Java使用OKHttp进行文件上传

使用场景：服务端使用InputStream来接收文件

客户端使用post请求

headerMap用于存放请求头信息

paramsMap用于存放文件和字符串参数

public String postFile(String url, HashMap<String, String> headerMap, HashMap<String, Object> paramsMap) throws IOException{

        MultipartBody.Builder builder1 = new MultipartBody.Builder();
        builder1.setType(MultipartBody.FORM);
        for (Map.Entry<String, Object> stringObjectEntry : paramsMap.entrySet()) {
            String key = stringObjectEntry.getKey();
            Object value = stringObjectEntry.getValue();
            if (value instanceof File) {//如果请求的值是文件
                File file = (File) value;
                //MediaType.parse("application/octet-stream")以二进制的形式上传文件
                builder1.addFormDataPart("file", ((File) value).getName(), RequestBody.create(MediaType.parse("multipart/form-data"), file));
            } else {//如果请求的值是string类型
                builder1.addFormDataPart(key, value.toString());
            }
        }

        Request.Builder requestBuilder = new Request.Builder();
        requestBuilder.url(url);
    
    	// 添加请求头
        if(CollectionUtil.isNotEmpty(headerMap)){
            Set<String> keys = headerMap.keySet();
            for (String key : keys) {
                String val = headerMap.get(key);
                requestBuilder.addHeader(key, val);
            }
        }
        requestBuilder.post(builder1.build()).url(url);
        Request request = requestBuilder.build();

        try (Response response = client.newCall(request).execute()) {
            ResponseBody responseBody = response.body();
            if (Objects.isNull(responseBody)) {
                throw new RuntimeException("响应体为空");
            }
            String strResponse = responseBody.string();
            log.info("打印响应参数:{}", strResponse);
            return strResponse;
        } catch (Exception e) {
            log.error(e.toString(),e);
        }

    }

客户端支持上传多个文件，paramsMap中的value设置为File类型的文件即可

// 假设现在有多个list：List<File> files
Map<String, Object> paramsMap = new HashMap<>();
// 字符串类型参数正常设置即可
paramsMap.put("StringKey", "StringValue");
// 文件类型参数设置方式如下：
for(int i = 0; i < files.size(); i++) {
    paramsMap.put("file"+i, files.get(i));
}