没有XML的Spring4-web.xml-转换为Java

Question

I do have couple of JNDI resources in my web.xml

This is for reading a external property file and path depends on environment.

<resource-ref id="resourceRef">
    <res-ref-name>config/file</res-ref-name>
    <res-type>java.lang.String</res-type>
    <res-auth>Container</res-auth>
    <res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>

This is for JNDI JDBC DB definition

    <resource-ref id="MyDatabase">
    <description></description>
    <res-ref-name>jdbc/MyDB</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
    <res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>     

and this for old ejb (EJB2.x)

<ejb-ref id="service">
    <description />
    <ejb-ref-name>ejb/AgencyService</ejb-ref-name>
    <ejb-ref-type>Session</ejb-ref-type>
    <home>ejb.Home</home>
    <remote>ejb.Service</remote>
</ejb-ref>

How can translate these resources to Java (Servlet 3.x)? An existing application is migrating from servlet 2.5 and EJB 2.x to Servlet3, Rest and EJB3. My new application uses Spring4 (MVC, Security etc) and OpenJPA 2.1.x. Our design goal is not to use "xml" (no web.xml, SpringContext.xml etc).

I created Java class that extends AbstractAnnotationConfigDispatcherServletInitializer

that would be equivalent to Web.xml.

How can I migrate resource-ref and ejb-ref to Java class??

Much appreciated your help!

Note :- edited

Answer 1

Basically Spring and JEE stack are "competing" with each other. From what you've stated: EJB3 + JPA clearly belong to JEE stack, on the other hand SpringMVC is obviously from Spring universe + spring boot is obviously in a Spring camp.

Now, web.xml is kind of a bootstrap point for regular spring application (excluding spring boot of course). So, in general you should specify a web listener that will load up the spring. When you've tagged a spring boot in the question everything has mixed up. In two words, spring boot indeed alows to configure everything with annotation but it still "assumes" you're using spring under the hood.

Regarding the resources, If you are working with DAO layer, you should define beans for those, but bottom line they will be managed by spring then. But in this case there is no need for EJB. Of course you can still use JPA out of spring DAO (people tend to use Hibernate directly IMO this day if they really need ORM, and Hibernate implements JPA these days) if you wish, but in any case its again will be used by spring.

On the other hand if you need a JEE stack I doubt spring boot can really fit you. JEE stack is a kind of "all-in-one" bundle which is supported by various application servers, and spring from this point of view is "take parts and combine by yourself" solution. So for spring project you can use tomcat/jetty which are not by any means fully compliant JEE servers. BTW this is exactly what spring boot does.

So I think for the sake of the project you should decide in which camp do you want to be, JEE or Spring. Both technologies look appealing these days, each of them has its benefits/drawbacks, but bottom line it boils down to:

• Spring is more flexible and innovative, you get changes faster
• Spring is more complicated to bootstrap (although if there are seasoned developers familiar with spring, it should not be an issue)
• JEE is standardized

Answer 2

Use Spring Boot - no need for xml there. Spring Boot embeds Tomcat (or optionally Jetty), and so does not support EJB.

I'd rewrite the EJB' 's functionality as a "plain old Java" class, using spring features where needed.

For the external config file, Spring has several ways of providing configuration options at runtime / external to the deployment, so no need for JNDI.