@Autowired Annotation in Spring Example

In Spring, you can use @Autowired annotation to auto wire bean on the setter method, constructor or a field. Moreover, it can autowired property in a particular bean.

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Note:
The @Autowired annotation is auto wire the bean by matching data type if spring container find more than one beans same data type then it find by name. 

package com.dineshonjava.sdnext.autowiredannotation.tutorial;

import org.springframework.beans.factory.annotation.Autowired;

public class Circle
{ 
 private Point center;
 //using autowired annotation with setter method
 @Autowired
 public void setCenter(Point center) 
 {
           this.center = center;
 }

 public void draw() 
 {
System.out.println("Circle is drawn of center ("+center.getX()+", "+center.getY()+")");
 }
}

package com.dineshonjava.sdnext.autowiredannotation.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;
 }
}

package com.dineshonjava.sdnext.autowiredannotation.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");
Circle circle = (Circle) context.getBean("circle");
circle.draw();
 }
}

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans">
  
<bean class="com.dineshonjava.sdnext.autowiredannotation.tutorial.Circle" id="circle">
</bean>
  
<bean class="com.dineshonjava.sdnext.autowiredannotation.tutorial.Point" id="pointA">
   <property name="x" value="0"></property>
   <property name="y" value="0"></property>
</bean>
  
<bean class="com.dineshonjava.sdnext.autowiredannotation.tutorial.Point" id="pointB">
   <property name="x" value="-20"></property>
   <property name="y" value="0"></property>
</bean>
  
<bean class="com.dineshonjava.sdnext.autowiredannotation.tutorial.Point" id="pointC">
   <property name="x" value="20"></property>
   <property name="y" value="0"></property>
</bean> 
  
<bean class="com.dineshonjava.sdnext.autowiredannotation.tutorial.Point" id="center">
   <property name="x" value="10"></property>
   <property name="y" value="10"></property>
</bean>
  
 <!-- <bean class="org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor"/> -->    
<!-- <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/> -->    
<context:annotation-config></context:annotation-config>
</beans>