How to use annotations instead of web.xml in the servlet to specify url

≯℡__Kan透↙ 提交于 2019-12-17 20:21:33

问题


How to provide an annotation mapping for web.XML in annotation. I have done with web.XML. I want to try with Annotation mapping, like so:

<web-app> 
  <servlet-mapping> 
  </servlet-mapping> 
</web-app>

回答1:


A simple example is :

@WebServlet(value="/hello")
public class HelloServlet extends HttpServlet {

    @Override
    public void doGet(HttpServletRequest request,HttpServletResponse response)
        throws ServletException, IOException {
    PrintWriter out = response.getWriter();

    // then write the data of the response
    String username = request.getParameter("username");
    if (username != null && username.length() > 0) {
        out.println("<h2>Hello, " + username + "!</h2>");
       }
    }

}



回答2:


Annotation represents the metadata. If you use annotation, deployment descriptor (web.xml file) is not required. But you should have tomcat7 as it will not run in the previous versions of tomcat. @WebServlet annotation is used to map the servlet with the specified name.

@WebServlet("/Simple")
public class Simple extends HttpServlet {
    private static final long serialVersionUID = 1L;

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


        response.setContentType("text/html");
        PrintWriter out=response.getWriter();

        out.print("<html><body>");
        out.print("<h3>Hello Servlet</h3>");
        out.print("</body></html>");
    }

}


来源:https://stackoverflow.com/questions/17236743/how-to-use-annotations-instead-of-web-xml-in-the-servlet-to-specify-url

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