HttpClient发送MultipartFile多文件及多参数请求

1、环境准备：

        
            commons-httpclient
            commons-httpclient
            3.1
        
        
            org.apache.httpcomponents
            httpmime
            4.5.3
        

2、Java中发送httpClient请求：

/**
     * HttpClient post multipart/form-data数据实现多文件上传
     * @param url
     * @param headers 头部参数
     * @param body body参数，json字符串
     * @param multipartFiles 文件列表
     * @param fileParName 接收的文件名
     * @return
     */
    public static String sendFilePost(String url, Map headers, String body,List multipartFiles,String fileParName) {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPost httppost = new HttpPost(url);
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        builder.setCharset(java.nio.charset.Charset.forName("UTF-8"));
        //单个文件
        String fileName = null;
        MultipartFile multipartFile = null;
        for (int i = 0; i < multipartFiles.size(); i++) {
            //第一个参数为 相当于 Form表单提交的file框的name值 第二个参数就是我们要发送的InputStream对象了
            //第三个参数是文件名
            //3)
            multipartFile = multipartFiles.get(i);
            fileName = multipartFile.getOriginalFilename();
            InputStream inputStream = null;
            try {
                inputStream = multipartFile.getInputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
            builder.addBinaryBody(fileParName,inputStream, ContentType.MULTIPART_FORM_DATA, fileName);// 文件流
        }
        //4)构建请求参数 普通表单项
		/*	StringBody stringBody = new StringBody("12", ContentType.MULTIPART_FORM_DATA);
			builder.addPart("id", stringBody);*/
        //决中文乱码
        ContentType contentType = ContentType.create(HTTP.PLAIN_TEXT_TYPE, Consts.UTF_8);
        builder.addTextBody("paramStr", body, contentType);
        HttpEntity entity = builder.build();
        if (null!=headers&&headers.size()>0){
            for (Map.Entry entry : headers.entrySet()) {
                httppost.addHeader(entry.getKey(),entry.getValue());
            }
        }
        httppost.setEntity(entity);
        CloseableHttpResponse response = null;
        try {
            response = httpclient.execute(httppost);
        } catch (IOException e) {
            logger.error("请求出错:" + url, e);
            return null;
        }
        String result = null;
        try {
            if(response!=null){
                HttpEntity httpEntity = response.getEntity();
                if (httpEntity != null && response.getStatusLine().getStatusCode()== HttpURLConnection.HTTP_OK) {// 判断请求状态
                    result = EntityUtils.toString(httpEntity);
                }
            }
        } catch (Exception e) {
            logger.error("请求出错:" + url, e);
        } finally {
            try {
                if(response!=null){
                    response.close();
                }
            } catch (IOException e) {
                logger.error("请求出错:" + url, e);
            }
        }
        logger.info("请求的URL:" + url + ", 返回结果:" + result);
        return result;
    }

3、后端服务restful接口接参：

    @Operation(summary = "获取附件")
    @PostMapping("/xxx")
    private void sendfilepost(@RequestParam(value = "file") List mulFiles,@RequestParam(value = "paramStr") String json){
        /**这里处理自己的逻辑*/
    }

4、模拟2中调用

/**将普通文件转成MultipartFile文件*/
public static MultipartFile getMultipartFile(File file) {
        FileItem item = new DiskFileItemFactory().createItem("file"
                , MediaType.MULTIPART_FORM_DATA_VALUE
                , true
                , file.getName());
        try (InputStream input = new FileInputStream(file);
             OutputStream os = item.getOutputStream()) {
            // 流转移
            IOUtils.copy(input, os);
        } catch (Exception e) {
            throw new IllegalArgumentException("Invalid file: " + e, e);
        }

        return new CommonsMultipartFile(item);
}


public static void main(String[] args) {
    String url = "请求的服务路径";
    File f = new File("D:\\test");
    File[] files = f.listFiles();
    List multiFiles = new ArrayList();
    for(File tempFile:files){
       MultipartFile cMultiFile = getMultipartFile(tempFile);
       multiFiles.add(cMultiFile);
    }
    String restr = sendFilePost(url, null, JSON.toJSONString(paramMap),multiFiles,"file");
}