演示MP3的复制，通过缓冲区。

import java.io.*;
class CopyMp3 
{
    public static void main(String[] args) throws IOException
    {
        long start = System.currentTimeMillis();
        copy_2();
        long end = System.currentTimeMillis();

        System.out.println((end-start)+"毫秒");
    }
    public static void copy_2()throws IOException
    {
        MyBufferedInputStream bufis = new MyBufferedInputStream(new FileInputStream("E:\\Ziliao\\Java\\practice\\0.mp3"));
        BufferedOutputStream bufos = new BufferedOutputStream(new FileOutputStream("E:\\Ziliao\\Java\\practice\\2.mp3"));

        int by = 0;

        while ((by=bufis.myRead())!=-1)
        {
            bufos.write(by);
        }
        bufos.close();
        bufis.myClose();
    }
    //通过字节流的缓冲区完成复制。
    public static void copy_1()throws IOException
    {
        BufferedInputStream bufis = new BufferedInputStream(new FileInputStream("E:\\Ziliao\\Java\\practice\\1.mp3"));
        BufferedOutputStream bufos = new BufferedOutputStream(new FileOutputStream("E:\\Ziliao\\Java\\practice\\2.mp3"));

        int by = 0;

        while ((by=bufis.read())!=-1)
        {
            bufos.write(by);
        }

        bufos.close();
        bufis.close();
    }
}

复制一张图片。
思路：
1，用字节读取流对象和图片关联。
2，用字节写入流对象创建一个图片文件，用于存储获取到的图片数据。
3，通过循环读写，完成数据存储。
4，关闭资源。

import java.io.*;
class CopyPic 
{
    public static void main(String[] args) 
    {
        FileOutputStream fos = null;
        FileInputStream fis = null;
        try
        {
            fos = new FileOutputStream("E:\\Ziliao\\Java\\practice\\2.jpg");
            fis = new FileInputStream("E:\\Ziliao\\Java\\practice\\1.jpg");

            byte[] buf = new byte[1024];

            int len = 0;

            while ((len=fis.read(buf))!=-1)
            {
                fos.write(buf,0,len);
            }
        }
        catch (IOException e)
        {
            throw new RuntimeException("复制文件失败");
        }
        finally
        {
            try
            {
                if(fis!=null)
                    fis.close();
            }
            catch (IOException e)
            {
                throw new RuntimeException("写入关闭失败");
            }
        }
    }
}

通过缓冲区复制一个.java文件。

import java.io.*;
class CopyTextByBuf 
{
    public static void main(String[] args) throws IOException
    {
        BufferedReader bufr = null;
        BufferedWriter bufw = null;

        try
        {
            bufr = new BufferedReader(new FileReader("BufferedWriterDemo.java"));
            bufw = new BufferedWriter(new FileWriter("bufwiter_Copy.txt"));

            String line = null;

            while ((line=bufr.readLine())!=null)
            {
                bufw.write(line);
                bufw.newLine();
                bufw.flush();
            }
        }
        catch (IOException e)
        {
            throw new RuntimeException("读写失败");
        }
        finally
        {
            try
            {
                if(bufr!=null)
                    bufr.close();
            }
            catch (IOException e)
            {
                throw new RuntimeException("读取关闭失败");
            }
            try
            {
                if(bufw!=null)
                    bufw.close();
            }
            catch (IOException e)
            {
                throw new RuntimeException("写入关闭失败");
            }
        }
    }
}