Inheritance in Spring
Inheritance Demo, In the example given below we are going to tell about the inheritance in the Spring framework. By inheritance we mean a way of forming new classes using classes that have already been defined. Here we have created a simple bean and used this bean as a template for creating other beans.
<bean id="parent" class="mybean" >:-Creates a Parent bean which would be used as a template for creating other beans. Here "mybean" is the name of the bean class which would be referred in the xml file with the id "parent".
<bean id="child" class="mybean" parent="parent">:-Creates a child bean which would be inheriting from the parent bean defined above.
parent="parent":-Specify that this bean is inheriting the properties of some other bean.
<bean id="parent" class="mybean" >
<property name="name" value="Roseindia.net"/>
</bean> <bean id="child" class="mybean" parent="parent"> <property name="address" value="Rohini"/> </bean> |
context.xml
<?xml version="1.0" encoding="UTF-8"?>
|
Main.java
This is the file through which we are retrieving the property of the bean defined above. Some of the methods which are used here are as follows:-
XmlBeanFactory factory = new XmlBeanFactory(new ClassPathResource("context.xml")):-This
method creates an instance of the XmlBeanFactory which is used to read bean
definition from an XML document
new ClassPathResource("context.xml"):-Creates a new
ClassPathResource for ClassLoader .Here the context.xml is the file which is to
be loaded.
(bf.getBean("child")):-This method returns an instance of the bean named "child", which is shared or independent, of the given bean name.
(bf.getBean("subchild")):-This method returns an instance of the bean named "subchild", which is shared or independent, of the given bean name.
stringBuilder.append("Bean"):-This is the method of the class string Builder which appends the specified string to this character sequence.
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
public class Main {
public static void main(String[] args) throws Exception {
XmlBeanFactory bf = new XmlBeanFactory(new ClassPathResource("context.xml"));
System.out.println("===============Inheritance demo=================");
System.out.println(bf.getBean("child"));
System.out.println(bf.getBean("subchild"));
}
}
class mybean {
private String name;
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
final StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("Bean");
stringBuilder.append("{name='").append(name).append('\'');
stringBuilder.append(", address=").append(address);
stringBuilder.append('}');
return stringBuilder.toString();
}
}
Output of the program
Nov 25, 2008 3:39:29 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions INFO: Loading XML bean definitions from class path resource [context.xml] ===============Inheritance demo================= Bean{name='Roseindia.net', address=Rohini} Bean{name='Roseindia.net', address=null} BUILD SUCCESSFUL (total time: 1 second) |