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

huangapple
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英文:

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

问题

I have a class with lombok @RequiredArgsConstructor:

  1. @RequiredArgsConstructor
  2. @Service
  3. public class Test{
  5. private final String str;
  6. private String str5;
  8. // more code
  10. }

In non-spring boot we provide in xml as:

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

如何在Spring Boot中实现相同的功能，可能通过application.properties，但如何进行注入？

英文:

I have a class with lombok @RequiredArgsConstructor:

  1. @RequiredArgsConstructor
  2. @Service
  3. public class Test{
  5. private final String str;
  6. private String str5;
  8. // more code
  10. }

In non-spring boot we provide in xml as:

  1. &lt;bean id=&quot;Test&quot; class=&quot;com.abc.Test&quot;&gt;
  2. 		&lt;constructor-arg index=&quot;0&quot; value=&quot;${xyz}&quot;/&gt;
  3. 	&lt;/bean&gt;

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

答案1

得分: 1

在这种情况下，我认为最好的做法要么是注释字段：

  1. @Service
  2. public class Test{
  4.     @Value("${xyz}")
  5.     private String str;
  7.     private String str5;
  9.     // 更多的代码
  10. }

或者显式地定义带有注释参数的构造函数：

  1. @Service
  2. public class Test{
  4.     private final String str;
  6.     private String str5;
  8.     public Test(@Value("${xyz}") String str) {
  9.         this.str = str;
  10.     }
  12.     // 更多的代码
  13. }

如果您有其他 final 字段，您可以结合使用 Lombok 构造函数生成和字段注释，就像在 https://stackoverflow.com/questions/52321988 中所提到的那样：

  1. @RequiredArgsConstructor
  2. @Service
  3. public class Test{
  5.     @Value("${xyz}")
  6.     private String str;
  8.     private final String str5;
  10.     // 更多的代码
  11. }
英文:

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

  1. @Service
  2. public class Test{
  4.     @Value(&quot;${xyz}&quot;)
  5.     private String str;
  7.     private String str5;
  9.     // more code
  10. }

or defining explicitly the constructor with an annotated parameter:

  1. @Service
  2. public class Test{
  4.     private final String str;
  6.     private String str5;
  8.     public Test(@Value(&quot;${xyz}&quot;) String str) {
  9.         this.str = str;
  10.     }
  11.     // more code
  12. }

And if you have other final fields you can combine lombok constructor generation with field annotation like this as noted in https://stackoverflow.com/questions/52321988

  1. @RequiredArgsConstructor
  2. @Service
  3. public class Test{
  5.     @Value(&quot;${xyz}&quot;)
  6.     private String str;
  8.     private final String str5;
  10.     // more code
  11. }

答案2

得分: 0

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.

  1. //Test.java
  2. package com.abc;
  4. import lombok.RequiredArgsConstructor;
  5. import lombok.ToString;
  7. @RequiredArgsConstructor
  8. @ToString
  9. public class Test {
  11. private final String str;
  12. private String str5;
  14. }
  1. //DemoApplication.java
  2. package com.abc;
  4. import org.springframework.beans.factory.annotation.Value;
  5. import org.springframework.boot.SpringApplication;
  6. import org.springframework.boot.autoconfigure.SpringBootApplication;
  7. import org.springframework.context.annotation.Bean;
  9. @SpringBootApplication
  10. public class DemoApplication {
  12. 	public static void main(String[] args) {
  13. 		SpringApplication.run(DemoApplication.class, args);
  14. 	}
  16. 	@Bean
  17. 	Test buildTest(@Value("${xyz}") String value) {
  18. 		return new Test(value);
  19. 	}
  21. }

note: @SpringBootApplication implies @Configuration

  1. //DemoApplicationTests.java
  2. package com.abc;
  4. import org.junit.jupiter.api.Test;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.boot.test.context.SpringBootTest;
  8. @SpringBootTest
  9. class DemoApplicationTests {
  11. 	@Autowired
  12. 	com.abc.Test test;
  14. 	@Test
  15. 	void contextLoads() {
  16. 		System.out.println(test);
  17. 	}
  19. }
  1. #application.properties
  2. xyz=print me

Result:

  1. Test(str=print me, str5=null)
英文:

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.

  1. //Test.java
  2. package com.abc;
  4. import lombok.RequiredArgsConstructor;
  5. import lombok.ToString;
  7. @RequiredArgsConstructor
  8. @ToString
  9. public class Test {
  11. private final String str;
  12. private String str5;
  14. }
  1. //DemoApplication.java
  2. package com.abc;
  4. import org.springframework.beans.factory.annotation.Value;
  5. import org.springframework.boot.SpringApplication;
  6. import org.springframework.boot.autoconfigure.SpringBootApplication;
  7. import org.springframework.context.annotation.Bean;
  9. @SpringBootApplication
  10. public class DemoApplication {
  12. 	public static void main(String[] args) {
  13. 		SpringApplication.run(DemoApplication.class, args);
  14. 	}
  16. 	@Bean
  17. 	Test buildTest(@Value(&quot;${xyz}&quot;) String value) {
  18. 		return new Test(value);
  19. 	}
  21. }

note: @SpringBootApplication implies @Configuration

  1. //DemoApplicationTests.java
  2. package com.abc;
  4. import org.junit.jupiter.api.Test;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.boot.test.context.SpringBootTest;
  8. @SpringBootTest
  9. class DemoApplicationTests {
  11. 	@Autowired
  12. 	com.abc.Test test;
  14. 	@Test
  15. 	void contextLoads() {
  16. 		System.out.println(test);
  17. 	}
  19. }
  1. #application.properties
  2. xyz=print me

Result:

  1. Test(str=print me, str5=null)

huangapple
  • 本文由 发表于 2020年8月13日 00:05:19
  • 转载请务必保留本文链接：https://go.coder-hub.com/63380477.html
  • constructor-injection
  • java
  • lombok
  • spring-boot
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