Java复习之知识点整理（十三）----标准的输入输出流，File类，浏览文件夹和复制文件夹

一、标准的输入流 System.in

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1.类型是InputStream

@Test
	public void tsSystemIn() throws Exception
	{
		InputStream is = System.in;
		InputStreamReader isr = new InputStreamReader(is);
		
		BufferedReader br = new BufferedReader(isr);
		String line = null;
		while((line = br.readLine()) != null){
			if(line.equals("quit")){
				System.exit(-1);
			}
			System.out.println("hello:" + line);
		}	
	}

二、标准的输出流System.out

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1.System.out 的类型是PrintStream， 是OutputStream的子类的子类

@Test
	public void tsSystemOut() throws Exception{
		
		System.setOut(new PrintStream(new FileOutputStream("d:\\a.txt")));
		System.out.println("xxxxxxxxxxxxxxxxxx");
	}

三、File类,对目录或者文件的封装

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1.isDirectory();

2.exists();

3.isFile();

4.mkdir() / mkdirs() : 创建一级 / 多级目录

5.creatNewFile();

6.listFiles();

7.getCanonicalPath() : 标准的，规范的路径

8.getAbsolutePath() : 绝对路径

四、递归输出D盘下的所有文件和文件夹

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@Test
	public void tsScanFiles()
	{
		List<String> fileList = new ArrayList<String>();
		List<String> folderList = new ArrayList<String>();
		scanFiles("D:\\test",fileList,folderList);
		for(String s : fileList)
		{
			System.out.println("file : " + s);
		}
		for(String s : folderList)
		{
			System.out.println("folder : " + s);
		}
	}
	
	
	/**
	 * 浏览指定路径下的所有文件和文件夹
	 * @param desPath
	 * @param fileList
	 * @param folderList
	 */
	public void scanFiles(String desPath , List<String> fileList,List<String> folderList)
	{		
		File file = new File(desPath);
		File [] fs = file.listFiles();
		for(File f0 : fs)
		{
			if(f0.isFile()) /*如果是文件*/
			{
				fileList.add(f0.getAbsolutePath());
			}
			else
			{
				folderList.add(f0.getAbsolutePath());
				scanFiles(f0.getAbsolutePath(),fileList,folderList);
			}			
		}		
	}	

五、实现文件夹的复制

----------------------------------------------------

@Test
	public void tsCopyFolder()
	{
		copyFolder("D:\\test" , "F:\\ccc");
	}
	
	
	/**
	 * 拷贝文件夹
	 * @param src
	 * @param des
	 */
	public void copyFolder(String src,String des)
	{
		File file = new File(src);
		String rootFolderName = file.getName();
		des = des + "\\" + rootFolderName;	
		copyFolder_1(src,des);
	}
	
	public void copyFolder_1(String src,String des)
	{
		File file = new File(src);		
		File [] fs = file.listFiles();
		for(File f0 : fs)
		{
			if(f0.isFile()) /*如果是文件*/
			{
				copyFile(f0.getAbsolutePath(),des + "\\" + f0.getName());
			}
			else
			{
				String path = des + "\\"  +  f0.getName();
				File f = new File(path);
				f.mkdirs();
				copyFolder_1(f0.getAbsolutePath(),path);		
			}			
		}	
	}
	
	
	/**
	 * 复制文件
	 * @param src
	 * @param des
	 */
	public void copyFile(String src,String des)
	{
		try {
			
			FileInputStream fis = new FileInputStream(src);
			FileOutputStream fos = new FileOutputStream(des);
			byte [] buf = new byte[1024];
			int len = 0;
			while((len = fis.read(buf)) != -1)
			{
				fos.write(buf);
			}
			fis.close();
			fos.close();					
		} catch (Exception e) {
			e.printStackTrace();
		}
	}