Android 使用HttpURLConnection实现Http请求

//package com.example.red_butterfly.teacher_vote;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Random;

/**
 * Created by horou_dsk on 2017/8/3.
 */

public class HttpClient {

    static HttpURLConnection HttpGetUrlConnection = null;
    static HttpURLConnection HttpPostUrlConnection = null;

    public static String sendHttpGet(String url){
        URL _url = null;
        //打开连接
        try {
            _url = new URL(url);
            HttpGetUrlConnection = (HttpURLConnection) _url.openConnection();
            //添加请求头 setRequestProperty
            //HttpGetUrlConnection.setRequestProperty("x-forwarded-for","255.255.255.255");
            if(200 == HttpGetUrlConnection.getResponseCode()){
                //得到输入流
                InputStream is =HttpGetUrlConnection.getInputStream();
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                byte[] buffer = new byte[1024];
                int len = 0;
                while(-1 != (len = is.read(buffer))){
                    baos.write(buffer,0,len);
                    baos.flush();
                }
                return baos.toString("utf-8");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

        return "";
    }

    public static String sendHttpPost(String url){
        URL _url = null;
        try {
            _url = new URL(url);
            HttpPostUrlConnection = (HttpURLConnection) _url.openConnection();
            HttpPostUrlConnection.setRequestMethod("POST");// 提交模式
            // conn.setConnectTimeout(10000);//连接超时 单位毫秒
            // conn.setReadTimeout(2000);//读取超时 单位毫秒
            // 发送POST请求必须设置如下两行
            HttpPostUrlConnection.setDoOutput(true);
            HttpPostUrlConnection.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            PrintWriter printWriter = new PrintWriter(HttpPostUrlConnection.getOutputStream());
            // 发送请求参数
            printWriter.write("");//post的参数 xx=xx&yy=yy
            // flush输出流的缓冲
            printWriter.flush();
            //开始获取数据
            BufferedInputStream bis = new BufferedInputStream(HttpPostUrlConnection.getInputStream());
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            int len;
            byte[] arr = new byte[1024];
            while((len=bis.read(arr))!= -1){
                bos.write(arr,0,len);
                bos.flush();
            }
            bos.close();
            return bos.toString("utf-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }
}