I am new Springs. In Bean tag I found factory-method and factory-bean Attributes. What is the difference between factory-method and factory-bean?
I am using factory-method to call my getInstance static method to create singleton object.
What is factory-bean used for?
For given replies, What I understood was
Factory-method is used for calling a static method to create object in same bean class.
Factory-bean is used for creating a object based on factory design pattern.
Ex:- I am asking a EggPlant object from VegetableFactory (Which will return vegetable object which was asked)class by passing my vegetable name(EggPlant in this case).
Please correct if I am wrong?
factory-method: represents the factory method that will be invoked to inject the bean.
factory-bean: represents the reference of the bean by which factory method will be invoked. It is used if factory method is non-static.
Printable.java
package com.javatpoint;
public interface Printable {
void print();
}
A.java
package com.javatpoint;
public class A implements Printable{
@Override
public void print() {
System.out.println("hello a");
}
}
B.java
package com.javatpoint;
public class B implements Printable{
@Override
public void print() {
System.out.println("hello b");
}
}
PrintableFactory.java
package com.javatpoint;
public class PrintableFactory {
//non-static factory method
public Printable getPrintable(){
return new A();//return any one instance, either A or B
}
}
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="pfactory" class="com.javatpoint.PrintableFactory"></bean>
<bean id="p" class="com.javatpoint.Printable" factory-method="getPrintable"
factory-bean="pfactory"></bean>
</beans>
Notice that public Printable getPrintable()
of PrintableFactory.java
is a non-static method. Generally if we want access/call method or other resources of the a class we have to create it's instance. Similarly in that we created it bean. using bean's reference variable pfactory
we are calling the factory method getPrintable
.