简述Properties 持久的属性集

// 根据key读取value    public void readValue(String filePath, String key) {        Properties props = new Properties();        InputStream in = new BufferedInputStream(new FileInputStream(filePath));  //Thread.currentThread().getContextClassLoader().getResourceAsStream("eop.properties");        props.load(in); // 从输入流中读取属性列表(键和元素对)      String value = props.getProperty(key);    }      // 读取properties的全部信息    public static void readProperties(String filePath) {      Properties props = new Properties();      InputStream in = new BufferedInputStream(new FileInputStream(filePath));        props.load(in);        Enumeration en = props.propertyNames();      while (en.hasMoreElements()) {        String key = (String) en.nextElement();        String value = props.getProperty(key);    　　}    }