访问Spring配置文件中的属性值(Access property values inside Spring config file)

访问Spring配置文件中的属性值(Access property values inside Spring config file)

我在WEB-INF/local.db.properties有一个简单的属性文件：

db.driverClassName=org.postgresql.Driver db.url=jdbc:postgresql://localhost:5432/db_name db.username=postgres db.password=password

我试图在我的Spring配置文件中访问这些属性（到最后）：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
         http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
         http://www.springframework.org/schema/util
         http://www.springframework.org/schema/util/spring-util-3.1.xsd
         http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context-3.0.xsd">

 <context:component-scan base-package="controllers" />

 <mvc:annotation-driven/>
 <mvc:default-servlet-handler/>

 <bean id="tilesConfigurer" class="org.springframework.web.servlet.view.tiles3.TilesConfigurer">
     <property name="definitions">
         <list>
             <value>/WEB-INF/tiles-config.xml</value>
         </list>
     </property>
 </bean>

 <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
     <property name="viewClass" value="org.springframework.web.servlet.view.tiles3.TilesView"/>
 </bean>

 <util:properties id="dbProperties" location="WEB-INF/local.db.properties" />
 <bean id="dbDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
     <property name="driverClassName" value="${db.driverClassName}" /> <!--ERROR -->
     <property name="url" value="${db.url}" />
     <property name="username" value="${db.username}" />
     <property name="password" value="${db.password}" />
 </bean>
</beans>
 
 错误是Could not load JDBC driver class [${db.driverClassName}] 。 错误对我来说非常清楚 - 它不是试图查找它只是使用原始字符串的属性。 
 
 我该如何解决？ 
 
 这是一个Maven 3，Spring 4，Postgresql项目。 
I have a simple properties file at WEB-INF/local.db.properties:
 
db.driverClassName=org.postgresql.Driver
db.url=jdbc:postgresql://localhost:5432/db_name
db.username=postgres
db.password=password
 
I am trying to access these properties inside of my Spring configuration file (towards the end): 
 
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
         http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
         http://www.springframework.org/schema/util
         http://www.springframework.org/schema/util/spring-util-3.1.xsd
         http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context-3.0.xsd">

 <context:component-scan base-package="controllers" />

 <mvc:annotation-driven/>
 <mvc:default-servlet-handler/>

 <bean id="tilesConfigurer" class="org.springframework.web.servlet.view.tiles3.TilesConfigurer">
     <property name="definitions">
         <list>
             <value>/WEB-INF/tiles-config.xml</value>
         </list>
     </property>
 </bean>

 <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
     <property name="viewClass" value="org.springframework.web.servlet.view.tiles3.TilesView"/>
 </bean>

 <util:properties id="dbProperties" location="WEB-INF/local.db.properties" />
 <bean id="dbDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
     <property name="driverClassName" value="${db.driverClassName}" /> <!--ERROR -->
     <property name="url" value="${db.url}" />
     <property name="username" value="${db.username}" />
     <property name="password" value="${db.password}" />
 </bean>
</beans>
 
The error is Could not load JDBC driver class [${db.driverClassName}]. The error is pretty clear to me - it is not trying to look up the property it is just using the raw string. 
 
How do I fix this?
 
This is a Maven 3, Spring 4, Postgresql project.
                
最满意答案
                
                    
                        
 您没有在Spring配置中加载属性文件。 添加此行： 
 
<context:property-placeholder location="classpath:/WEB-INF/local.db.properties"/>
 
 要么 
 
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/local.db.properties"/>
</bean>
 
 如果您有多个属性文件，请更改以上配置： 
 
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <!-- locations, not location, check the S at the end -->
    <property name="locations">
        <list>
            <value>
                /WEB-INF/local.db.properties
            </value>
            <value>
                <!-- Path of another properties file -->
            </value>
        </list>
    </property>
</bean>
 
 更多信息： PropertySourcesPlaceholderConfigurer 
You're not loading the properties file in Spring configuration. Add this line:
 
<context:property-placeholder location="classpath:/WEB-INF/local.db.properties"/>
 
or
 
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/local.db.properties"/>
</bean>
 
If you have several properties file, change the above configuration for:
 
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <!-- locations, not location, check the S at the end -->
    <property name="locations">
        <list>
            <value>
                /WEB-INF/local.db.properties
            </value>
            <value>
                <!-- Path of another properties file -->
            </value>
        </list>
    </property>
</bean>
 
More info: PropertySourcesPlaceholderConfigurer