PropUtil

/**
*
*/
package com.yulong.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Properties;

import org.apache.log4j.Logger;

/**
*
*/
public class PropUtil
{

private final Logger logger = Logger.getLogger(this.getClass());
private static final String DEFAULT_PROPERTY = "application_config.properties";
    
    private String propFile;
    private File configFile;
    private long fileLastModified;
    private Properties props;

   
    public PropUtil()
    {
    this(DEFAULT_PROPERTY);
    }    
    public PropUtil(String propFile)
    {
    this.propFile = propFile;
   
    init();
    }    
    private void init()
    {
        URL url = PropUtil.class.getResource(propFile);
        if (url == null)
        url = PropUtil.class.getClassLoader().getResource(propFile);
        try {
url = new URL(URLDecoder.decode(url.toString(),"UTF-8"));
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (url == null)
url = ClassLoader.getSystemResource(propFile);
//if (url == null)
// throw new IllegalArgumentException("coundn't find resource [" + propFile + "]");

if (url != null)
configFile = new File(url.getFile());  
else
configFile = new File(propFile);

        if (configFile == null || !configFile.exists())
        throw new IllegalArgumentException("coundn't find resource [" + propFile + "]");
      
        fileLastModified = configFile.lastModified();       
if (logger.isDebugEnabled())
logger.debug("properties file is: " + propFile +", last modified time is: "+ fileLastModified);
       
        props = new Properties();
        loadProperty();   
    }
    private void loadProperty()
    {
        try
        {
            props.load(new FileInputStream(configFile));
            fileLastModified = configFile.lastModified();            
        }
        catch (IOException e)
        {           
            throw new RuntimeException(e);
        }
    }

    public String getProperty(String key)
    {       
    return (getProperty(key, ""));
    }
    public String getProperty(String key, String defValue)
    {        
        if (configFile.lastModified() > fileLastModified)
        {
    loadProperty();
   
    if (logger.isDebugEnabled())
    logger.debug("properties file is reload at " + fileLastModified);        
        }
       
        String prop = props.getProperty(key);
       if (prop == null || "".equals(prop))
        prop = defValue;
      
if (logger.isDebugEnabled())
logger.debug("property is: " + prop);    
               
        return (prop);
    }
   
    public synchronized void setProperty(String key, String value)
    {   
    props.setProperty(key, value);
    }

}