Useful Spring Utilities(API's)

1. Default behaviour of Spring is that , when same names beans are loaded in a single applicationContext , the first bean will
be overridden by the latter.

We had usecase where we required to get an error when multiple beans had the same name.


I have to extend ClassPathXmlApplicationContext and overide this method as it was protected.

@Override
public void setAllowBeanDefinitionOverriding(
boolean allowBeanDefinitionOverriding) {
super.setAllowBeanDefinitionOverriding(allowBeanDefinitionOverriding);
}


ctx.setAllowBeanDefinitionOverriding(false);
ctx.setConfigLocation("classpath*:/META-INF/spring/conf*.xml");
ctx.afterPropertiesSet(); //will initialize the context


2. To get teh number of beans initialized by the application Context.

ctx.getBeanDefinitionCount());


3. To get the resouces read by created ApplicationContext based ona regular Expression.
[This is very handy in an integratde environment to exactlt know the resources ]

I had to extend ClassPathXmlApplicationContext as this method was protected.

@Override
protected Resource[] getConfigResources() {
// TODO Auto-generated method stub
return super.getConfigResources();
}


Resource[] resources = ((ResourcePatternResolver) ctx).getResources("classpath*:/META-INF/spring/conf*.xml");

where ctx is the initialized applicationContext.


4. If we need multiple definitons for <context:property-placeholder/>

Only one context:property-placeholder (the last one defined in the configuration files) will prevail.
You can define two separate PropertyPlaceholderConfigurers and work, only if the second one has a different placeholderPrefix and placeholderSuffix.


< bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" >
< property name="location" value="classpath:/com/foo/2.properties" / >
< property name="placeholderPrefix" value="#[" / >
< property name="placeholdersuffix" value="]" / >
< / bean >

< bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" >
< property name="location" value="classpath:/1.properties" / >
< / bean >


Normal way of replacing is ${property1} and with new prefix and suffix #[]