICATION_OCTET_STREAM); headers.setContentDispositionFormData("attachment", dfileName);

return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, HttpStatus.CREATED); }

 下载文件③

//文件下载 主要方法
  public static void download(HttpServletRequest request,
      HttpServletResponse response, String storeName, String contentType
       ) throws Exception {  

    request.setCharacterEncoding("UTF-8");
    BufferedInputStream bis = null;
    BufferedOutputStream bos = null;  

    //获取项目根目录
    String ctxPath = request.getSession().getServletContext()
        .getRealPath("");  

    //获取下载文件露肩
    String downLoadPath = ctxPath+"/uploadFile/"+ storeName;  

    //获取文件的长度
    long fileLength = new File(downLoadPath).length();  

    //设置文件输出类型
    response.setContentType("application/octet-stream");
    response.setHeader("Content-disposition", "attachment; filename="
        + new String(storeName.getBytes("utf-8"), "ISO8859-1"));
    //设置输出长度
    response.setHeader("Content-Length", String.valueOf(fileLength));
    //获取输入流
    bis = new BufferedInputStream(new FileInputStream(downLoadPath));
    //输出流
    bos = new BufferedOutputStream(response.getOutputStream());
    byte[] buff = new byte[2048];
    int bytesRead;
    while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
      bos.write(buff, 0, bytesRead);
    }
    //关闭流
    bis.close();
    bos.close();
  }  

}

下载直接访问控制器如：http:\\localhost:8080/springmvc/download.do

 下载文件④

1. @RequestMapping("/export")
2. public ResponseEntity<byte[]> export() throws IOException {
3. HttpHeaders headers = new HttpHeaders();
4. headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
5. headers.setContentDispositionFormData("attachment", "dict.txt");
6. return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(new File("C:/Users/Administrator/Desktop/a.txt")),
7. headers, HttpStatus.CREATED);
8. }