java - 无法解析字符串值中的占位符

Question

我正在尝试使用 .properties 文件中的属性，但它似乎不起作用。

这是我的代码:

@Service("ServiceFTP")
@Transactional
public class ServiceFTPImpl implements ServiceFTP {

@Value("${project.ftp.adresse}")
private String adresse;

@Value("${project.ftp.login}")
private String compte;

@Value("${project.ftp.password}")
private String motDePasse;

@Value("${project.ftp.root}")
private String ROOT;

[...]

}

此类使用 @Value 注释来获取属性。它也被声明为 Spring Service 并链接到我的 infraContext.xml 文件:

<?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-3.2.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">

<context:property-placeholder location="classpath:context-core.properties"/>

[...]

</beans>

使用 context:property-placeholder，我将此文件链接到我的 context-core.properties 文件:

project.ftp.adresse = localhost
project.ftp.login = anonymous
project.ftp.password =
project.ftp.root = /anonymous/

这确实有道理，对吧？

但是当我尝试启动我的项目时，Tomcat 抛出了这个异常:

    ERROR [context.ContextLoader.initWebApplicationContext()] Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'ServiceFTP': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String project.sins.service.impl.ServiceFTPImpl.adresse; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'project.ftp.adresse' in string value "${project.ftp.adresse}"
    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$1.getObject(AbstractBeanFactory.java:294)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:925)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:472)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:388)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:293)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:111)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4887)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5381)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:657)
    at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1636)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String project.sins.service.impl.ServiceFTPImpl.adresse; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'project.ftp.adresse' in string value "${project.ftp.adresse}"
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:513)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:92)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
    ... 27 more
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'project.ftp.adresse' in string value "${project.ftp.adresse}"
    at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:173)
    at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:125)
    at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:151)
    at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:142)
    at org.springframework.context.support.PropertySourcesPlaceholderConfigurer$2.resolveStringValue(PropertySourcesPlaceholderConfigurer.java:169)
    at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:748)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:740)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:730)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:485)
    ... 29 more

或者，简而言之:java.lang.IllegalArgumentException: Could not resolve placeholder 'project.ftp.adresse' in string value "${project.ftp.adresse}"

编辑:

这是我的 web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         id="sins" version="2.5">

    <display-name>Project</display-name>

    <listener>
        <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
    </listener>

    <context-param>
        <param-name>log4jExposeWebAppRoot</param-name>
        <param-value>false</param-value>
    </context-param>

    <filter>
        <filter-name>ExpiresFilter</filter-name>
        <filter-class>org.apache.catalina.filters.ExpiresFilter</filter-class>
        <init-param>
            <param-name>ExpiresByType text/html</param-name>
            <param-value>now plus 0 seconds</param-value>
        </init-param>
        <init-param>
            <param-name>ExpiresByType application/json</param-name>
            <param-value>now plus 0 seconds</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>ExpiresFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>

    <filter>
        <filter-name>EncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>EncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
        <filter-class>
            org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter
        </filter-class>
    </filter>

    <filter-mapping>
        <filter-name>Spring OpenEntityManagerInViewFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <listener>
        <listener-class>org.apache.struts2.tiles.StrutsTilesListener</listener-class>
    </listener>

    <context-param>
        <param-name>
            org.apache.tiles.impl.BasicTilesContainer.DEFINITIONS_CONFIG
        </param-name>
        <param-value>
            /WEB-INF/tiles/user.xml
        </param-value>
    </context-param>

    <resource-ref>
        <res-ref-name>jdbc/si_nsg</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>

    <session-config>
        <session-timeout>60</session-timeout>
    </session-config>

</web-app>

我的 infraContext.xml 被导入到另一个名为 applicationContext.xml 的 .xml 文件中:

<?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:jee="http://www.springframework.org/schema/jee"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.1.xsd">

    <bean class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
        <property name="environment">
            <bean class="org.springframework.web.context.support.StandardServletEnvironment"/>
        </property>
    </bean>

    <import resource="classpath:securityContext.xml"/>

    [...]
    <import resource="classpath:project/sins/persistenceContext.xml"/>

    <import resource="classpath:project/sins/infraContext.xml"/>

</beans>

我显然遗漏了一些东西，但我不知道是什么。

如果您需要更多详细信息，请告诉我，因为这是我在这里的第一个问题，我会尽快回答:)。

Answer 1

在您的配置中，您有 2 个 PropertySourcesPlaceholderConfigurer 实例。

applicationContext.xml

<bean class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
    <property name="environment">
        <bean class="org.springframework.web.context.support.StandardServletEnvironment"/>
    </property>
</bean>

infraContext.xml

<context:property-placeholder location="classpath:context-core.properties"/>

默认情况下，PlaceholderConfigurer 会快速失败，因此如果无法解析占位符，它将引发异常。 applicationContext.xml 文件中的实例没有属性，因此在所有占位符上都会失败。

解决方案:从 applicationContext.xml 中删除一个，因为它不会添加任何内容，只会破坏某些内容。