CODEWITHSUNDEEP
javaspringdependency-injectionioc-container
zjor
zjor

Reputation: 1043

Spring injection is not working if bean created manually in xml

I have the following beans:

Bean.java

import lombok.AllArgsConstructor;
import lombok.Data;

@Data
@AllArgsConstructor
public class Bean {

    private String arg;

}

Service.java

import lombok.Getter;
import javax.inject.Inject;

public class Service {

    @Inject @Getter
    private Bean bean;

    private String arg;

    public Service(String arg) {
        this.arg = arg;
    }
}

Here is how I instantiate those things:

test-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd">

   <bean class="com.example.Bean">
          <constructor-arg value="bean param"/>
   </bean>

   <bean class="com.example.Service">
          <constructor-arg value="service param"/>
   </bean>

</beans>

But when I create the context and look what is inside Service instance:

    ApplicationContext context = new ClassPathXmlApplicationContext("test-context.xml");
    System.out.println(context.getBean(Bean.class));
    System.out.println(context.getBean(Service.class).getBean());

the second System.out gives me null.

Why Bean instance didn't get injected?

Upvotes: 0

Views: 1370

Answers (2)

Nath Papadacis
Nath Papadacis

Reputation: 155

I'm not sure about your approach to mixing and matching XML config with annotations, it requires <context:annotation-config/>. I'd say you'd be safer off doing it one way or the other. If you insist on using XML then inject the dependency in the XML definition

<bean id="foo" class="com.example.Bean">
    <constructor-arg value="bean param"/>
</bean>

<bean class="com.example.Service">
    <constructor-arg value="service param"/>
    <property name="bean" ref="foo" />
</bean>

Alternatively do it all with annotations

@Component
public class Bean {
    private String arg;

    public Bean(@Value("{constructorArg}") final String arg) {
        this.arg = arg;
    }
}

@Service
public class Service {

    @Autowired @Getter
    private Bean bean;

    private String arg;

    public Service(@Value("{constructorArg}") String arg) {
        this.arg = arg;
    }
}

Upvotes: 1

zjor
zjor

Reputation: 1043

I've found the reason, I've just forgot <context:annotation-config/> in order to make @Inject annotation to work.

Upvotes: 2

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