OKhttp3.X 3.0上传图片文件及表单MultipartBody

okhttp3提供啦MultipartBody，可以上传Multipart表单

实现上传文件以及上传参数

  public static Request  getFileRequest(String url,File file,Map maps){
		  MultipartBody.Builder builder=  new MultipartBody.Builder().setType(MultipartBody.FORM);
		  if(maps==null){
			  builder.addPart( Headers.of("Content-Disposition", "form-data; name=\"file\";filename=\"file.jpg\""), RequestBody.create(MediaType.parse("image/png"),file)
				 ).build();
					  
		  }else{
			  for (String key : maps.keySet()) {
					builder.addFormDataPart(key, maps.get(key));
				}
			 
			   builder.addPart( Headers.of("Content-Disposition", "form-data; name=\"file\";filename=\"file.jpg\""), RequestBody.create(MediaType.parse("image/png"),file)
				 );
					 
		  }
		  RequestBody body=builder.build(); 
		  return   new Request.Builder().url(url).post(body).build();
		  
	  }

如果是参数，则通过addFormDataPart添加  如果是文件，则通过addPart添加