Spring文件下载方式整理

项目中遇到文件下载,所以总结一下遇到的文件下载方式：

方法一，返回一个 ResponseEntity，响应实体返回一个字节数组，

 public ResponseEntity<byte[]> exportData() throws IOException {

        HttpHeaders headers=new HttpHeaders();
        headers.setContentDispositionFormData("attachment", new File(filePath).getName());
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);

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

 ResponseEntity用于构造标识整个http响应：状态码、头部信息以及相应体内容。因此我们可以使用其对http响应实现完整配置。

 

 方法二，通过向响应对象中写入字符流的方式实现。

 protected void service(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("application/octet-stream");
       
        resp.setHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode("中国", "utf-8")+".txt");
        PrintWriter os = resp.getWriter();
        String path = this.getServletContext().getRealPath("/download");
        Reader is = new BufferedReader(new FileReader(new File(path,"t.txt")));
        int len=0;
        char[] buffer = new char[200];
        while((len=is.read(buffer))!=-1){
            os.print(new String(buffer,0,len));
        }
        is.close();
        os.close();
    }
}