分享自己配置的HttpURLConnection请求数据工具类

>>该工具类传入string类型url返回string类型获取结果

import java.io.BufferedReader;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLDecoder;

/**

 * Created by ZJQ on 2016/5/20.

 */

//获取网络返回数据

public class GetNetJson {

    public String getJson(String urlstring) {

        String result = "";

        try {

            URL url = new URL(urlstring);

            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            connection.setConnectTimeout(4000);

            connection.setRequestMethod("GET");

            //设置通讯的头部信息,设置访问方式

            connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");

            connection.connect();

            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {

                //获取流

                InputStream inputStream = connection.getInputStream();

                BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));

                StringBuffer resultBuffer = new StringBuffer();

                String tempLine = null;

                while ((tempLine = br.readLine()) != null) {

                    resultBuffer.append(tempLine);

                }

                result = resultBuffer.toString();

                br.close();

                inputStream.close();

                return result;

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

        return result;

    }

}

>>期初由于该没有设置该属性导致app无法连接到网络

    connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");

调用方式：

String result = getNetJson.getJson("www.baidu.com");

以下是最近（18年8月）才写的urlconnection类，其实httpurlconectin是URLConnection的子类，看过源码的都知道。所以他俩大同小异

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.URL;

import java.net.URLConnection;

import java.util.List;

import java.util.Map;

public class RequestPayTool {

    /**

     * 向指定URL发送GET方法的请求

     *

     * @param url

     *            发送请求的URL

     * @param param

     *            请求参数，请求参数应该是name1=value1&name2=value2的形式。

     * @return URL所代表远程资源的响应

     */

    public static String sendGet(String url, String param) {

        String result = "";

        BufferedReader in = null;

        try {

            String urlName = url + "?" + param;

            URL realUrl = new URL(urlName);

            // 打开和URL之间的连接

            URLConnection conn = realUrl.openConnection();

            // 设置通用的请求属性

            conn.setConnectTimeout(60000);

//            conn.setRequestProperty("accept", "*/*");

//            conn.setRequestProperty("connection", "Keep-Alive");

//            conn.setRequestProperty("user-agent",

//                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");

            // 建立实际的连接

            conn.connect();

            // 获取所有响应头字段

            Map<String, List<String>> map = conn.getHeaderFields();

            // 遍历所有的响应头字段

            for (String key : map.keySet()) {

                System.out.println(key + "--->" + map.get(key));

            }

            // 定义BufferedReader输入流来读取URL的响应

            in = new BufferedReader(

                    new InputStreamReader(conn.getInputStream()));

            String line;

            while ((line = in.readLine()) != null) {

                result += "" + line;

            }

        } catch (Exception e) {

            System.out.println("##发送GET请求出现异常！" + e);

            e.printStackTrace();

        }

        // 使用finally块来关闭输入流

        finally {

            try {

                if (in != null) {

                    in.close();

                }

            } catch (IOException ex) {

                ex.printStackTrace();

            }

        }

        return result;

    }

    /**

     * 向指定URL发送POST方法的请求

     *

     * @param url

     *            发送请求的URL

     * @param param

     *            请求参数，请求参数应该是name1=value1&name2=value2的形式。

     * @return URL所代表远程资源的响应

     */

    public static String sendPost(String url, String param,int timeOut) {

        PrintWriter out = null;

        BufferedReader in = null;

        String result = "";

        try {

            URL realUrl = new URL(url);

            // 打开和URL之间的连接

            URLConnection conn = realUrl.openConnection();

            conn.setConnectTimeout(timeOut);

            // 设置通用的请求属性

//            conn.setRequestProperty("accept", "*/*");

//            conn.setRequestProperty("connection", "Keep-Alive");

//            conn.setRequestProperty("user-agent",

//                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");

            // 发送POST请求必须设置如下两行

            conn.setDoOutput(true);

            conn.setDoInput(true);

            // 获取URLConnection对象对应的输出流

            out = new PrintWriter(conn.getOutputStream());

            // 发送请求参数

            out.print(param);

            // flush输出流的缓冲

            out.flush();

            // 定义BufferedReader输入流来读取URL的响应

            in = new BufferedReader(

                    new InputStreamReader(conn.getInputStream()));

            String line;

            while ((line = in.readLine()) != null) {

                result += "" + line;

            }

        } catch (Exception e) {

            System.out.println("##发送POST请求出现异常！" + e);

            e.printStackTrace();

        }

        // 使用finally块来关闭输出流、输入流

        finally {

            try {

                if (out != null) {

                    out.close();

                }

                if (in != null) {

                    in.close();

                }

            } catch (IOException ex) {

                ex.printStackTrace();

            }

        }

        return result;

    }

}