access properties from spring file in java class

Question

I've been assuming stuff and seeing that now it's not correct. I have the following configuration properties declaration in my spring context :

<bean class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">
        <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
        <property name="searchContextAttributes" value="true" />
        <property name="contextOverride" value="true" />
        <property name="locations">
            <list>
                <value>classpath:/app.properties</value>
            </list>
        </property>
    </bean>

I thought values from app.properties would override my system properties so I would be able to acess them directly in my Java classes like this :

String someThingFromPropertyFile = System.getProperty("nameFromPropertyFile");

And of course I get null pointer exceptions all over the place. Now I'm here to ask how to access your application properties from you application (Java classes part of your application).

Is there a better way than this below (I'm not saying it's bad).

Access properties file programmatically with Spring?

Why not just inject the property where you need it or use the utils? (I'm not sure why you'd think they'd override system properties--they're completely unrelated.) — Dave Newton, Oct 09 '12 at 15:45

score 6 · Accepted Answer · answered Oct 09 '12 at 15:51

In app context :

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

then in java you can do this :

@Value("${cities}")
private String cities;

where the your.properties contains this :

cities = my test string

score 0 · Answer 2 · answered Oct 09 '12 at 16:40

Spring properties do not override System properties. It works the other way. You should be getting all your properties from Spring and not from System.getProperties(). System properties will override Spring properties with the same name. The SYSTEM_PROPERTIES_MODE_OVERRIDE you are setting says that when you get a property value from Spring the System property will win.

You want to set the value to be SYSTEM_PROPERTIES_MODE_FALLBACK. This is the default so you don't actually need to set it.

If you have this in mind, @NimChimpsky has it the correct method for accessing property values:

@Value("${nameFromPropertyFileOrSystemProperty}")
private String someThingFromProperty;

access properties from spring file in java class

2 Answers2