J2EE里读取资源文件

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class Configment {

	private static Configment config=null;
	/**
	 * cannot be extend
	 */
	private  Configment(){
		
	}
	/**
	 * get the instance
	 * @return
	 */
	synchronized public static Configment getInstance() {
		if(config==null){
			return new Configment();
		}else
			return config;
	}
	/**
	 * get the value of key
	 * @param key
	 * @return
	 */
	synchronized public String getValue(String key){
		Properties properties=new Properties();
		String value="";
		try {
// 此处路径很重要..
//不然在发布到tomcat下之后，获取路径会默认弄到 tomcat/bin 
			InputStream in=getClass().getResourceAsStream("/config.properties");
			properties.load(in);
			value=(String)properties.get(key);
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return value;
	} 
	
	public static void main(String[] args) {
		Configment config=Configment.getInstance();
		String ip=config.getValue("udpIp");
		System.out.println(ip);

	}

}