springboot 以IO流形式返回给前端_springboot fegin返回io流

1、Controller

@ApiOperation(value = "IO流返回给前端")
@GetMapping("fileView")
public void fileView(@ApiParam(value = "文件路径", required = true) @RequestParam String fileUrl, HttpServletResponse response) {
    fileService.fileView(fileUrl, response);
}
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2、Service

    /**
     * 以IO流的形式返回给前端
     *
     * @param fileUrl  文件路径
     * @param response resp
     */
    public void fileView(String fileUrl, HttpServletResponse response) {
        // 读取文件名 例：yyds.jpg
        String fileName = fileUrl.substring(fileUrl.lastIndexOf("/") + 1);
        try (FileInputStream inputStream = new FileInputStream(fileUrl);
             OutputStream outputStream = response.getOutputStream()) {
            byte[] data = new byte[1024];
            // 全文件类型（传什么文件返回什么文件流）
            response.setContentType("application/x-msdownload");
            response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
            response.setHeader("Accept-Ranges", "bytes");
            int read;
            while ((read = inputStream.read(data)) != -1) {
                outputStream.write(data, 0, read);
            }
            // 将缓存区数据进行输出
            outputStream.flush();
        } catch (IOException e) {
            log.error("失败", e);
            throw new Exception("exception");
        }
    }
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3、另外一种写法

如果为小文件，则可直接写入，无须循环，效率更高

byte[] data = new byte[inputStream.available()];
inputStream.read(data);
response.set
......
outputStream.write(data);
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