Properties集合

Properties集合

Properties:属性集合

特点：

1.存储属性名和属性值

2.属性名和属性值都是字符串类型

3.没有泛型

4.和流有关

eg : 

public class Demo02 {
    public static void main(String[] args) throws Exception {
        //1.创建集合
        Properties properties = new Properties();
        //2。添加数据
        properties.setProperty("username","zhangsan");
        properties.setProperty("age","20");
        System.out.println(properties.toString());
        //3.遍历
        //3.1    keyset
        //3.2    entryset
        //3.3    StringPropertyNames()
        Set<String> pronames = properties.stringPropertyNames();
        for (String pro : pronames) {
            System.out.println(pro+"==="+properties.getProperty(pro));
        }
        //4.和流有关的方法
        //  1.list方法
        //PrintWriter pw = new PrintWriter("g:\\print.txt");
        //properties.list(pw);
        //pw.close();
        //  2.store方法 保存
        //FileOutputStream fos = new FileOutputStream("g:\\store.properties");
        //properties.store(fos,"注释");
        //fos.close();
        //  3.load方法 加载
        Properties properties1 = new Properties();
        FileInputStream fis = new FileInputStream("g:\\store.properties");
        properties1.load(fis);
        fis.close();
        System.out.println(properties1.toString());
    }
}