Android在线程中创建一个POST请求

    近日开发项目中遇到需要Android端与服务器进行网络通信的，网上资料找了一些大多数不好用或者代码不完整，找到一个能用的，稍加更改，就成了我的了，哈哈哈！

Android 端：

package com.example.votesys;

import android.os.Build;
import android.util.Log;

import androidx.annotation.RequiresApi;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.StringWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.stream.Collectors;
import static com.example.votesys.VotingActivity.post_url;

/**
 * Created by xiaowen on 2017/12/30.
 */
//使用POST更好
public class NetWorkService {


    /**
     * 使用post方式与服务器通讯
     * @param content
     * @return
     */
    @RequiresApi(api = Build.VERSION_CODES.N)
    public static String SendPostRequest(String content){
        HttpURLConnection conn = null;
        try {
            String Strurl = post_url;
            URL url = new URL(Strurl);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("ser-Agent", "Fiddler");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setConnectTimeout(5 * 1000);
            OutputStream outputStream = conn.getOutputStream();
            outputStream.write(URLEncoder.encode(content.toString(), "UTF-8").getBytes());
            outputStream.flush();
            outputStream.close();
            if(HttpURLConnection.HTTP_OK==conn.getResponseCode()){
                Log.i("PostGetUtil","post请求成功");

                InputStream inputStream = conn.getInputStream();
                String backcontent = new BufferedReader(new InputStreamReader(inputStream))
                        .lines().parallel().collect(Collectors.joining(System.lineSeparator()));
                backcontent= URLDecoder.decode(backcontent,"UTF-8");
                System.out.println(" 这是从服务器返回来的信息: "+backcontent);
                Log.i("PostGetUtil",backcontent);
                inputStream.close();
                return backcontent;
            }else {
                Log.i("PostGetUtil","post请求失败");return "not ok";
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            conn.disconnect();
        }
        return "error";
    }

    /**
     * 使用get方式与服务器通信
     * @param content
     * @return
     */
//    public static String SendGetRequest(String content){
//
//        HttpURLConnection conn=null;
//        try {
//
//            String Strurl="http://192.168.0.6:8080/test2/MyServlet?"+content;
//            URL url = new URL(Strurl);
//            conn = (HttpURLConnection) url.openConnection();
//            conn.setConnectTimeout(5000);
//            conn.setRequestMethod("GET");
//            if(HttpURLConnection.HTTP_OK==conn.getResponseCode()){
//                Log.i("PostGetUtil","get请求成功");
//                InputStream in=conn.getInputStream();
//                byte[] bytes = new byte[0];
//                bytes = new byte[in.available()];
//                in.read(bytes);
//                String backcontent = new String(bytes);
//
//                backcontent= URLDecoder.decode(backcontent,"UTF-8");
//                Log.i("PostGetUtil",backcontent);
//                in.close();
//                return "httpisok";
//            }
//            else {
//                Log.i("PostGetUtil","get请求失败");return "fail";
//            }
//
//        } catch (Exception e) {
//            e.printStackTrace();
//        }
//        finally{
//            conn.disconnect();
//        }
//        return "exception";
//    }
}

Servlet端：

package voteSystem;

import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.*;
import java.util.stream.Collectors;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.alibaba.fastjson.JSON;

/**
 * Servlet implementation class MyServlet
 */
@WebServlet("/Servlet1")//web.xml中不用配置servlet-mapping
public class Servlet1 extends HttpServlet {
    private static final long serialVersionUID = 1L;
    static Thread thread = null;
    static CountDownLatch count = new CountDownLatch(1);
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Servlet1() {
        super();
        // TODO Auto-generated constructor stub
       
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取请求发送的数据
//        String content=request.getQueryString();
       content=URLDecoder.decode(content,"UTF-8");
//        System.out.println("1="+content);
//
//        //向客户端返回数据
//        OutputStream os=response.getOutputStream();
//        String back="你好，我是服务端,收到get请求，正在处理！！！";
//        os.write(URLEncoder.encode(back,"UTF-8").getBytes());
//        os.flush();
//        os.close();
//    	doPost(request,response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取post请求发送的数据
    	System.out.println("开始Servlet1");
    	InputStream inputStream = request.getInputStream();
    	
    	String content = new BufferedReader(new InputStreamReader(inputStream))
    	.lines().parallel().collect(Collectors.joining(System.lineSeparator()));
        System.out.println("收到post请求");
        content=URLDecoder.decode(content,"UTF-8");//这里是处理后的内容
        System.out.println("收到post请求，json是："+content);
        
        //servlet传递数据到jsp
        System.out.println("前");              
        System.out.println("后");
        List< Map> list = toListMap(content); //此行json转换为list
        System.out.println("list"+list.toString());       
        ServletContext application=this.getServletContext();   
        application.setAttribute("list", content);
       
//        向客户端返回数据,阻塞等待数据

  
   //      try {
   //         count.await();
   //    } catch (InterruptedException e) {
   //         e.printStackTrace();
   //    } 
   //    System.out.println("All is finished.");
   //     count = new CountDownLatch(1);
        
        		OutputStream os=response.getOutputStream();
             String back="你好，我是服务端，收到post请求，正在处理！！！";
              os.write(URLEncoder.encode(back,"UTF-8").getBytes());
              os.flush();
              os.close();
              break;
//        	}
//        }
       
        System.out.println("结束Servlet1，投票结果如下：");
    }
    public static List> toListMap(String json){
        List