ResponseEntity之文件下载

在原生Servlet中我们一般通过HttpServletResponse来实现文件的下载功能。但是使用了SpringMVC后，可以无需使用原生的方法。通过ResponseEntity即可完成。

    @GetMapping("download")
    public ResponseEntity<byte[]> download(HttpSession httpSession) throws IOException {
        ServletContext servletContext = httpSession.getServletContext();
        String filePath = servletContext.getRealPath("kobe.jpg");
        Path path = Paths.get(filePath);
        InputStream inputStream = Files.newInputStream(path);
        byte[] bytes = new byte[inputStream.available()];
        inputStream.read(bytes);
        //创建HttpHeaders对象设置响应头信息
        MultiValueMap<String, String> headers = new HttpHeaders();
        //设置要下载方式以及下载文件的名字
        headers.add("Content-Disposition", "attachment;filename=1.jpg");
        //设置响应状态码
        HttpStatus statusCode = HttpStatus.OK;
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
        return responseEntity;
    }