缓冲字节流

public class BufferTest {
    public static void main(String[] args) throws Exception {
//        testBufferedInputStream();
//            testBufferedOutputStream();
        copyFile();
    }
    /*
        缓冲字节输入流
     */
    public static void testBufferedInputStream() throws Exception{
        //文件字节输入流对象
        FileInputStream in = new FileInputStream("C:\\Users\\Administrator\\Desktop\\JavaSE\\基本语法\\src\\com\\缓冲流\\tt");
        //把文件字节输入流放到缓冲字节输入流对象
        BufferedInputStream br = new BufferedInputStream(in);
        byte[] b = new byte[1024];
        int len = 0;
        while ((len = br.read(b)) != -1){
            System.out.println(new String(b,0,len));
        }
        //最晚开的流最早关，然后依次关
        br.close();
        in.close();
    }
    /*
        缓冲字节输出流
     */
    public static void testBufferedOutputStream() throws Exception{
        FileOutputStream fileOutputStream = new FileOutputStream("C:\\Users\\Administrator\\Desktop\\JavaSE\\基本语法\\src\\com\\缓冲流\\tt1");
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
        String s = "helloworld";
        bufferedOutputStream.write(s.getBytes());//写到内存中
        bufferedOutputStream.flush();//刷写到硬盘上
        bufferedOutputStream.close();
        fileOutputStream.close();
    }
    /*
        用缓冲流实现文件的复制
     */
    public static void copyFile() throws Exception{
        BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream("C:\\Users\\Administrator\\Desktop\\JavaSE\\基本语法\\src\\com\\缓冲流\\tt1"));
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("C:\\Users\\Administrator\\Desktop\\JavaSE\\基本语法\\src\\com\\缓冲流\\tt"));
        byte[] b = new byte[1024];
        int len = 0;
        //设置一个读取的数据长度，直到bufferedOutputStream.read方法执行到最后(比方说，文件中只有helloworld，执行到最后一个就是读取d的后面，这时候返回值为-1)
        while ((len = bufferedInputStream.read(b)) != -1){
            bufferedOutputStream.write(b,0,len);
        }
        bufferedOutputStream.flush();
        bufferedOutputStream.close();
        bufferedInputStream.close();
    }
}