Dinesh on Java

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://davproductionDB:3306
jdbc.username=root
jdbc.password=root

<bean class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" id="dataSource">
  <property name="driverClassName" value="${jdbc.driverClassName}">
  <property name="url" value="${jdbc.url}">
  <property name="username" value="${jdbc.username}">
  <property name="password" value="${jdbc.password}">
</property></property></property></property></bean>

XmlBeanFactory factory = new XmlBeanFactory(new FileSystemResource("spring.xml"));
PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();
cfg.setLocation(new FileSystemResource("databaseConfig.properties"));
cfg.postProcessBeanFactory(factory);

ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");

Triangle.java

package com.dineshonjava.sdnext.beanFactoryPP.tutorial;

public class Triangle
{
 private Point pointA;
 private Point pointB;
 private Point pointC;
 /**
  * @param pointA the pointA to set
  */
 public void setPointA(Point pointA) {
  this.pointA = pointA;
 }

 /**
  * @param pointB the pointB to set
  */
 public void setPointB(Point pointB) {
  this.pointB = pointB;
 }

 /**
  * @param pointC the pointC to set
  */
 public void setPointC(Point pointC) {
  this.pointC = pointC;
 }

 public void draw()
 {
System.out.println("PointA is ("+pointA.getX()+", "+pointA.getY()+")");
System.out.println("PointB is ("+pointB.getX()+", "+pointB.getY()+")");
System.out.println("PointC is ("+pointC.getX()+", "+pointC.getY()+")");
 }
}

Point.java

package com.dineshonjava.sdnext.beanFactoryPP.tutorial;

public class Point
{
 private int x;
 private int y;
 /**
  * @return the x
  */
 public int getX() {
  return x;
 }
 /**
  * @param x the x to set
  */
 public void setX(int x) {
  this.x = x;
 }
 /**
  * @return the y
  */
 public int getY() {
  return y;
 }
 /**
  * @param y the y to set
  */
 public void setY(int y) {
  this.y = y;
 }
}

spring.xml

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p" xmlns:>
In the above configuration file, bean id "pointC" have the two properties x and y the value of these two properties read from the property file (shape.properties)as given below

shape.properties
pointC.x=20
pointC.y=0

Now define a class which implement the BeanFactoryPostProcessor interface for the config the bean factory at the time of initialization with given property file value.


 BeanFactoryPPDemo.java
package com.dineshonjava.sdnext.beanFactoryPP.tutorial;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.core.io.FileSystemResource;

public class BeanFactoryPPDemo implements BeanFactoryPostProcessor  
{
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
 {
 PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();  
 cfg.setLocation(new FileSystemResource("shape.properties"));  
 cfg.postProcessBeanFactory(beanFactory); 
 System.out.println("Bean factory post processor is initialized");
 }
}

If every thing is Ok then run the following main application file and see the console.

DrawingApp.java
package com.dineshonjava.sdnext.beanFactoryPP.tutorial;

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

/**
 * @author Dinesh Rajput
 *
 */
public class DrawingApp 
{
 /**
  * @param args
  */
 public static void main(String[] args) 
 {
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
Triangle triangle = (Triangle) context.getBean("triangle");
triangle.draw();
 }

}


Output:
Jul 5, 2012 12:43:27 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@ab50cd: startup date [Thu Jul 05 00:43:27 IST 2012]; root of context hierarchy
Jul 5, 2012 12:43:27 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [spring.xml]
Jul 5, 2012 12:43:27 AM org.springframework.core.io.support.PropertiesLoaderSupport loadProperties
INFO: Loading properties file from file [F:my workspacespring16BeanFactoryPPDemoshape.properties]
Bean factory post processor is initialized
Jul 5, 2012 12:43:27 AM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@14c1103: defining beans [triangle,pointA,pointB,pointC,com.dineshonjava.sdnext.beanFactoryPP.tutorial.BeanFactoryPPDemo#0]; root of factory hierarchy

PointA is (0, 0)

PointB is (-20, 0)

PointC is (20, 0)