Getters/Setters for java.util.properties

Question

I want display properties in HTML/XML via jsp. Like as:

${MyClass.properties.propertieOne}

I created extended class of properties, MProperties, but how can I create getters in that class for my properties?

BR Kolesar

Answer 1

You can use store(Writer writer, String comments) method in Properties class. Write your properties to a StringWriter and use String from it to print on the HTML.

Answer 2

${yourObject.properties.propertyOne} works. Properties extends Hashtable implement Map and ${map.key} gives you the value under that key. But you are not supposed to use a setter from a JSP, so this is only for display purposes.

But you can't access it directly from a static field. You have to add it to some context - request or application. For example, in a ServletContextListener.contextInitialized(..) :

servletContext.addAttribute("yourProperties", MyClass.properties);

(then you'd have to map the <listener> in web.xml, of course)

Answer 3

If you extended Properties , you probably know exactly which fields you want to have. In that case, it would seem to be better to just a create a POJO (simple object) with those fields and the appropriate getters (and setters and/or constructor as you wish). If you somehow need the dynamic-ness (?) of Properties , ignore this answer.

Answer 4

you can create class to handle your properties with constructor like

private Properties props = null;

    private MyProperties() throws IOException {

        FileInputStream propFile = new FileInputStream(FULL_PATH);
        props = new Properties(System.getProperties());
        props.load(propFile);

        RegistryManager rm = RegistryManager.singleton();
        rm.addRegistry("MyProperty", this);
    }

public static MyProperties Singelton() {
        synchronized (MyProperties.class) {
            if (theInstance == null) {
                try {
                    theInstance = new MyProperties();
                } catch (IOException e) {
                    throw new MissingResourceException("Unable to load property file \"" + FULL_PATH + "\"", MyProperties.class.getName(),
                            PROPERTIES_FILENAME);
                }
            }
        }
        return theInstance;
    }

and than get properties by one method like

public static String getProperty(String propertyName) {
        String value = Singelton().props.getProperty(propertyName);
        if (value == null) {
            LOGGER.warning("propertyName (" + propertyName + ") not found in property file (" + FULL_PATH + ")");
        }

        return value;
    }

finally in code you can call only

String desiredProperty = MyProperties.getProperty("propertyKey");

some code is missing and some you maybe wont need but you should get the idea if this is what you wanted to do...