如何优雅地加载一个properties配置文件

一、前言许多时候,系统都需要一个配置文件,重复编写这些配置文件读取程序很烦恼，又浪费时间 ，下面给一个通用的方法

二、方法论

好吧！我们用一个简单的单例模式来解决这个问题，一般来说配置文件都是加载一次就够了,最简单的单例模式（实践比空谈好）1、私有静态对象

private static Config cfg = null;

2、构造器私有化

    private Config() {properties = new Properties();InputStream is = null;try {is = Config.class.getResourceAsStream(path);properties.load(is);} catch (Exception exception) {System.out.println("Can't read the properties file. ");} finally {try {if (is != null) {is.close();}} catch (IOException exception) {exception.printStackTrace();}}}

3、公有静态创建方法

    public static Config getInstance() {if (cfg == null) {cfg = new Config();}return cfg;}public static Config getInstance(String path) {path =path;if (cfg == null) {cfg = new Config();}return cfg;}

三、代码

package common.utils;import common.log.Log;import java.io.IOException;import java.io.InputStream;import java.util.Properties;/*** @author chenhaipeng* @version 1.0* @date 2014/12/04 17:25*/public class Config {private Properties properties;private static Config cfg = null;private String path = "/config/config.properties";private final static String ERR_MSG = "从配置文件中不能取得传入参数的返回值：";private Config() {properties = new Properties();InputStream is = null;try {is = Config.class.getResourceAsStream(path);properties.load(is);} catch (Exception exception) {System.out.println("Can't read the properties file. ");} finally {try {if (is != null) {is.close();}} catch (IOException exception) {exception.printStackTrace();}}}public static Config getInstance() {if (cfg == null) {cfg = new Config();}return cfg;}public static Config getInstance(String path) {path =path;if (cfg == null) {cfg = new Config();}return cfg;}/*** Retun a value for certain key.** @param key a certain key define in properties file.* @return value*/public String getValue(String key) {if (!properties.containsKey(key))return null;String value = properties.getProperty(key);if (value == null) {Log.getLogger().error(ERR_MSG + ":" + key);}return value;}public static void main(String args[]) {System.out.println(Config.getInstance("/config/test.properties").getValue("DB.DRIVER"));//		System.out.println(Thread.currentThread().getContextClassLoader().);}}