Spring Cloud Feign如何获得接口返回的文件流

男娘i 2024-03-17 00:20 40阅读 0赞

通过Feign实现微服务间接口调用，返回stream，从而让通过stream实现文件的下载、页面图片、视频等展示成为可能，实现代码如下。

### 服务端 ###

#### **Controller** ####

@GetMapping(value = "/fileStream/{fileId}")
    public void getFileStream(@PathVariable(value = "fileId") String fileId, HttpServletResponse httpServletResponse) {
        service.getFileStream(fileId, httpServletResponse);
    }

#### **Service** ####

public void getFileStream(String fileId, HttpServletResponse response) {
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            UploadFileInfo uploadFileInfo = selectByPrimaryKey(fileId);
            String filePath = uploadFileInfo.getFilePath();
            File file = new File(filePath);
            response.setCharacterEncoding("utf-8");
            String contentType = contentType(filePath);
            response.setContentType(contentType);
            bis = new BufferedInputStream(new FileInputStream(file));
            bos = new BufferedOutputStream(response.getOutputStream());
            readStream(bis, bos);
            bos.flush();
        } catch (Exception e) {
            e.printStackTrace();
            response.setStatus(500);
        } finally {
            closeBuffered(bis, bos);
        }
    }

### 微服务客户端 ###

#### **定义接口** ####

import feign.Response;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.http.MediaType;
    import org.springframework.stereotype.Service;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PathVariable;
    
    @FeignClient(name = "COMMON-UPLOAD")
    @Service
    public interface UploadService {
        @GetMapping(value = "/uploads/fileStream/{fileId}", consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
        Response getFileStream(@PathVariable("fileId") String fileId);
    }

#### **客户端Controller** ####

@GetMapping("/identityInfoStream/{organId}")
    public void getIdentityInfoStream(@PathVariable String organId, HttpServletResponse httpServletResponse) {
        organStaffService.getIdentityInfoStream(organId, httpServletResponse);
    }

#### **客户端Service** ####

public void getIdentityInfoStream(String organId, HttpServletResponse httpServletResponse) {
        Example example = new Example(PubOrganStaff.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("organId", organId);
        criteria.andEqualTo("extType", "identityInfo");
        List<PubOrganStaff> staffList = selectByExample(example);
        String fileId = ObjectUtils.isEmpty(staffList) ? null : staffList.get(0).getExtValue();
    
        // Feign接口
        Response response = uploadService.getFileStream(fileId);
    
        Response.Body body = response.body();
    
        InputStream fileInputStream;
        OutputStream outStream;
        try {
            fileInputStream = body.asInputStream();
            outStream = httpServletResponse.getOutputStream();
    
            byte[] bytes = new byte[1024];
            int len;
            while ((len = fileInputStream.read(bytes)) != -1) {
                outStream.write(bytes, 0, len);
            }
            fileInputStream.close();
            outStream.close();
            outStream.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }