HttpURLConnection Post + 参数 请求

import android.os.Environment;
import android.os.Message;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * HttpURLConnection工具类
 */
public class HttpURLConnectionUtil {

    //POST请求 传递参数 ,下载文件

    /**
     * 下载文件保存到手机本地
     * @param path  http路径
     * @param param json字符串 传递的参数
     * @param filename 文件的名称
     * @return
     * @throws Exception
     */
    public static File getFileFromServer(String path, String param, String filename) throws Exception{
        Logs.i(path+param);
        // 如果相等的话表示当前的sdcard挂载在手机上并且是可用的
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            OutputStream out = null; //写
//            InputStream in = null;   //读
            Logs.i("开始下载");
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            //设置头部信息
//            conn.setRequestProperty("headerdata", "ceshiyongde");
            //一定要设置 Content-Type 要不然服务端接收不到参数
            conn.setRequestProperty("Content-Type", "application/Json; charset=UTF-8");
            //指示应用程序要将数据写入URL连接,其值默认为false（是否传参）
            conn.setDoOutput(true);
            conn.setUseCaches(false);

            conn.setConnectTimeout(5000);
            conn.setRequestProperty("Accept-Encoding", "identity");
            conn.setRequestProperty("Connection", "Keep-Alive");

            //传入参数
            out = conn.getOutputStream();
            out.write(param.getBytes());
            // 正文，正文内容其实跟get的URL中 '? '后的参数字符串一致
            //String content = "account=" + URLEncoder.encode("hahahaha", "UTF-8");
            //content +="&pswd="+URLEncoder.encode("heiheihei", "UTF-8");;
            // out.writeBytes(content);
            out.flush(); //清空缓冲区,发送数据
            out.close();

//            conn.connect();

            String fileType = conn.getContentType();//要下载文件的类型
            Logs.i("conn.getContentType() "+conn.getContentType());
            // 获取到文件的大小
//            pd.setMax(conn.getContentLength());
            Logs.i("file 的总大小 "+ conn.getContentLength());

            final int totalBytes = conn.getContentLength();

            InputStream is = conn.getInputStream();
            File sd1 = Environment.getExternalStorageDirectory();
            String path1 = sd1.getPath() + "/farmland/"+CacheUtil.Userid;
            path1 = "/storage/emulated/0/farmland/1";
            String fileName = filename+".jpg";
            File myfile1 = new File(path1);
            if (!myfile1.exists()) {
                myfile1.mkdirs();//创建想要保存到的文件夹 mkdirs()能同时创建多级文件夹，mkdir()只能创建一级文件夹
                Logs.i("创建文件夹成功 "+myfile1.getAbsolutePath());
            }
            File file = new File(myfile1, fileName);
            FileOutputStream fos = new FileOutputStream(file);
            BufferedInputStream bis = new BufferedInputStream(is);
            Logs.i("创建文件成功 "+file.getAbsolutePath());
            byte[] buffer = new byte[1024];
            int len;
            int total = 0;
            while ((len = bis.read(buffer)) != -1) {
                fos.write(buffer, 0, len);
                total += len;
                // 获取当前下载量
            }
            Logs.i(file.getPath()+"下载完成");
//            imagePath = "/storage/emulated/0/farmland/1/"+filename+".jpg";
            fos.close();
            bis.close();
            is.close();
            return file;
        } else {
            return null;
        }
    }
}

在接收端，这样获取参数：
String name = request.getParameter("account");
String pswd = request.getParameter("pswd");