java 如何在spring中使用java枚举作为bean
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How to use java enum as bean in spring
提问by Betlista
My goal I want to achieve is to inject enum to Spring managed bean.
我想要实现的目标是将枚举注入 Spring 管理的 bean。
I do not want my bean be configured in XML (there no reason to do so except this not-working enum).
我不希望我的 bean 被配置为 XML（除了这个不工作的枚举，没有理由这样做）。
I have simple maven project:
我有一个简单的 Maven 项目：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>net.betlista</groupId>
<artifactId>test.spring.enum-injection</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>3.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.5.4</version>
</dependency>
<!-- testing -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>${junit.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>3.1.3.RELEASE</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<junit.version>4.11</junit.version>
</properties>
</project>
I created simple test
我创建了简单的测试
import net.betlista.spring.enum_injection.EnumInjectionComponent;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestClass {
@Autowired
EnumInjectionComponent component;
@Test
public void test() {
Assert.assertNotNull(component.roundingMode);
}
}
and my bean is
我的豆子是
package net.betlista.spring.enum_injection;
import java.math.RoundingMode;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class EnumInjectionComponent {
@Autowired
public RoundingMode roundingMode;
}
When I'm trying to run my test Ipm getting
当我试图运行我的测试 Ipm 时
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:157)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:109)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:321)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:211)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runReflectiveCall(SpringJUnit4ClassRunner.java:288)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:290)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
">
<context:spring-configured />
<context:annotation-config />
<context:component-scan base-package="net.betlista"/>
<bean id="rounding" class="java.math.RoundingMode" factory-method="valueOf">
<constructor-arg value="UP" />
</bean>
</beans>
0(ParentRunner.java:53)
at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:229)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'enumInjectionComponent': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: public java.math.RoundingMode net.betlista.spring.enum_injection.EnumInjectionComponent.roundingMode; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.math.RoundingMode] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:605)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:925)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:472)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:103)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:1)
at org.springframework.test.context.support.DelegatingSmartContextLoader.loadContext(DelegatingSmartContextLoader.java:228)
at org.springframework.test.context.TestContext.loadApplicationContext(TestContext.java:124)
at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:148)
... 24 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: public java.math.RoundingMode net.betlista.spring.enum_injection.EnumInjectionComponent.roundingMode; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.math.RoundingMode] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:513)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:92)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
... 39 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.math.RoundingMode] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:948)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:817)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:731)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:485)
... 41 more
But in log I can see:
但在日志中我可以看到：
INFO: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@236527f: defining beans [org.springframework.context.config.internalBeanConfigurerAspect,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,enumInjectionComponent,rounding,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
信息：销毁 org.springframework.beans.factory.support.DefaultListableBeanFactory@236527f 中的单例：定义 bean [org.springframework.context.config.internalBeanConfigurerAspect,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,enumInjectionComponent,rounding,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; 工厂层次结构的根
So I have rounding bean in context.
所以我在上下文中有舍入豆。
What I missed?
我错过了什么？
edit: I just found, the problem is with Spring version 3.1.x only, in 3.2.x it works, any workaround available?
编辑：我刚刚发现，问题仅在于 Spring 3.1.x 版，在 3.2.x 中它可以工作，有什么可用的解决方法吗？
edit2: here is definition of beans
编辑2：这是bean的定义
@Value("#{roundingModes[0]}")
public RoundingMode roundingMode;
edit3:
编辑3：
as workaround I used Dev Blanked's workaround to specify the list, and use @Value in my bean as
作为解决方法，我使用 Dev Blanked 的解决方法来指定列表，并在我的 bean 中使用 @Value 作为
<util:list id="roundingModes" value-type="java.math.RoundingMode">
<value>UP</value>
</util:list>
if there is a better (nicer) solution I'd like to see it ;-)
如果有更好（更好）的解决方案，我想看看;-)
采纳答案by Dev Blanked
It should be possible to provide the bare enum name and specify the value-type. below is an example where the rounding mode has been injected to a list. should be the same for a property as well.
应该可以提供裸枚举名称并指定值类型。下面是将舍入模式注入列表的示例。属性也应该相同。
@Override
public void afterPropertiesSet() throws Exception {
roundingMode = RoundingMode.valueOf(roundingModeName);
}
回答by Betlista
Another approach one can use is to specify UP as String and in bean implement InitializingBean interfaceand create the enum in afterPropertiesSet()from that String.
可以使用的另一种方法是将 UP 指定为 String 并在 bean 中实现InitializingBean 接口并afterPropertiesSet()从该 String创建枚举。
