从Java应用程序调用Servlet

我想从Java应用程序调用Servlet。 问题是，调用似乎没有到达Servlet。 我没有收到任何错误，但是没有到达Servlet中的第一个输出“doPost”。 如果我在网络浏览器中打开URL，我当然得到了GET不支持的错误等，但至少我看到，有些事情发生了。

我使用以下代码（ActionPackage类只包含参数Vector并且是Serializable）：

Java应用程序：

ActionPackage p = new ActionPackage(); p.addParameter("TEST", "VALUE"); System.out.println(p); URL gwtServlet = null; try { gwtServlet = new URL("http://localhost:8888/app/PushServlet"); HttpURLConnection servletConnection = (HttpURLConnection) gwtServlet.openConnection(); servletConnection.setRequestMethod("POST"); servletConnection.setDoOutput(true); ObjectOutputStream objOut = new ObjectOutputStream(servletConnection.getOutputStream()); objOut.writeObject(p); objOut.flush(); objOut.close(); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } 

Servlet的：

 public class PushServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("doPost"); ObjectInputStream objIn = new ObjectInputStream(request.getInputStream()); ActionPackage p = null; try { p = (ActionPackage) objIn.readObject(); } catch (ClassNotFoundException e) { e.printStackTrace(); } System.out.println("Servlet received p: "+p); } 

}

出了什么问题？

谢谢。

Answer 1

只要你调用任何get方法， URLConnection就会被懒惰地执行。

将以下内容添加到代码中以实际执行HTTP请求并获取servlet响应主体。

 InputStream response = servletConnection.getInputStream(); 

也可以看看：

• 如何使用java.net.URLConnection来触发和处理HTTP请求？

Answer 2

尝试在try / catch块中包装doPost的整个主体：

 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { System.out.println("doPost"); ObjectInputStream objIn = new ObjectInputStream(request.getInputStream()); ActionPackage p = null; p = (ActionPackage) objIn.readObject(); System.out.println("Servlet received p: "+p); } catch (Throwable e) { e.printStackTrace(System.out); } } 

然后再次查看您的Servlet输出日志文件或窗口以获取可能有用的新exception。

Answer 3

 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { System.out.println("doPost"); ObjectInputStream objIn = new ObjectInputStream(request.getInputStream()); ActionPackage p = null; p = (ActionPackage) objIn.readObject(); System.out.println("Servlet rece p: "+p); } catch (Throwable e) { e.printStackTrace(System.out); } }