Reading properties from an XML file using Input Stream?

Question

Currently within my Java Application I have the following Class that I use in order to retrieve values from my properties file (application.properties):

public class MyProperties {
    private static Properties defaultProps = new Properties();
    static {
        try {

            java.io.InputStream in= MyProperties.class.getClassLoader().getResourceAsStream("application.properties");
            defaultProps.load(in);
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static String getProperty(String key) {
        return defaultProps.getProperty(key);
    }
}

An example of instantiating an int using the MyProperties class:

int maxNumberOfPeople = Integer.parseInt(MyProperties.getProperty("maximumPeople"));

I would like to change this class in order to read an XML properties file rather than eg application.Properties.

How can I do so, and still keep the ability to still instantiate values using the MyProperties class?

Answer 1

Read the javadoc for the Properties.loadFromXML(...) method.

Method summary:

Loads all of the properties represented by the XML document on the specified input stream into this properties table.

The Properties javadoc includes the DTD for the XML document (file).

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It would be better to write your loader using a try-with-resources like this:

try (java.io.InputStream in = MyProperties.class.getClassLoader().
            getResourceAsStream("application.properties")) {
    // load properties
} catch (Exception e) {
    e.printStackTrace();
}

Also, it is a bad idea to catch and squash exceptions like that.

1. Don't catch Exception .
2. If the properties failed to load, you most likely want the application to "bail out".

Finally, you probably shouldn't load the properties in a static initializer, because that leaves you with no clean way to deal with any exceptions that might arise.