import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.URL;import java.net.URLConnection;/** * @author jiaql * @create 2017-12-21 14:57 */public class HttpRequestUtils {    /**     * 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 所代表远程资源的响应结果     */    public static String sendPost(String url, String param) {        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();            // 设置通用的请求属性            conn.setRequestProperty("accept", "*/*");            conn.setRequestProperty("Content-type", "application/json");            conn.setRequestProperty("connection", "Keep-Alive");            conn.setRequestProperty("user-agent",                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");            conn.setReadTimeout(15000);            // 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(),"utf-8"));            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;    }    /**     * 向指定URL发送GET方法的请求     *     * @param url     *            发送请求的URL     * @return URL 所代表远程资源的响应结果     */    public static String sendGet(String url) {        String result = "";        BufferedReader in = null;        try {            String urlNameString = url;            URL realUrl = new URL(urlNameString);            // 打开和URL之间的连接            URLConnection connection = realUrl.openConnection();            // 设置通用的请求属性            connection.setRequestProperty("accept", "*/*");            connection.setRequestProperty("connection", "Keep-Alive");            connection.setRequestProperty("user-agent",                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");            // 建立实际的连接            connection.connect();            // 获取所有响应头字段//            Map
     
      > map = connection.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(                    connection.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 (Exception e2) {                e2.printStackTrace();            }        }        return result;    }}