1

希望问题是不言自明的

ClassA.java

@Component
@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class ClassA implements InterB {
    private static int counter=0;

    private int objectid = 0;
    @Autowired
    InterA abcd;

    public ClassA() {
        super();
        this.objectid = ++counter;
    }

    @Override
    public void dododo() {
        System.out.println("instance number "+objectid++);
        abcd.doit();
    }
}

ClassB.java

@Component
@Conditional(OracleDBEngineCondition.class)
public class ClassB extends DummyParent implements InterA {
    @Autowired
    private Environment env;

    @Override
    public void doit() {
        System.out.println("hoo hoo" +" -- "+env.getProperty("DBENGINE"));
    }

}

ClassC.java

@Component("classc")
public class ClassC implements Runnable {

    @Autowired
    Provider<InterB> classAPrototypeobj;

    public void doFromAbove() {
        InterB cls = (InterB) classAPrototypeobj.get();
        InterB cls1 = (InterB) classAPrototypeobj.get();
        cls.dododo();
        cls1.dododo();
        System.out.println(cls);
        System.out.println(cls1);

    }

    @Override
    public void run() {
        this.doFromAbove();
    }
}

类配置.java

@Configuration
@ComponentScan
public class ClassConfig {
}

主要方法

public static void main(String[] args) {
    ClassC obj;
    try(AbstractApplicationContext appctx = new AnnotationConfigApplicationContext(ClassConfig.class)) {
        obj = (ClassC) appctx.getBean("classc");
    }
    Thread objThread = new Thread(obj);
    objThread.start();
}

更新主要方法（仍然有同样的问题）

public static void main(String[] args) {
    try(AbstractApplicationContext appctx = new AnnotationConfigApplicationContext(ClassConfig.class)) {
        ClassC obj = (ClassC) appctx.getBean("classc");
        Thread objThread = new Thread(obj);
        objThread.start();
    }
}

执行时，这会导致NoSuchBeanDefinitionExceptionbean '环境'

但是当我们在配置类中定义以下内容时，错误消失得无影无踪。这是解决方法（但 Spring 应该自动注入 Environment 我们不应该这样做）。不知道有多少这样的豆子没有注入/@Autowired

@Bean
public Environment environment(ApplicationContext context) {
    return context.getEnvironment();
}

我怀疑这是一个 Spring Framework 错误...不是吗？

堆栈跟踪：

Exception in thread "Thread-1" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'classA': Unsatisfied dependency expressed through field 'abcd'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'classB': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'environment' available
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:325)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.getObject(DefaultListableBeanFactory.java:1630)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory$Jsr330DependencyProvider.get(DefaultListableBeanFactory.java:1699)
    at tpt.verifypoc.ClassC.doFromAbove(ClassC.java:28)
    at tpt.verifypoc.ClassC.run(ClassC.java:39)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'classB': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'environment' available
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
    ... 14 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'environment' available
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:687)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1207)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:284)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$ShortcutDependencyDescriptor.resolveShortcut(AutowiredAnnotationBeanPostProcessor.java:740)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1077)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.resolvedCachedArgument(AutowiredAnnotationBeanPostProcessor.java:548)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.access$200(AutowiredAnnotationBeanPostProcessor.java:117)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:577)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
    ... 25 more

笔记：

  1. 春天：4.3.9.RELEASE
  2. JSR330：javax.inject 版本 1
4

1 回答 1

0

我想说这不是 Spring 中的错误，在您开始使用您正在关闭的对象之前查看您的代码ApplicationContext。或者实际上，您拥有的 try-with-resources 块可以做到这一点。

public static void main(String[] args) {
    ClassC obj;
    try(AbstractApplicationContext appctx = new AnnotationConfigApplicationContext(ClassConfig.class)) {
        obj = (ClassC) appctx.getBean("classc");
    }
    Thread objThread = new Thread(obj);
    objThread.start();
}

基本上是一样的

public static void main(String[] args) {
    ClassC obj;
    AbstractApplicationContext appctx = new AnnotationConfigApplicationContext(ClassConfig.class)) {
        obj = (ClassC) appctx.getBean("classc");

    appctx.close();

    Thread objThread = new Thread(obj);
    objThread.start();
}

ApplicationContext在使用对象之前，您正在关闭。剩下的是一个ClassC带有半支持代理的 instanceof，Provided<ClassB>它需要上下文来查找某些 bean。但是，当您从其下方拉出注册表时，它无法查找这些 bean。

当您关闭时，ApplicationContext您正在关闭您的应用程序。我希望您仍然存在的对象现在无效，因为所属的容器已被销毁。

将代码与 JDBC 代码进行比较。您正在打开一个Connection，关闭连接，然后尝试在关闭的连接上准备一个语句。JDBC 不允许这样做，因为它Connection已关闭，因此无效。

将其与 Microsoft Excel 进行比较，打开它，在工作表中工作，编写宏。关闭 excel 并期望宏仍然可以运行。

于 2017-07-13T12:28:03.443 回答