2023年4月21日-关于远程feign调用实现文件上传下载

一、客户需求：做一个查询程序，客户提供一个excel模板，将查询结果保存到excel模板中，上传到文件服务，供客户下载使用。

二、代码实现

// 服务A，文件上传@ApiOperation("上传文件-demo")@PostMapping(value = "/uploadDemo/{busType}/{billId}")public ResBean uploadFile(@PathVariable("busType") String busType,                                          @PathVariable("billId") String billId,                                          @RequestParam(value = "file")  MultipartFile file                                         )  {    /**  ......省略上传逻辑  */  return null;}

// 服务B，feign客户端package com.xxxx.remote;import org.springframework.cloud.openfeign.FeignClient;import org.springframework.http.MediaType;import org.springframework.stereotype.Repository;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.multipart.MultipartFile;@Repository@FeignClient(name = "xxxxx")public interface FeignClient {    @PostMapping(value = "/xxxx/xxxx/{busType}/{billId}"            , produces = {MediaType.APPLICATION_JSON_UTF8_VALUE}            , consumes = MediaType.MULTIPART_FORM_DATA_VALUE    )    ResBean uploadFile(@PathVariable("busType") String busType,                                       @PathVariable("billId") String billId,                                       @RequestPart("file") MultipartFile file    );}

// 服务B，业务层public ResBean optexcel() throws IOException {        List dataList = new ArrayList();        for (int i = 0; i < 10; i++) {            UserEntity userEntity = new UserEntity();            userEntity.setName("张三" + i);            userEntity.setAge(20 + i);            userEntity.setTime(new Date(System.currentTimeMillis() + i));            dataList.add(userEntity);        }        //生成excel文档        Workbook workbook = ExcelExportUtil.exportExcel(new ExportParams("用户","用户信息"),                UserEntity.class, dataList);        MultipartFile file = workbookToCommonsMultipartFile(workbook, "用户.xls");        ResBean resbean = this.FeignClient.uploadFile(               "xxxxxx",               "111222333",                file                );        return resbean;    }    public static MultipartFile workbookToCommonsMultipartFile(Workbook workbook, String fileName) {        FileItemFactory factory = new DiskFileItemFactory(16, null);        FileItem fileItem = factory.createItem("file", "text/plain", true, fileName);        try {            OutputStream os = fileItem.getOutputStream();            workbook.write(os);            os.close();            MultipartFile multipartFile = new CommonsMultipartFile(fileItem);            return multipartFile;        } catch (Exception e) {            e.printStackTrace();        }        return null;    }

总结：  坑1：不加如下注解，  produces = {MediaType.APPLICATION_JSON_UTF8_VALUE}  consumes = MediaType.MULTIPART_FORM_DATA_VALUE  报错信息：  Current request is  not a multipart request  坑2：不使用@RequestPart  报错信息：the request was rejected because no multipart boundary was found  坑3：workbookToCommonsMultipartFile中factory.createItem方法中，第一参数，要和@RequestPart注解中value值一致  不一致报错信息：  Required request part 'file' is not present  坑4：上传到服务器的excel重新下载后，打开时，会提示文件损坏  这时候需要给excel做一下授信，授信成功，就可以正常打开了。  授信操作参考：https://jingyan.baidu.com/article/c85b7a64a7337d413aac9555.html