读取配置文件的工具类实现

版权声明：转载请标明出处，否则会依法追究其责任 https://blog.csdn.net/qq_41204714/article/details/82632434

/**
 * 读取配置文件的工具类
 * 
 */
public class ConfigManager {
	// 第一步：构建私有的静态的实例
	private static ConfigManager configManager;
	private static Properties properties;

	// 第二步：构造函数私有化
	private ConfigManager() {
		String configFile = "db.properties";
		properties = new Properties();
		InputStream in = ConfigManager.class.getClassLoader()
				.getResourceAsStream(configFile);
		try {
			properties.load(in);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	// 第三步：公开一个方法，返回单一实例
	public static ConfigManager getInstance() {
		if (configManager == null) {
			configManager = new ConfigManager();
		}
		return configManager;
	}
	
	/**
	 * 根据key返回value
	 * @param key
	 * @return
	 */
	public String getString(String key) {
		return properties.getProperty(key);
	}

}