JSP web application

JSP web application
	Chapter 5. How to develop a web application?

Servlets and JSPs can be combined in a single web application. Therefore we will use the servlet application created in the previous section, and just modify it to show how to use JSPs.

We could simply embed our Hello world message in the JSP file. But in practice it is often useful to call Obix code from a JSP file. Therefore we are going to first create an Obix service to get the text to be displayed, and then we will call that service from a JSP file.

To create an Obix service that returns the message, create file se_JSP_service.osc in directory pr_hello_web/work/obix/source_code/li_hello_web/ with the following content:

service JSP_service

   command get_hello_message
      out result type:string end
      
      script
         o_result = "<h3>Hello world</h3>"
      end
   end

end service

Now create file hello.jsp in directory pr_hello_web/work/web/ with the following content:

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<%@page import="li_hello_web.se_JSP_service"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>

    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP hello page</title>
    </head>

    <body>
        <p>The following message is returned from an Obix service:</p>
        <%= se_JSP_service.co_get_hello_message_command().getValue().java_value() %>
    </body>

</html>

Compile and build your project by executing the compile_and_build system file which is located in your project's root directory (i.e. compile_and_build.sh on Linux and compile_and_build.bat on Windows).

To package, deploy and run your application, proceed as described in the previous section about creating a servlet. But this time enter the following URL in your browser: http://127.0.0.1:8080/hello_web/hello.jsp


Servlet web application		Further information