Question

I have a GWT Server which will connect o another server via RMI or CustomConnection. I would like to have a way of telling the GWT Server which connection type to use.

What I could think of :

1. Adding custom tag in web.xml
2. Create a normal file containing the value of the connection

Which one is better? And do you know any other optimal way?

Answer 1

If you know at startup time, I would go with a initialization parameter:

http://docs.oracle.com/cd/E11035_01/wls100/webapp/progservlet.html#wp159396

For example, the following entries in the Java EE standard Web Application deployment descriptor, web.xml, define two initialization parameters: greeting, which has a value of Welcome and person, which has a value of WebLogic Developer.

<servlet>
  ...
 <init-param>>
    <description>The salutation</description>
    <param-name>greeting</param-name>
    <param-value>Welcome</param-value>
  </init-param>
 <init-param>
    <description>name</description>
    <param-name>person</param-name>
    <param-value>WebLogic Developer</param-value>
  </init-param>
</servlet>

To retrieve initialization parameters, call the getInitParameter(String name) method from the parent javax.servlet.GenericServlet class. When passed the name of the parameter, this method returns the parameter’s value as a String.

Overriding the init() Method

You can have your servlet execute tasks at initialization time by overriding the init() method. The following code fragment reads the tags that define a greeting and a name in the J2EE standard Web Application deployment descriptor, web.xml:

 String defaultGreeting;
String defaultName;
 public void init(ServletConfig config) 
    throws ServletException {
  if ((defaultGreeting = getInitParameter("greeting")) == null)
    defaultGreeting = "Hello";
   if ((defaultName = getInitParameter("person")) == null)
    defaultName = "World";
}