Spring配置文件中條件判斷標簽

<bean id="propertyConfigurer"
	class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
	<property name="locations">
		<array>
			<value>classpath:/settings.properties</value>
		</array>
	</property>
</bean>

 

 

 

 

<constructor-arg name="password" value="#{'${redis.password}'?:null}"></constructor-arg>
<!--表示當redis.password不為空時，那么返回redis.password，否則返回null -->
<!-- 或者可以如下表示那么含義就更清晰了-->
<constructor-arg name="password" value="#{'${redis.password}'!=''?'${redis.password}':null}"></constructor-arg>

setting.properties:

 

redis.masterName=mymaster
redis.password=
redis.number=0

 

 

 

注意：一定要給${redis.password}顯式加上單引號，否則它就會被解析為bean。從而報錯：

 

Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Field or property 'foobared' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext'