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java - Error with private field using @Autowired

问题描述

I've an error using Spring when changing the visibility of a variable.

I've this code (which works fine)

@Component
public class TennisCoach implements Coach {

    @Autowired
    public FortuneService fortuneService;

    @Override
    public String getDailyWorkout() {
        return "Do tennis stuff!";
    }

    @Override
    public String getFortune() {
        return fortuneService.getFortune();
    }

}

(FortunateService is an interface, and I've a class HappyFortunateService which implements it, and I've it annotated with @Component as well)

with this main method

public static void main(String[] args) {
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
    Coach annotatedCoach = context.getBean("tennisCoach", Coach.class);

    System.out.println(annotatedCoach.getDailyWorkout());
    System.out.println(annotatedCoach.getFortune());

    context.close();

}

And when I turn on the TennisCoach class the fortunateService variable visibility to private, I get this error:

org.springframework.context.support.AbstractApplicationContext refresh
WARNING: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tennisCoach': Injection of autowired dependencies failed; nested exception is java.lang.reflect.InaccessibleObjectException: Unable to make field private me.davichete.springproject.FortuneService me.davichete.springproject.TennisCoach.fortuneService accessible: module spring_project does not "opens me.davichete.springproject" to module spring.core
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tennisCoach': Injection of autowired dependencies failed; nested exception is java.lang.reflect.InaccessibleObjectException: Unable to make field private me.davichete.springproject.FortuneService me.davichete.springproject.TennisCoach.fortuneService accessible: module spring_project does not "opens me.davichete.springproject" to module spring.core
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:405)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1420)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:897)
    at spring.context@5.2.9.RELEASE/org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879)
    at spring.context@5.2.9.RELEASE/org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551)
    at spring.context@5.2.9.RELEASE/org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:144)
    at spring.context@5.2.9.RELEASE/org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:85)
    at spring_project/me.davichete.springproject.HelloSpringApp.main(HelloSpringApp.java:8)
Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field private me.davichete.springproject.FortuneService me.davichete.springproject.TennisCoach.fortuneService accessible: module spring_project does not "opens me.davichete.springproject" to module spring.core
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:361)
    at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:301)
    at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:177)
    at java.base/java.lang.reflect.Field.setAccessible(Field.java:171)
    at spring.core@5.2.9.RELEASE/org.springframework.util.ReflectionUtils.makeAccessible(ReflectionUtils.java:782)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:667)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130)
    at spring.beans@5.2.9.RELEASE/org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
    ... 13 more

Does anybody know why? Spring version: 5.2.9 Java SE15

EDIT: My project is set up adding the Spring JAR files to the ModulePath, I'm not using Maven.

My module-info.java looks like this:

module spring_project {
    requires spring.context;
    requires java.logging;
    requires spring.beans;

    exports me.davichete.springproject;
}

EDIT: I tested it deleting the module-info.java, and now it seems to work, probably related to the answer of @Menelaos

标签： javaspringautowired

解决方案

Try adding a constructor and making your field final

If you are using Lambok, you could do the following:

  1. Set @RequiredArgsConstructor on your class - which will generate a constructor with params for all final variables.
  2. Change your field to final, and get rid of @Autowired.

Spring will take care of injecting the value for final fields.

If you are not using lambok, you need to add the constructor by hand.

See the constructor injection example @ https://stackoverflow.com/a/55473346/1688441

Java 9 Modules

Have a look also at the following: How to solve InaccessibleObjectException ("Unable to make {member} accessible: module {A} does not 'opens {package}' to {B}") on Java 9?

Your error is due to limitations and changes in Java 9.

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