how to read config file when web service starts up

[Ravi Danum]

Hello,

How can a web service read from a config file at its startup? I know in servlets, the code would get called from the servlet's init method.

I thought of writing a handler, but handlers get called for each request and response.

I am using a servlet based web service (not EJB based ws) and JAX-WS.

Thanks for your help.

Ravi

[Omar Al Kababji]

user a listener, ServletContextListener and register it in your web.xml file.

[Ravi Danum]

Hello Omar,

I would use the ServletContextListener with a servlet, but is that the recommended way with a (servlet-based) webservice?

Thanks for your response.

Ravi

[Omar Al Kababji]

since its a (servlet-based) i would say yes.

[Peer Reynders]

Probably something along the lines of:

...
import javax.xml.ws.WebServiceContext;
import javax.annotation.Resource;
import javax.servlet.ServletContext;

@WebService
public class Hello {

...
    @WebMethod(exclude = true)
    @Resource 
    public void initializeContext(WebServiceContext wsContext) {
        MessageContext mc         = wsContext.getMessageContext();
        ServletContext context    = ((javax.servlet.ServletContext) mc.get(MessageContext.SERVLET_CONTEXT));
        String         paramValue = context.getInitParameter("ParamName");

        ...
    }
    ...
}

Hello.java
javax.annotation.Resource
javax.xml.ws.WebServiceContext
A little bit about Message Context in JAX-WS

[Ravi Danum]

Peer, Omar,

Thanks so much. This is perfect. I am so grateful for this information.

-Ravi

[Ravi Danum]

Peer,

I have tried the code:

...
import javax.xml.ws.WebServiceContext;
import javax.annotation.Resource;
import javax.servlet.ServletContext;

@WebService
public class Hello {

...
@WebMethod(exclude = true)
@Resource
public void initializeContext(WebServiceContext wsContext) {
MessageContext mc = wsContext.getMessageContext();
ServletContext context = ((javax.servlet.ServletContext) mc.get(MessageContext.SERVLET_CONTEXT));
String paramValue = context.getInitParameter("ParamName");

...
}
...
}

and I can't call: wsContext.getMessageContext() unless it is called from within an exposed web service method.
From Glassfish, I get this error:

java.lang.IllegalStateException: getMessageContext() can only be called while servicing a request

Do you know of another way to read some parameters (hopefully servlet initialization params from web.xml) from the initializeContext method?

Many thanks for your attention.

Ravi

[Peer Reynders]

Any chance you can use lazy initialization? Have every web method call the lazy initialization method with the MessageContext but only initialize on the first invocation.

[Ravi Danum]

Thanks, Peer that makes sense.

-Ravi

[Bibhu Biswal]

Hello Ravi,

I am new to web service, Could you please show the code snippet.

Bibhu