将Properties集合中的键值对写入到文件中（遍历）

package com.day16.test1;

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Properties;
import java.util.Set;

public class Test2 {
	public static void main(String[] args) {
		// 属性集合类不支持泛型
		Properties properties = new Properties();

		// 添加键值对
		properties.setProperty("name", "程静静");
		properties.setProperty("age", "20");
		properties.setProperty("gender", "man");

		PrintWriter printWriter = null;

		try {
			// 创建自动刷新字符打印流对象
			printWriter = new PrintWriter(new FileWriter("jjj.txt"), true);

			// 拿到properties中所有的key
			Set keys = properties.keySet();

			// 遍历所有的key
			for (Object object : keys) {
				// 将object强转成String
				String key = (String) object;

				// 通过key获取到相对应的值
				String value = properties.getProperty(key);

				// key和值写入到文件中
				printWriter.println(key + "=" + value);
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (printWriter != null) {
				printWriter.close();
			}
		}
	}
}