Spring Boot 应用程序上下文干扰单独的 ClassPathXmlApplicationContext

问题描述

因为我必须使用遗留应用程序，所以我想使用来自单独 Spring 上下文的 bean。

我使用这样的 XML bean 定义创建了这个单独的 Spring 上下文：

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="some.different.package"/>

    <bean id="connectionUrlFactory" class="my.ConnectionUrlFactory">
        <property name="dbServer" value="server.url.com"/>
        <property name="dbDatabasename" value="database"/>
        <property name="dbClientName" value="client"/>
    </bean>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="com.sybase.jdbc4.jdbc.SybDriver"/>
        <property name="url" ref="connectionUrlFactory"/>
        <property name="username" value="user"/>
        <property name="password" value="password"/>
    </bean>

</beans>

在我自己的“外部”Spring Boot 应用程序中，我有这样的上下文 @Configuration：

@Configuration
class Configuration {

    private final ApplicationContext applicationContext;

    Configuration() {
        applicationContext = new ClasspathXmlApplicationContext("beans.xml");
    }

    @Bean
    DaoSybaseImpl sybaseDao() {
        return applicationContext.getBean(DaoSybaseImpl.class);
    }

    @Bean
    DataSource sybaseDataSource() {
        return applicationContext.getBean(DataSource.class);
    }

}

但是，当我运行该应用程序时，出现此错误：

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'sybaseDao': Unsatisfied dependency expressed through method 'setDataSource' parameter 0; nested exception is org.springframework.beans.factory.NoUniqueBeanDeFinitionException: No qualifying bean of type 'javax.sql.DataSource' available: expected single matching bean but found 2: postgresDataSource,sybaseDataSource
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.resolveMethodArguments(AutowiredAnnotationBeanPostProcessor.java:768)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:720)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessproperties(AutowiredAnnotationBeanPostProcessor.java:399)
    at org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.populateBean(AbstractAutowireCapablebeanfactory.java:1413)
    at org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.doCreateBean(AbstractAutowireCapablebeanfactory.java:601)
    at org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.createBean(AbstractAutowireCapablebeanfactory.java:524)
    at org.springframework.beans.factory.support.Abstractbeanfactory.lambda$doGetBean$0(Abstractbeanfactory.java:335)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at org.springframework.beans.factory.support.Abstractbeanfactory.doGetBean(Abstractbeanfactory.java:333)
    at org.springframework.beans.factory.support.Abstractbeanfactory.getBean(Abstractbeanfactory.java:208)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListablebeanfactory.doResolveDependency(DefaultListablebeanfactory.java:1380)
    at org.springframework.beans.factory.support.DefaultListablebeanfactory.resolveDependency(DefaultListablebeanfactory.java:1300)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:887)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791)
    ... 125 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDeFinitionException: No qualifying bean of type 'javax.sql.DataSource' available: expected single matching bean but found 2: postgresDataSource,sybaseDataSource
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveNotUnique(DependencyDescriptor.java:220)
    at org.springframework.beans.factory.support.DefaultListablebeanfactory.doResolveDependency(DefaultListablebeanfactory.java:1358)
    at org.springframework.beans.factory.support.DefaultListablebeanfactory.resolveDependency(DefaultListablebeanfactory.java:1300)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.resolveMethodArguments(AutowiredAnnotationBeanPostProcessor.java:760)
    ... 140 more

当我从 sybaseDataSource 中删除 @Configuration 时，错误消失（然后我的应用程序没有启动，因为它缺少 sybaseDataSource）。

似乎遗留 ClasspathXmlApplicationContext 确实知道我的“外部”Spring Boot 上下文。这怎么可能？

解决方法

我现在已经删除了“外部”Spring 应用程序。使用纯 Java 代码，我可以不受干扰地加载其他上下文。