IOC : Constructor Injection in Different Styles

Bean.java:

package com.lnn.ioc;

public class Bean {

      private String text;

      private double number;

      public Bean(String text, double number) {

            this.text = text;

            this.number = number;

      }

      public String getText() {

            return text;

      }

      public double getNumber() {

            return number;

      }

}

constructor.xml:

<beans xmlns="http://www.springframework.org/schema/beans"

      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

      xsi:schemaLocation="http://www.springframework.org/schema/beans

      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

      <!-- providing the values as per order -->

      <bean id="bean1" class="com.lnn.ioc.Bean">

            <constructor-arg value="text" />

            <constructor-arg value="4.5" />

      </bean>

      <!-- providing the values as by using name -->

      <bean id="bean2" class="com.lnn.ioc.Bean">

            <constructor-arg name="text" value="super text" />

            <constructor-arg name="number" value="4.5" />

      </bean>

      <!-- providing the values as by using type -->

      <bean id="bean3" class="com.lnn.ioc.Bean">

            <constructor-arg type="java.lang.String" value="super text" />

            <constructor-arg type="double" value="4.5" />

      </bean>

      <!-- providing the values as by using index -->

      <bean id="bean4" class="com.lnn.ioc.Bean">

            <constructor-arg index="0" value="super text" />

            <constructor-arg index="1" value="4.5" />

      </bean>

      <!-- providing the values as by using type not in order (not suggested) -->

      <bean id="bean5" class="com.lnn.ioc.Bean">

            <constructor-arg type="double" value="4.5" />

            <constructor-arg type="java.lang.String" value="super text" />      

      </bean>

</beans>

Test.java:

package com.lnn.ioc;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

      public static void main(String[] args) {

            ApplicationContext context = new ClassPathXmlApplicationContext("ioc/constructor.xml");

            Bean bean1 = context.getBean("bean1", Bean.class);

            System.out.println(bean1.getText());

            System.out.println(bean1.getNumber());

            Bean bean2 = context.getBean("bean2", Bean.class);

            System.out.println(bean2.getText());

            System.out.println(bean2.getNumber());

            Bean bean3 = context.getBean("bean3", Bean.class);

            System.out.println(bean3.getText());

            System.out.println(bean3.getNumber());

            Bean bean4 = context.getBean("bean4", Bean.class);

            System.out.println(bean4.getText());

            System.out.println(bean4.getNumber());

            Bean bean5 = context.getBean("bean5", Bean.class);

            System.out.println(bean5.getText());

            System.out.println(bean5.getNumber());

      }

}