java--Proreties

Prorerties

/* 
 * Properties,内存与文件信息交互
 * 表示了一个持久的属性集
 * 
 * 构造方法：
 * 	Properties()
 * 
 * 
 */


 //简单使用  创建，添加，遍历，
 	private static void method() {
		// 创建属性列表对象
		Properties prop = new Properties();
		//添加映射关系
		prop.put("czbk001","zhangs");
		prop.put("czbk002","lis");
		prop.put("czbk003","wangs");
		
		//遍历
		//获取所有的key，根据key获取value
		Set<java.lang.Object> keys = prop.keySet();
		for(java.lang.Object key:keys)
		{
			java.lang.Object value = prop.get(key);
			System.out.println(key+"="+value);
		}
		System.out.println("------");
		Set<Entry<java.lang.Object, java.lang.Object>> entrys = prop.entrySet();
		for(Entry<java.lang.Object, java.lang.Object> entry:entrys)
		{
			java.lang.Object value = entry.getValue();
			java.lang.Object key = entry.getKey();
			System.out.println(key + "=" + value);
		}




//与IO流的结合
//保存到文件（只能接收打印流）
private static void method2() throws FileNotFoundException {
	// void list(PrintWriter out)
	// void list(PrintStream out)
	//创建属性列表
	Properties prop = new Properties();
	//添加映射关系
	prop.setProperty("CZBK001","zhangs");
	prop.setProperty("CZBK002", "wangs");
	prop.setProperty("CZBK003", "lis");
	
	//创建打印流对象
	PrintWriter out = new PrintWriter("d.txt");
	
	//void list(PrintWriter out)
	prop.list(out);
	//释放资源
	out.close();
}



//从文件读取到prop
private static void method3() throws FileNotFoundException, IOException {
	// void load(Reader reader)
	
	//创建属性列表对象
	Properties prop = new Properties();
	//创建一个输入流对象
	FileReader fr = new FileReader("d.txt");
	
	//void load(Reader reader)
	prop.load(fr);
	
	//释放资源
	fr.close();
	
	System.out.println(prop);
}



//保存到文件(任意)
//void store(Writer writer, String comments)	
private static void method4() throws IOException {
	// 创建属性列表对象
	Properties prop = new Properties();
	// 添加映射关系
	prop.setProperty("CZBK001","zhangs");
	prop.setProperty("CZBK002", "wangs");
	prop.setProperty("CZBK003", "lis");
	// 创建输出流对象
	FileWriter fw = new FileWriter("e.txt");
	
	//void store(Writer writer, String comments)
	prop.store(fw, "comments message");
	
	//释放资源
	fw.close();
}



//编码问题
//如果写入文件时出现了乱码，可以尝试修改编码

OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("b.txt"), "UTF-8");
String s = "你好鸭";
osw.write(s);
osw.close();