jdk的get和post请求的示例分析

        OutputStreamWriter out = null;
        HttpURLConnection conn = null;
        BufferedReader reader = null;
        StringBuilder response = new StringBuilder();
        URL httpUrl = null;
        try{
            httpUrl = new URL("http://www.baidu.com");
            //建立连接
            conn = (HttpURLConnection) httpUrl.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.setUseCaches(false);//设置不要缓存
            conn.setInstanceFollowRedirects(true);
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.connect();
            out = new OutputStreamWriter(conn.getOutputStream());
            out.write(params);
            out.flush();
            //读取响应
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String lines;
            while ((lines = reader.readLine()) != null) {
                lines = new String(lines.getBytes(), "utf-8");
                response.append(lines);
            }
            System.out.println(response.toString());
        }catch(Exception e){
            e.printStackTrace();
        }

/**
     * 发送GET请求
     *
     * @param url        目的地址
     * @param parameters 请求参数，Map类型。
     * @return 远程响应结果
     */
    public static String sendGet(String url, Map<String, String> parameters) {
        StringBuilder result = new StringBuilder();
        BufferedReader in = null;// 读取响应输入流
        StringBuilder sbParams = new StringBuilder();// 存储参数
        String params = "";// 编码之后的参数
        try {
            // 编码请求参数
            for (String name : parameters.keySet()) {
                sbParams.append(name).append("=").append(java.net.URLEncoder.encode(parameters.get(name), "UTF-8")).append("&");
            }
            String requestParam = sbParams.toString();
            params = requestParam.substring(0, requestParam.length() - 1);
            String fullUrl = url + "?" + params;
            logger.info("get请求：" + fullUrl);
            // 创建URL对象
            URL connURL = new URL(fullUrl);
            // 打开URL连接
            HttpURLConnection httpConn = (HttpURLConnection) connURL.openConnection();
            // 设置通用属性
            httpConn.setRequestProperty("Accept", "*/*");
            httpConn.setRequestProperty("Connection", "Keep-Alive");
            httpConn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
            // 建立实际的连接
            httpConn.connect();
            // Map<String, List<String>> headers = httpConn.getHeaderFields();
            // 定义BufferedReader输入流来读取URL的响应,并设置编码方式
            in = new BufferedReader(new InputStreamReader(httpConn.getInputStream(), StandardCharsets.UTF_8));
            String line;
            // 读取返回的内容
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
            logger.info("get请求结果：" + result.toString());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result.toString();
    }