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20140818bug

多次使用Spring   placeholder   

报"Could not resolve placeholder"的解决方案

web.xml:

<context-param>        <param-name>contextConfigLocation</param-name>        <param-value>                WEB-INF/config/spring/dao.xml,                 WEB-INF/config/spring/dfs.xml        </param-value></context-param>

如果这两个xml文件中分别有:

<!-- dao.xml --><context:property-placeholder location="WEB-INF/config/db/dbConnect.properties" /><!-- dfs.xml --><context:property-placeholder location="WEB-INF/config/dfs/dfsManager.properties" />

不管是在一个Spring文件还是在多个Spring文件被统一load的情况下,不允许直接写

<context:property-placeholder location="" /><context:property-placeholder location="" /> 

解决方案:

  (1) 在Spring 3.0中,可以写:

<context:property-placeholder location="xxx.properties" ignore-unresolvable="true"/><context:property-placeholder location="yyy.properties" ignore-unresolvable="true"/>

   (2) 在Spring 2.5中,<context:property-placeholder>没有ignore-unresolvable属性,此时可以改用PropertyPlaceholderConfigurer。其实<context:property-placeholder location="xxx.properties" ignore-unresolvable="true" />与下面的配置是等价的

<bean id="随便" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">     <property name="location" value="xxx.properties" />     <property name="ignoreUnresolvablePlaceholders" value="true" /> </bean>

正因为如此,写多个PropertyPlaceholderConfigurer不加ignoreUnresolvablePlaceholders属性也是一样会出"Could not resolve placeholder"。

 虽然两者是的等价的,但估计大家还是喜欢写<context:property-placeholder>多一些,毕竟简单一些嘛。所以如果是Spring 3.0,直接用解决方案(1)再简单不过了;

如果是Spring 2.5,需要费点力气改写成PropertyPlaceholderConfigurer