springmvc服务端，模拟HTTP请求返回404

 public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            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)");

            connection.setDoInput(true);
            connection.setDoOutput(true);

            // 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));
                }
                InputStream inputStream = null;
                InputStreamReader inputStreamReader = null;
                BufferedReader reader = null;
                StringBuffer resultBuffer = new StringBuffer();
                String tempLine = null;


                inputStream = connection.getInputStream();
                inputStreamReader = new InputStreamReader(inputStream);
                reader = new BufferedReader(inputStreamReader);

                while ((tempLine = reader.readLine()) != null) {
                    resultBuffer.append(tempLine);
                }
            result=  resultBuffer.toString();

            } 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;
        }


去掉
connection.setRequestProperty("accept", "*/*");
或者改为
connection.setRequestProperty("Accept", "text/xml,text/javascript,text/html,application/json");