如何使用 Android 将 .pdf .doc .txt 文件上传到服务器（mysql 数据库）

我在将文件上传到服务器时遇到一些困难，我需要知道使用名称值对上传文件的完整代码。听到的是我的 android 代码，我只得到我的文件路径，如何将其上传到服务器，引用为“nameValuePairs.add(new BasicNameValuePair("attachment", selectedFilePath));”

       String selectedFilePath="downloads/harry.txt"  //(My file Path)



        InputStream is = null;
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
        nameValuePairs.add(new BasicNameValuePair("postiontitle", positiontitle));
        nameValuePairs.add(new BasicNameValuePair("description", description));
        nameValuePairs.add(new BasicNameValuePair("jobtype", jobtype));
        nameValuePairs.add(new BasicNameValuePair("visatype", visatype));



  if (selectedFilePath != null)
        {
            nameValuePairs.add(new BasicNameValuePair("attachment", selectedFilePath));


        }


        try {


            HttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new                                  HttpPost("http://10.0.3.2/dfsdsd/postjob");
            // HttpPost httpPost = new 
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            is = entity.getContent();
            int code = response.getStatusLine().getStatusCode();
            String rescode = String.valueOf(code);




            //result=is.toString();
            return rescode;
        } catch (MalformedURLException e) {
            return "No Internet";
        } catch (IOException e) {
            return "No Internet";
        }
    }

使用 Retrofit 和 Okhttp。

public static final String MULTIPART_FORM_DATA = "multipart/form-data";

 @NonNull
 private RequestBody createPartFromString(String descriptionString) {  
   return RequestBody.create(
        MediaType.parse(MULTIPART_FORM_DATA), descriptionString);
 }

 @NonNull
 private MultipartBody.Part prepareFilePart(String partName, Uri fileUri) {  
// https://github.com/iPaulPro/aFileChooser/blob/master/aFileChooser/src/com/ipaulpro/afilechooser/utils/FileUtils.java
// use the FileUtils to get the actual file by uri
File file = FileUtils.getFile(this, fileUri);

// create RequestBody instance from file
RequestBody requestFile =
    RequestBody.create(MediaType.parse(MULTIPART_FORM_DATA), file);

// MultipartBody.Part is used to send also the actual file name
return MultipartBody.Part.createFormData(partName, file.getName(), requestFile);
}