fegin接口下载文件

服务提供端这里结合的是minio文件服务器：

controller，这里一定是void，不要指定返回内容

@RequestMapping("/file")
@RestController
public class FileSystemController {

    @Autowired
    private FileSystemService fileSystemService;

    @GetMapping("/download")
    public void getDownloadInput(@RequestParam(name = "bucketName") String bucketName, @RequestParam(name = "fileName") String fileName, HttpServletResponse response){
        try {
            fileSystemService.download(bucketName, fileName, response);
        }catch (Exception e){
           return;
        }

    }
}

service

@Override
    public void download(String bucketName, String fileName, HttpServletResponse response) throws Exception {
        response.reset();
        if (StringUtils.isEmpty(bucketName)) {
            response.sendError(500, "桶名称为空");
            return;
        }
        InputStream inputStream = null;
        BufferedInputStream bufferedInputStream = null;
        OutputStream outputStream = null;
        try {
            // 设置ContentType，响应内容为二进制数据流，编码为utf-8，此处设定的编码是文件内容的编码
            response.setContentType("application/octet-stream;charset=utf-8");
            // 以（Content-Disposition: attachment; filename="filename.jpg"）格式设定默认文件名，设定utf编码，此处的编码是文件名的编码，使能正确显示中文文件名
            response.setHeader("Content-Disposition", "attachment;fileName=" + fileName + ";filename*=utf-8''" + URLEncoder.encode(fileName, "utf-8"));
            inputStream = fileSystemUtil.getObject(bucketName, fileName);
            //使用这个buffereInputStream 为了防止大文件内存溢出
            bufferedInputStream = new BufferedInputStream(inputStream);
            outputStream = response.getOutputStream();
            //每次取出5M
            byte[] buffer = new byte[1024 * 1024 * 5];
            int len;
            while ((len = bufferedInputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, len);
            }
        } catch (Exception e) {
            log.error("下载文件异常：{}", fileName, e);
        } finally {
            if (inputStream!=null){
                inputStream.close();
            }
            if (outputStream!=null){
                outputStream.close();
            }
            if (bufferedInputStream!=null){
                bufferedInputStream.close();
            }
        }

    }

消费者端：

feginClint端

@FeignClient("filesystem")
public interface FileSystemFeginClient {

    @GetMapping("/filesystem/file/download")
    Response getDownloadInput(@RequestParam(name = "bucketName") String bucketName, @RequestParam(name = "fileName") String fileName);


}

controller使用

@GetMapping("/download")
    public void getDownloadInput(@RequestParam(name = "bucketName") String bucketName, @RequestParam(name = "fileName") String fileName, HttpServletResponse response){
        Response response = fileSystemFeginClient.getDownloadInput(bucketName,fileName);
        
        response.reset();
        InputStream inputStream = null;
        BufferedInputStream bufferedInputStream = null;
        OutputStream outputStream = null;
        try {
            // 设置ContentType，响应内容为二进制数据流，编码为utf-8，此处设定的编码是文件内容的编码
            response.setContentType("application/octet-stream;charset=utf-8");
            // 以（Content-Disposition: attachment; filename="filename.jpg"）格式设定默认文件名，设定utf编码，此处的编码是文件名的编码，使能正确显示中文文件名
            response.setHeader("Content-Disposition", "attachment;fileName=" + fileName + ";filename*=utf-8''" + URLEncoder.encode(fileName, "utf-8"));
            inputStream = response.body().asInputStream();
            //使用这个buffereInputStream 为了防止大文件内存溢出
            bufferedInputStream = new BufferedInputStream(inputStream);
            outputStream = response.getOutputStream();
            //每次取出5M
            byte[] buffer = new byte[1024 * 1024 * 5];
            int len;
            while ((len = bufferedInputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, len);
            }
        } catch (Exception e) {
            log.error("下载文件异常：{}", fileName, e);
        } finally {
            if (inputStream!=null){
                inputStream.close();
            }
            if (outputStream!=null){
                outputStream.close();
            }
            if (bufferedInputStream!=null){
                bufferedInputStream.close();
            }
        }    }