CODEWITHSUNDEEP
javaspring
black panda
black panda

Reputation: 2991

How do I inject property from one bean into another in Spring 3.0?

In Spring 3.0.2, I am trying to inject the property of Bean A into another Bean B, but the Spring EL isn't working.

Bean A is being created manually in Java. Bean B is created through XML.

In this case Bean A is Potato and Bean B is Baby (both in package springinit).

Bean A (Potato):

public class Potato {
   String potatoType;

   public String getPotatoType() { return potatoType; }

   public void setPotatoType(String potatoType) { this.potatoType = potatoType; }

   @Override
   public String toString() {
       return "Potato{" + "potatoType=" + potatoType + '}';
   }
}

Bean B (Baby):

public class Baby {

    private String name;
    private Potato potatoThing;

    public String getName() { return name; }

    public void setName(String name) { this.name = name; }

    public Potato getPotatoThing() { return potatoThing; }

    public void setPotatoThing(Potato p) { this.potatoThing = p; }

    @Override
    public String toString() {
        return "Baby{" + "name=" + name +
                ", potatoThing=" + potatoThing + '}';
    }
}

In my Main class, I create a Potato and use it in the XML when trying to make a Baby

package springinit;

import static org.springframework.beans.factory.support.BeanDefinitionBuilder.genericBeanDefinition;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.support.GenericApplicationContext;
import org.springframework.core.io.ClassPathResource;

public class Main {

    public static void main(String[] args) {
        GenericApplicationContext ctx= new GenericApplicationContext();

        // define java-based spring bean
        ctx.registerBeanDefinition("myPotato", 
                genericBeanDefinition(Potato.class)
                    .addPropertyValue("potatoType", "spudzz")
                    .getBeanDefinition());

        // read in XML-bean
        XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(ctx);
        xmlReader.loadBeanDefinitions(
                new ClassPathResource("/resources/spring_init.xml"));

        // print out results
        System.out.format(
                "Baby: %s%n%n" +
                "Potato: %s%n",
                ctx.getBean(Baby.class),
                ctx.getBean(Potato.class)
        );
    }
}

Here's my spring_init.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">

  <bean id="myBaby" class="springinit.Baby" depends-on="myPotato">
      <property name="name" value="#{myPotato.potatoType}" />
      <property name="potatoThing">
          <ref bean="myPotato" />
          </property>
  </bean>
</beans>

When I run main, I get this output:

Baby: Baby{name=#{myPotato.potatoType}, potatoThing=Potato{potatoType=spudzz}}

Potato: Potato{potatoType=spudzz}

I want the baby's name to be "spudzz", which is a property of myPotato. Why won't spring inject this value into the baby?

Thank you for reading. I hope it was clear enough.

Upvotes: 4

Views: 3397

Answers (1)

axtavt
axtavt

Reputation: 242786

Perhaps you need to call ctx.refresh() before getting beans.

From javadoc:

Typical usage is to register a variety of bean definitions via the BeanDefinitionRegistry interface and then call AbstractApplicationContext.refresh() to initialize those beans with application context semantics (handling ApplicationContextAware, auto-detecting BeanFactoryPostProcessors, etc).

Upvotes: 5

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