JAVA读取PROPERTIES文件方式一

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 配置文件读取工具
 */
public class ConfigurableConstants
{

    protected static final String PROPERTIES_PATH = "config.properties";

    protected static Log logger = LogFactory.getLog(ConfigurableConstants.class);
    protected static Properties p = new Properties();
    static
    {
        init(PROPERTIES_PATH);
    }

    /**
     * 静态读入属性文件到Properties p变量中
     */
    protected static void init(String propertyFileName)
    {
        InputStream in =  null;
        try
        {
            // class.getClassLoader()获得该class文件加载的web应用的目录，如WEB-INF/classes/就是根目录
            // getResourceAsStream(relativeFilePath):定位该文件且获得它的输出流
            in = ConfigurableConstants.class.getClassLoader().getResourceAsStream(propertyFileName);
            BufferedReader bf = null;
            if (in != null)
                // load输出流到Properties对象中
                // 因为字节流是无法读取中文的，所以采取reader把inputStream转换成reader用字符流来读取中文。
                bf = new BufferedReader(new InputStreamReader(in));
            p.load(bf);
        }
        catch (IOException e)
        {
            logger.error("load " + propertyFileName + " into Constants error!");
        }
        finally
        {
            if (in != null)
            {
                try
                {
                    in.close();
                }
                catch (IOException e)
                {
                    logger.error("close " + propertyFileName + " error!");
                }
            }
        }
    }

    /**
     * 封装了Properties类的getProperty函数,使p变量对子类透明.
     *
     * @param key
     *            property key.
     * @param defaultValue
     *            当使用property key在properties中取不到值时的默认值.
     */
    public static String getProperty(String key, String defaultValue)
    {
        return p.getProperty(key, defaultValue).trim();
    }

}