getting a handle to the application context - spring

Question

I am trying t learn various technologies - want to do some UI stuff using HTML5 with Jquery
In the UI I am making a call to a RESTFUL webservice ( Jersey ) which generates JSON output
In my webservice - I had stubbed the data that was supposed to come from the database ( mysql )
Now I want to learn Spring JDBC template ( and not use plain JDBC )
So my question is about using spring ( only spring jdbc and not spring mvc ) in a web application which hosts my RESTFUL webservice
I want to use spring jdbc template - so have written a spring xml file where I am creating the necessary configurations
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="....."
xsi:schemaLocation="....">
<bean id="examDAO" class="com.examscripts.mockexam.repository.ExamRepositoryImpl">
<property name="ds" ref="ds" />
</bean>
<bean id="ds" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost/mockexam" />
<property name="username" value="xxx" />
<property name="password" value="yyy" />
</bean>
To load these in I added the following in web.xml:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
on tomcat startup I can see that the file is loaded :
Loading XML bean definitions from class path resource ....
Now my question is in my service layer where I need to communciate with DAO layer ( jdbc ) - do have to create the actual bean using something like this :
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring.xml");
// instantiate our spring dao object from the application context
ExamRepositoryImpl impl= (ExamRepositoryImpl)ctx.getBean("examDAO");
I am completely new to spring and googling seems to always show spring mvc web apps or standalone spring examples - my case is a web app minus spring mvc but using spring jdbc template
any pointers ?

Answer 1

Loading XML bean definitions from class path resource ....
You're on the right track. Spring is loading your XML file (when you deploy the app) and instantiating the beans that you declared. Crank up the logging for org.springframework to get more details.
Now my question is in my service layer where I need to communciate
with DAO layer ( jdbc ) - do have to create the actual bean using
something like this :
No, definitely not. The entire purpose of using a dependency injection framework like Spring is to avoid writing code like this.
Declare a setter in your service class that takes the DAO as an argument.
public void setExamDAO(ExamDao examDao) {
this.examDao = examDao;
}
Add a new XML bean definition for your service class in your XML file and create a new <property> that wires in the DAO:
<bean id="yourservice" class="com.foo.YourServiceClass">
<property name="examDao" ref="examDAO"/>
</bean>