Utility class for reading and writing Properties files

PropertiesUtil.java

package com.XXXX.XXX.common.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

@VersionId("@(#) PropertiesUtil.java [@@/main/ens_java_template/1]>")
public class PropertiesUtil extends EnsBaseObject {

    private final static Log log = LogFactory.getLog(PropertiesUtil.class);

    /** Singleton instance */
    private static PropertiesUtil _instance;

    private PropertiesUtil() {
        super();
    }

    /** Singleton factory method - lazy load */
    public static synchronized PropertiesUtil instance() {
        if (_instance == null)
            _instance = new PropertiesUtil();

        return _instance;
    }

    /**
     * Reads a properties (key=value) file into a java.util.Properties object.
     * 
     * @param filename
     * @return
     * @throws FileNotFoundException
     * @throws IOException
     */
    public Properties readPropertiesFromFile(String filename)
            throws FileNotFoundException, IOException {
        Properties p = null;
        FileReader fr = null;

        try {
            p = new Properties();
            fr = new FileReader(filename);
            p.load(fr);
        } finally {
            fr.close();
        }
        return p;
    }

    /**
     * Creates a properties file (key=value), filename, given a
     * java.util.Properties object
     * 
     * @param filename
     * @param properties
     * @throws IOException
     */
    public void writePropertiesToFile(String filename, Properties properties)
            throws IOException {
        FileWriter fw = null;

        try {
            fw = new FileWriter(filename);
            properties.store(fw, "Properties file created on "
                    + new java.util.Date().toString());
        } finally {
            fw.close();
        }

    }

}