经过修改的读取配置文件PROPERTIES的小工具，对象尽量创建一次

package com.opzoon.app.airchina.util;

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

public class ConfigUtil {
	private final static Properties prop = new Properties();
	private static ConfigUtil instance; 

	private ConfigUtil() {
	     InputStream is=null;
	     is=this.getClass().getClassLoader().getResourceAsStream("conf"+File.separator+"config.properties");
		 if (null!=is) {
		    	try {
		    		prop.load(is);
		    	} catch (IOException e) {
		    		e.printStackTrace(System.err);
				} catch (Exception ex) {
				 ex.printStackTrace(System.err);
				}
		    	finally {
		    		try {
		    			if(null!=is) {
		    				is.close();
		    				is=null;
		    			}
		    		}catch(IOException e) {
		    			e.printStackTrace();
		    		}
		    	}
		 } else {
		     System.out.println("无法找到配置文件：");
	     }//end if -else
	}

	 public String getProperty(String key) {	

		String value;
		if (prop.containsKey(key)) {
		 value = (String) prop.get(key);
		 } else {
		 value = "";
		 }
		 return value;
	 }

	 public static ConfigUtil getInstance(){
		 if(instance == null){
			 instance = new ConfigUtil();
			 System.out.println("---- getInstance new is called");
		 }
		 return instance;
	 }

	 public static void main(String args[]){
		 System.out.println("xxxxxLOCAL_PATH="+new ConfigUtil().getProperty("LDAP_PATH"));
		 System.out.println("xxxxxLOCAL_PATH="+new ConfigUtil().getProperty("FTP_PATH"));
	 }

	 public static String getStaticProperty(String key) {
		 return getInstance().getProperty(key);
	 }
}