NIO学习总结

/** 
  * 使用传统的I/O读取文件内容
  * @param filePath  文件路径
   * @throws IOException
*/
 public static void ioRead(String filePath) throws IOException {
        File file = new File(filePath);
        FileInputStream fis = new FileInputStream(file);
        byte[] b = new byte[1024];
        fis.read(b);
        System.out.println(new String(b));
 }

/**
  * 使用NIO读取文件内容
  * @param filePath 文件路径
  * @throws IOException
*/
  public static void nioRead(String filePath) throws IOException {
        File file = new File(filePath);
        FileInputStream fis = new FileInputStream(file);
        FileChannel channel = fis.getChannel();
        ByteBuffer b = ByteBuffer.allocate(1024);
        channel.read(b);
        byte[] by = b.array();
        System.out.println(new String(by));
  }
	
/**
  * 传统I/O写文件
  * 
  * @param filePath  文件路径
  * @throws IOException
*/
  public static void ioWrite(String filePath) throws IOException 
  {
        File file = new File(filePath);
        FileOutputStream fos = new FileOutputStream(file);
        String[] contents = new String[] { "qian", "hao" };
        for (String content : contents) 
        {
	   byte[] b = content.getBytes(Charset.forName("UTF-8"));
	   fos.write(b);
        }
   }

/**
  * NIO写文件
  * @param filePath 文件路径
  * @throws IOException
*/
 public static void nioWrite(String filePath) throws IOException
 {
        File file = new File(filePath);
        FileOutputStream fos = new FileOutputStream(file);
        // 获取文件通道
         FileChannel channel = fos.getChannel();
        // 设置文件缓冲区
         ByteBuffer buffer = ByteBuffer.allocate(1024);
        String[] contents = new String[] { "qian", "hao" };
        // 将数据读入缓冲区中
         for (String content : contents) 
       {
	  buffer.put(content.getBytes());
       }
       // 通道反转(将读通道转化为写通道)
	  buffer.flip();
       // 将文件写入写通道中
	  channel.write(buffer);
 }

/**
  * 将一个文件内容复制到另外一个文件中
  * @param resource  源文件路径
  * @param destination 目标文件路径
  * @throws IOException
*/
 public static void nioCopyFile(String resource, String destination)
				throws IOException 
{
       // 设置文件输入流
        FileInputStream fis = new FileInputStream(resource);
       // 设置文件输出流
        FileOutputStream fos = new FileOutputStream(destination);
       // 设置输入通道
        FileChannel readChannel = fis.getChannel();
       // 设置输出通道
        FileChannel writeChannel = fos.getChannel();
       // 创建缓冲区
        ByteBuffer buffer = ByteBuffer.allocate(1024);
       // 复制文件
        while (true) 
       {
        // 清空缓冲，使其接受新的数据
	buffer.clear();
        // 从输入通道中将数据写入缓冲区中
	int len = readChannel.read(buffer);
        // 判断是否文件已读取完成
	if (len == -1) 
         {
	   break;
	}
        // 将缓冲区的数据些到另外一个通道，(输入通道反转到输出通道)
	   buffer.flip();
        // 从输出通道将数据写到缓冲区,写入文件中
	   writeChannel.write(buffer);
	}
 }