What is property resolution order in Spring property placeholder configurer with multiple locations?

Question

Lets say I have a configuration:

    <bean id="batchJobProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>first.properties</value>
            <value>second.properties</value>
        </list>
    </property>
</bean>

first.properties has property "my.url=first.url" second.properties has property "my.url=second.url"

So which value will be injected to the "myUrl" bean? Is there is any defined order of properties resolution?

Answer 1

The javadoc for PropertiesLoaderSupport.setLocation states

Set locations of properties files to be loaded.

Can point to classic properties files or to XML files that follow JDK 1.5's properties XML format.

Note: Properties defined in later files will override properties defined earlier files, in case of overlapping keys. Hence, make sure that the most specific files are the last ones in the given list of locations.

So the value of my.url in second.properties will override the value of my.url in first.properties.

Answer 2

The last one wins.

Assuming we have props1.properties as

prop1=val1

and props2.properties

prop1=val2

and context.xml

<context:annotation-config />
<bean id="batchJobProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>/props1.properties</value>
            <value>/props2.properties</value>
        </list>
    </property>
</bean>
<bean class="test.Test1" /> 

then

public class Test1 {
    @Value("${prop1}")
    String prop1;

    public static void main(String[] args) throws Exception {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("/test1.xml");
        System.out.println(ctx.getBean(Test1.class).prop1);
    }

}

prints

val2

and if we change context as

        <list>
            <value>/props2.properties</value>
            <value>/props1.properties</value>
        </list>

the same test prints

val1