Is there any syntax like : #{systemProperties['environment_variable_name']} to get the system variable?

Question

Does using #{systemProperties['environment']} in the applicationcontext.xml file of Spring return the value associated with environment?

Or is there any way to ge the system variable value in the spring applicationcontext.xml file.

Plio

Are you talking about system properties or environment variables? Those are two different things, you know... – Eberle

Answer 1

When I remember right, then there is a difference between:

You can access the system properties in different ways:

• #{systemProperties['databaseName']}
• #{systemProperties.databaseName}
• ${databaseName} //$ instead of # !!

With #{systemProperties['databaseName']} you have access to system-system-properties.

With #{systemProperties.databaseName} you have access to the system properties readed for example from the command line (-DdatabaseName="testDB").

With ${databaseName} you have access the the properties from the properties files loaded and provided for example by the PropertyPlaceholderConfigurer and to the system prooperties too

@Value("#{systemProperties['java.version']}")
private String javaVersionMap;

//Dont know how
//@Value("#{systemProperties.javav.version}")
//private String javaVersionDirect;

@Value("${java.version}")
private String javaVersionProp;

---

//-DcmdParam=helloWorld
@Value("#{systemProperties['cmdParam']}")
private String cmdParamMap;

@Value("#{systemProperties.cmdParam}")
private String cmdParamDirect;

@Value("${cmdParam}")
private String cmdParamProp

You can use all of them in a @Value annotation or the config.xml files (<property name="databaseName" value="#{systemProperties.databaseName}"/>)

Haemophilia

Does anybody know the right names for this two different kind of system properties (the system provided and the command line provides ones)? – Haemophilia

no such thing exists. The command line version sets "real" system properties: download.oracle.com/javase/6/docs/technotes/tools/windows/… . Such a difference does only exist in Maven : System Properties (command line) vs Project Properties (pom.xml) – Eberle

@Sean Patrick Floyd: I have tested it and you are right (It seams that my records were wrong). -- I have corrected the answer – Haemophilia

Answer 2

One way to do this kind of thing is to use a PropertyPlaceholderConfigurer which can be configured to use the system properties.

I also noticed that the Spring 3.1 M1 blog entry talks about new stuff for accessing configuration information from "the environment". Of course, that is only a milestone ... not a production-ready release.

Petuu