EasyConfig.java

package com.github.walker.easydb.assistant;

import org.apache.log4j.Logger;

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

/**
 * This class loads config infomation.
 *
 * @author HuQingmiao
 */
public class EasyConfig {
    // database connection config file
    public static String CONFIG_FILENAME = "easydb.properties";

    private static Logger log = LogFactory.getLogger(EasyConfig.class);

    // the variable configCache stores the config info
    private static Properties configCache = new Properties();

    static {
        try {
            InputStream is = EasyConfig.class.getClassLoader().getResourceAsStream(CONFIG_FILENAME);
            configCache.load(is);

            // 如果设定了重定向文件, 则装载该文件
            String redirectFile = configCache.getProperty("redirect_file");
            if (redirectFile != null) {
                CONFIG_FILENAME = redirectFile;
                // is.close();
                is = EasyConfig.class.getClassLoader().getResourceAsStream(CONFIG_FILENAME);
                configCache.load(is);
            }

            log.info("Loading the config information from '" + EasyConfig.CONFIG_FILENAME + "'... OK! ");

        } catch (FileNotFoundException e) {
            log.error("Loading the config information from '" + EasyConfig.CONFIG_FILENAME + "'... FAILED! ", e);
        } catch (IOException e) {
            log.error("Loading the config information from '" + EasyConfig.CONFIG_FILENAME + "'... FAILED! ", e);
        }
    }

    private EasyConfig() {
    }

    /**
     * Retrieves the configuration info by the key.
     *
     * @param key
     */
    public static String getProperty(String key) {

        if (configCache.containsKey(key)) {
            return configCache.getProperty(key).trim();
        }
        return null;
    }

}