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Spring Sweets: Using @Value for Constructor Arguments

· Java Zone

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In Spring we can use the @Value annotation to set property or arguments values based on a SpEL expression. If we want to use the @Value annotation for a constructor argument we must not forget to add the @Autowired annotation on the constructor as well.

// File: sample/Message.groovy
package sample

import org.springframework.beans.factory.annotation.*
import org.springframework.stereotype.*

@Component
class Message {

    final String text

    // Use @Autowired to get @Value to work.
    @Autowired
    Message(
        // Refer to configuration property
        // app.message.text to set value for 
        // constructor argument message.
        @Value('${app.message.text}') final String text) {
        this.text = text
    }

}

Written with Spring 4.1.6.

The Java Zone is brought to you in partnership with ZeroTurnaround. Check out this 8-step guide to see how you can increase your productivity by skipping slow application redeploys and by implementing application profiling, as you code!

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Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

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