servlet中的post请求无反应，该怎么解决

客户端代码

public class User {
    public static void main(String[] args) throws Exception {
        URL url=new URL("http://localhost:8080/web//Post_demo");
         String js=
                    "  {\r\n" + 
                    "    \"name\": \"zhangsan\",\r\n" + 
                    "    \"age\": \"10\",\r\n" + 
                    "    \"phone\": \"11111\",\r\n" + 
                    "    \"email\": \"11111@11.com\"\r\n" + 
                    "  }";
        HttpURLConnection conn=(HttpURLConnection) url.openConnection();     
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length",js.length()+"");
        conn.setDoOutput(true);      
        conn.getOutputStream().write(js.getBytes());

         } 
    }

服务端

@WebServlet("/Post_demo")
public class Post_demo extends HttpServlet{
    private static final long serialVersionUID = 1L;
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        StringBuffer jb=new StringBuffer();
        String js;
        BufferedReader bf=req.getReader();
        while((js=bf.readLine())!=null) {
            jb.append(js);
        }
        JsonObject jsonObject = (JsonObject) new JsonParser().parse(jb.toString());
        System.out.println("name:" + jsonObject.get("name").getAsString());
        System.out.println("age:" + jsonObject.get("age").getAsInt());
        System.out.println("phone:" + jsonObject.get("phone").getAsString());
        System.out.println("email:" + jsonObject.get("email").getAsString());
    }
}

启动后两边都没有报错也没有反应，到底是哪儿出错了

https://blog.csdn.net/m0_37672234/article/details/73748337