【愚公系列】2022年01月 Java教学课程 58-Properties集合

public class PropertiesDemo01 {
    public static void main(String[] args) {
        //创建集合对象
//        Properties<String,String> prop = new Properties<String,String>(); //错误
        Properties prop = new Properties();

        //存储元素
        prop.put("itheima001", "佟丽娅");
        prop.put("itheima002", "赵丽颖");
        prop.put("itheima003", "刘诗诗");

        //遍历集合
        Set<Object> keySet = prop.keySet();
        for (Object key : keySet) {
            Object value = prop.get(key);
            System.out.println(key + "," + value);
        }
    }
}

public class PropertiesDemo02 {
    public static void main(String[] args) {
        //创建集合对象
        Properties prop = new Properties();

        //Object setProperty(String key, String value)：设置集合的键和值，都是String类型
        prop.setProperty("itheima001", "佟丽娅");
        prop.setProperty("itheima002", "赵丽颖");
        prop.setProperty("itheima003", "刘诗诗");

        //String getProperty(String key)：使用此属性列表中指定的键搜索属性
//        System.out.println(prop.getProperty("itheima001"));
//        System.out.println(prop.getProperty("itheima0011"));

//        System.out.println(prop);

        //Set<String> stringPropertyNames()：从该属性列表中返回一个不可修改的键集，其中键及其对应的值是字符串
        Set<String> names = prop.stringPropertyNames();
        for (String key : names) {
//            System.out.println(key);
            String value = prop.getProperty(key);
            System.out.println(key + "," + value);
        }
    }
}

public class PropertiesDemo03 {
    public static void main(String[] args) throws IOException {
        //把集合中的数据保存到文件
//        myStore();

        //把文件中的数据加载到集合
        myLoad();

    }

    private static void myLoad() throws IOException {
        Properties prop = new Properties();

        //void load(Reader reader)：
        FileReader fr = new FileReader("myOtherStream\\fw.txt");
        prop.load(fr);
        fr.close();

        System.out.println(prop);
    }

    private static void myStore() throws IOException {
        Properties prop = new Properties();

        prop.setProperty("itheima001","佟丽娅");
        prop.setProperty("itheima002","赵丽颖");
        prop.setProperty("itheima003","刘诗诗");

        //void store(Writer writer, String comments)：
        FileWriter fw = new FileWriter("myOtherStream\\fw.txt");
        prop.store(fw,null);
        fw.close();
    }
}

public class Student implements Serializable {
    private static final long serialVersionUID = 1L;

    private String name;
    private int age;

    public Student() {
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

public class Test {

    public static void main(String[] args) throws IOException {
      	//1.创建Properties集合,将本地文件中的数据加载到集合中
        Properties prop = new Properties();
        FileReader fr = new FileReader("prop.properties");
        prop.load(fr);
        fr.close();
		//2.获取集合中的键值对数据,封装到学生对象中
        String name = prop.getProperty("name");
        int age = Integer.parseInt(prop.getProperty("age"));
        Student s = new Student(name,age);
		//3.创建序列化流对象,将学生对象序列化到本地文件中
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("a.txt"));
        oos.writeObject(s);
        oos.close();
    }
}