Calling Static Method Using SpEL

Spring 3 provides powerful Expression Language which can be used to wire values into beans properties by calling static method of any bean using SpEL's T() operator.

Lets take an example to demonstrate how SpEL is used to wire value by calling static  method.

MyClass.java: The MyClass class contains property named "random" which is of String type.

package spel.callingstaticmethodsusingSpEL;

public class MyClass
{
private String random;

public void setRandom(String random) {
this.random = random;
}
public String getRandom() {
return random;
}
}

spring-beans.xml: We will see how to use static method random() of java.util.Math class to wire random property of the MyClass class using T() operator of Spring expression Language. This operator takes fully qualified class name.

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean id="myClass" class="spel.callingstaticmethodsusingSpEL.MyClass">
<property name="random" value="#{T(java.lang.Math).random()}"/>
</bean>

</beans>

AppMain.java: This class loads the context configuration file spring-beans-list.xml from the class path.

package spel.callingstaticmethodsusingSpEL;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import spel.callingstaticmethodsusingSpEL.MyClass;

public class AppMain{
public static void main( String[] args ){
ApplicationContext appContext = new ClassPathXmlApplicationContext(new String[] {"spel\\callingstaticmethodsusingSpEL\\spring-beans-list.xml"});
MyClass myObj = (MyClass)appContext.getBean("myClass");

System.out.println("-------------------------------------");
System.out.println("Random Value: "+myObj.getRandom());
System.out.println("-------------------------------------");
}
}

The output of the above program will be as below:

-------------------------------------
Random Value: 0.6188206590561351
-------------------------------------

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