Display elements in jsp lists if servlet exists

Question

I have a 2 war (a.war , b.war) both were deployed in the tomcat. There are some jsp files in a.war which displays list of items in the list.

I need to display 5 items in tab on jsp page only if the b.war is also deployed , otherwise i will display only 3 items if b.war is not deployed.

Say there is servlet named /b/jobmgmt in b.war.

Can someone tell us,how can validate that b.war is deployed or not from the JSP page belongs to a.war using the servlet.

Thanks in advance.

Regards,

Raghavan

Answer 1

Basically, there are two possible approaches:

1) Define a <context-param> in web.xml of a.war, let's say checkURL, and put there the URL of the /b/jobmgmt as value, e.g. http://localhost:8080/b.jobmgmt. Then use getServletContext().getInitParameter("checkURL"); to get it in your JSP, and an HTTP call to verify, if the servlet is there and alive.

2) You can use cross-context communication as described e.g. here: https://blog.imaginea.com/cross-context-communication-between-web-applications/

Both approaches have their pros and cons, you have to choose according to your situation.