factory-bean in Spring XML Configuration
March 09, 2023
factory-bean is a property of <bean> element. It works with factory-method property of <bean> element. To understand factory-bean, we need to create a factory class which will have non-static methods to return the bean instance.
In our example, we have two service classes and one factory class. Factory class will return the instance of service class.
Find the steps to work with factory-bean.
1. Create a factory class and use
factory-method attributes to declare factory instance method.
2. Now use
factory-bean and factory-method attribute of bean tag.
3. The
factory-bean attribute will assign factory bean id and factory-method will assign factory method.
Find the XML code.
<bean id="serviceFactory" class="com.concretepage.ServiceFactory" factory-method="createInstance"></bean> <bean id="userService" factory-bean="serviceFactory" factory-method="createUserService"></bean> <bean id="loginService" factory-bean ="serviceFactory" factory-method="createLoginService"></bean>
Complete Example
spring-config.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">
<bean id="serviceFactory" class="com.concretepage.ServiceFactory" factory-method="createInstance">
</bean>
<bean id="userService" factory-bean="serviceFactory" factory-method="createUserService">
</bean>
<bean id="loginService" factory-bean ="serviceFactory" factory-method="createLoginService">
</bean>
</beans>
package com.concretepage;
public class ServiceFactory {
private static UserService userService= new UserService();
private static LoginService loginService= new LoginService();
private static ServiceFactory serviceFactory= new ServiceFactory();
private ServiceFactory(){}
public UserService createUserService(){
return userService;
}
public LoginService createLoginService(){
return loginService;
}
public static ServiceFactory createInstance(){
return serviceFactory;
}
}
package com.concretepage;
public class UserService {
public UserService() {
System.out.println("Initialising UserService.");
}
}
package com.concretepage;
public class LoginService {
public LoginService(){
System.out.println("Initialising LoginService.");
}
}
package com.concretepage;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SpringDemo {
public static void main(String... args) {
ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");
context.getBean("userService");
context.getBean("loginService");
}
}
Initialising UserService. Initialising LoginService.
