CODEWITHSUNDEEP
javaspring
bmw0128
bmw0128

Reputation: 13698

How can I force instantiation of all referenced beans during Spring start-up?

My applicationContext.xml:

<bean id="studentService" class="com.coe.StudentService">
    <property name="studentProfile" ref="studentProfile" />
</bean>

<bean id="studentProfile" class="com.coe.student.StudentProfile">

</bean>

My web.xml:

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>

My classes:

StudentService{
private StudentProfile studentProfile;
//has appropriate getters/setters

}

StudentProfile{
private String name;
//has getter/setter

}

i have a jsp that calls studentService.studentProfile.name, and the error says that studentProfile is null

My assumption is that when the server starts up, Spring instantiates all objects as requested, so when the StudentService is called, would not Spring also set StudentProfile?

Upvotes: 0

Views: 1070

Answers (3)

toolkit
toolkit

Reputation: 50237

Normally with Spring and a web-app, you would have a DispatcherServlet and a bunch of controllers, that pass onto JSP views. These controllers would be managed by Spring.

If you want to go direct to a JSP without using DispatcherServlet, then you need some way to make the first injection into your pages (ContextLoaderListener doesn't do this). That is, you must explicitly lookup the initial bean using JSP initialization code such as

[Disclaimer: not tested]

<%@ page import="org.springframework.web.context.support.WebApplicationContextUtils" %>
<%!
    private StudentService studentService;

    public void jspInit() {
        studentService = (StudentService) WebApplicationContextUtils.
            getRequiredWebApplicationContext(getServletContext()).
                getBean("studentService");                  
    }
%>

Upvotes: 2

Tim
Tim

Reputation: 20732

Not really an answer to your question, but a possible solution to your problem, if you're willing to work with annotations instead:

Web.xml

<!-- Spring -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>spring.xml</param-value>
</context-param>

Spring.xml

<context:component-scan base-package="com.coe" />

Java code

@Service
StudentService{
@Autowired
private StudentProfile studentProfile; }

@Repository//???
StudentProfile{
private String name;}

That said I have a little trouble understanding why StudentProfile would be a bean (assuming every student has a profile) and StudentService would have reference to a single StudentProfile, but that might just be your terminology.. (Or my lack of understanding thereof)

Upvotes: 0

user130532
user130532

Reputation:

perhaps your name property is the null item. try setting a value 

<property name="name" value="my value"/>

Upvotes: 1

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