How to read a properties file in java in the original order

Question

I need to read a properties file and generate a Properties class in Java. I do so by using:

Properties props = new Properties();
props.load(new FileInputStream(args[0]));
for (Enumeration e = props.propertyNames(); e.hasMoreElements();) {
}

However, the properties returned by props.propertyName is not in the order of the original properties file. I understand that Properties are just old fashioned, non-generified Hashtables. I'm looking for a work around. Any idea? Thank you!

Answer 1

Example from www.java2s.com should solve your problem.

import java.util.Enumeration;
import java.util.Properties;
import java.util.Vector;

/**
 * <a href="OrderedProperties.java.html"><b><i>View Source</i></b></a>
 *
 * @author Brian Wing Shun Chan
 *
 */
public class OrderedProperties extends Properties {

    public OrderedProperties() {
        super ();

        _names = new Vector();
    }

    public Enumeration propertyNames() {
        return _names.elements();
    }

    public Object put(Object key, Object value) {
        if (_names.contains(key)) {
            _names.remove(key);
        }

        _names.add(key);

        return super .put(key, value);
    }

    public Object remove(Object key) {
        _names.remove(key);

        return super .remove(key);
    }

    private Vector _names;

}

And your code will change to:

Properties props = new OrderedProperties();
props.load(new FileInputStream(args[0]));
for (Enumeration e = props.propertyNames(); e.hasMoreElements();) {
}