2016-09-15 82 views
6

服务器收到来自两个客户端的请求 - Raspberry Pi和Android应用程序,都使用HttpURLConnection发送请求。我需要与theese请求传递参数,例如:如何从HttpServletRequest(Tomcat 9.0)获取查询参数?

http://192.168.0.10:8080/MyProject/MyServer/rpi/checktask?rpi="rpi" 

做它:

String requestUrl = "http://192.168.0.10:8080/MyProject/MyServer/rpi"; 
String query = String.format("/checktask?rpi=%s", 
         URLEncoder.encode("rpi", "UTF-8")); 
URL url = new URL(requestUrl + query); 
conn = (HttpURLConnection) url.openConnection(); 
conn.setRequestMethod("GET"); 
conn.setDoInput(true); 
conn.setRequestProperty("Accept-Charset", "UTF-8"); 
conn.connect(); 

的servlet有注释:

@WebServlet(name = "MyServer", urlPatterns = { "/MyServer/rpi/*", "/MyServer/app/*"}) 

但是当Servlet的获取请求,如上以下情况:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 

String path = request.getRequestURI();  // /MyProject/MyServer/rpi/* 
String query = request.getQueryString(); // null 
String context = request.getContextPath(); // /MyProject 
String servlet = request.getServletPath(); // /MyServer/rpi 
String info = request.getPathInfo();  // /* 
} 

虽然根据这些问题的答案: How to use @WebServlet to accept arguments (in a RESTFul way)?How come request.getPathInfo() in service method returns null?

它应该是这样的:

String path = request.getRequestURI();  // /MyProject/MyServer/rpi//checktask?rpi="rpi" 
String query = request.getQueryString(); // rpi="rpi" 
String context = request.getContextPath(); // /MyProject 
String servlet = request.getServletPath(); // /MyServer/rpi 
String info = request.getPathInfo();  // /checktask?rpi="rpi" 

我在做什么错?

+0

如果您尝试手动点击网址(例如,使用浏览器)是否有效? – Taylor

+0

它不适用于浏览器和应用程序。 – Katrikken

+0

我的回答是垃圾,对不起。我现在有点困惑,并且正在阅读Servlet规范,这个主题的百分之一时间.... :-( – gsl

回答

8

你的URL字符串是

http://192.168.0.10:8080/MyProject/MyServer/rpi/checktask?rpi="rpi" 

在上面的字符串参数的名称是 “RPI”。

下面的代码将为您提供参数“rpi”所需的值。