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;
    }
}