CODEWITHSUNDEEP
javaspringautowired
SBel
SBel

Reputation: 3359

Simple autowire="byName" doesn't work

I have a POJO with a field message:

package com.packt.lifecycle;

public class HelloWorld {

    private String message;

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
}

In my app context XML I have 2 bean definitions:

<bean id="helloWorld" class="com.packt.lifecycle.HelloWorld" autowire="byName">
</bean>

<bean name="message" class="java.lang.String" >
   <constructor-arg value="auto wired1" />
</bean>

However, the autowiring by name for some reason doesn't work. The following code displays null:

AbstractApplicationContext  context = new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld world = (HelloWorld) context.getBean("helloWorld");
System.out.println(world.getMessage());

Upvotes: 0

Views: 308

Answers (3)

Roman C
Roman C

Reputation: 1

Autowire doesn't work because the property is not configured in Spring. Put the annotation on the field or method to let the Spring know that this property needs autowiring.

@Component
public class HelloWorld {

    private String message;

    public String getMessage() {
        return message;
    }

    @Autowired
    public void setMessage(String message) {
        System.out.println(message);
        this.message = message;
    }
}

To make annotations work you need something like

<!--<context:annotation-config/>-->
<context:component-scan base-package="com.packt.lifecycle"/>

Upvotes: 0

ring bearer
ring bearer

Reputation: 20783

You can not autowire strings like that. Check out the exceptions for auto-wiring.

I think auto-wiring of constant primitives are discouraged so that they are created like property values - that will force you to externalize your constants to a property file which sounds more appropriate.

Rather define your message in a properties file as :

message.key=Hello World

Then load your properties with a PropertyConfigurer and then autowire constant properties as :

@Value("${message.key}")
private String message;

or provide a default value (hard coded) as

@Value("${useDefault:Hello World}")
private String message;

Upvotes: 2

coderz
coderz

Reputation: 4999

Just add your property within your bean definition:

<bean id="helloWorld" class="com.packt.lifecycle.HelloWorld" autowire="byName">
  <property name="message" value="auto wired1" />
</bean>

Upvotes: -1

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