How to get JAVA_OPTS value in jsp

I am trying to get JAVA_OPTS value defined in catalina.bat in a jsp file. Can someone tell me how to do that.

For Example: My JAVA_OPTS definition in catalina.bat is like

JAVA_OPS= -DMyProjectHome=D:\Pro开发者_如何学编程jects

I want to have the value of MyProjectHome at run time in jsp file so I am trying to do is ${MyProjectHome} but it is doing nothing.

Or is there a way I can define JAVA_OPTS value in

Please help me out achieving my functionality.

thanks.

what you pass to a JVM with -Dfoo=bar is called a system property. You can get their value using System.getProperty(). There is no standard tag or JSP EL syntax to get them, though, so you'll have to use scriptlet or implement a custom tag.

Wrap it in a class which extends a Map.

public class SystemProperties extends HashMap<String, String> {

    @Override
    public String get(Object name) {
        return System.getProperty(name != null ? name.toString() : null);
    }

}

Declare it as follows in JSP.

<jsp:useBean id="systemProperties" class="com.example.SystemProperties" scope="application" />

Then you can just treat it as Map in EL.

${systemProperties['MyProjectHome']}

or

${systemProperties.MyProjectHome}

Those are Java system properties. You can access it via the Java function

System.getProperty("MyProjectHome");

There might be a better way to do it in JSP but that will work.