IO流，Properties基本功能和遍历

import java.util.Enumeration;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;

public class PropertiesDemo {
    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.put("zhangsan", "23");
        properties.put("lisi", "25");
        properties.put("wangwu", "21");
        properties.put("zhaoliu", "27");
        Set<String> names = properties.stringPropertyNames();
        //使用高级for遍历
        for(String name : names) {
            String value = properties.getProperty(name);
            System.out.println(name + " = " + value);
        }
        //使用迭代器遍历
        Iterator<String> iterable = names.iterator();
        while(iterable.hasNext()){
            String key = iterable.next();
            String value = properties.getProperty(key);
            System.out.println(key +" = " + value);
        }
        //使用枚举遍历
        Enumeration<String> enumeration = (Enumeration<String>)properties.propertyNames();
        while(enumeration.hasMoreElements()) {
            String key = enumeration.nextElement();
            String value = properties.getProperty(key);
            System.out.println(key + " = " + value);
        }
    }
}