Configuring Beans in the Spring IoC Container

Author: eduard.hildebrandt

Spring is a powerful IoC container to manage components. To utilize the container components, you have to configure your beans. In this post I will show you how to configure you beans using XML. You probably already know how to configure beans using setter injection:

package com.mycompany.myproject;
public class MyService {
	private String myValue;
	public void setMyValue(String myValue) {
		this.myValue = myValue;
	}
}

<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">
    <bean name="myService" class="com.mycompany.myproject.MyService">
        <property name="myValue">
            <value>someValue</value>
        </property>
    </bean>
</beans>

Or using shortcuts:

<bean name="myService" class="com.mycompany.myproject.MyService" >
    <property name="myValue" value="someValue"/>
</bean>

But here are some configuration options you probably haven't used yet:
Spring allows you to use constructor injection:

package com.mycompany.myproject;
public class MyService {
	private String myValue;
	public MyService(String myValue) {
		super();
		this.myValue = myValue;
	}
}

<bean name="myService" class="com.mycompany.myproject.MyService" >
    <constructor-arg>
        <value>someValue</value>
    </constructor-arg>
</bean>

Or using shortcuts:

<bean name="myService" class="com.mycompany.myproject.MyService" >
    <constructor-arg value="someValue" />
</bean>

An other convenient shortcut to define properties is by using the p schema to define bean properties:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean name="myService" class="com.mycompany.myproject.MyService" p:myValue="someValue" />
</beans>

You can use lists as properties:

package com.mycompany.myproject;
import java.util.List;
public class MyService {
	private List