如何优雅地加载一个properties配置文件

来源：互联网发布：黄金交易软件排名编辑：程序博客网时间：2024/05/01 06:56

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().);    }}

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