lombok @RequiredArgsConstructor how to inject value to the constructor spring boot

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I have a class with lombok @RequiredArgsConstructor:

@RequiredArgsConstructor
@Service
public class Test{

private final String str;
private String str5;

// more code

}

In non-spring boot we provide in xml as:

<bean id="Test" class="com.abc.Test">
        <constructor-arg index="0" value="${xyz}"/>
    </bean>

how to achieve same from spring boot may be via application.properties but how to inject

spring-boot lombok constructor-injection java
2 Answers

The @Service annotation needs to be removed and the bean must be created in a @Configuration class with a @Bean annotated method returning that class type.

//Test.java
package com.abc;

import lombok.RequiredArgsConstructor;
import lombok.ToString;

@RequiredArgsConstructor
@ToString
public class Test {

private final String str;
private String str5;

}

//DemoApplication.java
package com.abc;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Bean
    Test buildTest(@Value("${xyz}") String value) {
        return new Test(value);
    }

}

note: @SpringBootApplication implies @Configuration

//DemoApplicationTests.java
package com.abc;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    com.abc.Test test;

    @Test
    void contextLoads() {
        System.out.println(test);
    }

}

#application.properties
xyz=print me

Result:

Test(str=print me, str5=null)
user_141688160

In this case I think you are better off either annotating the field :

@Service
public class Test{

    @Value("${xyz}")
    private String str;

    private String str5;

    // more code
}

or defining explicitly the constructor with an annotated parameter:

@Service
public class Test{

    private final String str;

    private String str5;

    public Test(@Value("${xyz}") String str) {
        this.str = str;
    }
    // more code
}

And if you have other final fields you can combine lombok constructor generation with field annotation like this as noted in Best practice for @Value fields, Lombok, and Constructor Injection?

@RequiredArgsConstructor
@Service
public class Test{

    @Value("${xyz}")
    private String str;

    private final String str5;

    // more code
}
user_81529180
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