自定义字节流缓冲区复制歌曲出了点小状况 - 黑马程序员技术交流社区

/*
自定义一个字节流缓冲区
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
class MyBufferedInputStream
{
private InputStream is;
int pos=0,count=0;
byte[] bufb = new byte[1024];
MyBufferedInputStream(InputStream is)
{
this.is = is;
}
public int myRead() throws IOException
{
//当count==0时，需从硬盘中取数据到缓冲区(即bufb中)。
if(count==0)
{
count = is.read(bufb);
System.out.println("if1 count = "+count);
if(count<0)//当count<0，说明硬盘中已无数据，不必读取，故返回-1
return -1;
pos = 0;//每重新装载一次缓冲区，需将pos置0
}
//当count>0时，需读取缓冲区的数据
if(count>0)
{
byte b = bufb[pos++];
count--;
System.out.println("if2 count = "+count);
return b&255;// 先将b由byte转为int,然后保留低8位，高位置0
}
return -1;//?????????????
}
public void close() throws IOException
{
is.close();
}
}
class MyBufferedInputStreamDemo
{
public static void main(String[] args) throws IOException
{
long start = System.currentTimeMillis();
copy();
long end = System.currentTimeMillis();
System.out.println("time = "+(end-start));
}
//复制歌曲
public static void copy() throws IOException
{
MyBufferedInputStream mbis = null;
FileOutputStream fos = null;
try
{
mbis = new MyBufferedInputStream(new FileInputStream("d:\\G.E.M. 邓紫棋 - 后会无期.mp3"));
fos = new FileOutputStream("f:\\邓紫棋.mp3");
int b;
while((b=mbis.myRead())!=-1)
{
fos.write(b);
}
}
catch (IOException e)
{
throw new IOException("读写异常");
}
finally
{
if(mbis!=null)
try
{
mbis.close();
}
catch (IOException e)
{
throw new IOException("读资源关闭异常");
}
if(fos!=null)
try
{
fos.close();
}
catch (IOException e)
{
throw new IOException("写资源关闭异常");
}
}
}
}

复制代码

package test;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
/*
自定义一个字节流缓冲区
*/
import java.io.IOException;
import java.io.InputStream;
class MyBufferedInputStream {
private InputStream is;
int pos = 0;
int count = 0;
byte[] bufb = new byte[1024];
MyBufferedInputStream(InputStream is) {
this.is = is;
}
public int read() throws IOException {
// 当count==0时，需从硬盘中取数据到缓冲区(即bufb中)。
if (count == 0) {
count = is.read(bufb);
// System.out.println("if1 count = " + count);
if (count < 0) { // 当count<0，说明硬盘中已无数据，不必读取，故返回-1
return -1;
}
pos = 0; // 每重新装载一次缓冲区，需将pos置0
count--;// 重新一次读到数据、自然返回第一个啊
return bufb[pos] & 255;
}
else{
// 当count>0时，需读取缓冲区的数据
if (count > 0) {
// 先把pos 自加一次，在取值。不然还是0.毕老师是在上面pos++
byte b = bufb[++pos];// 改为byte b = bufb[++pos]
count--;
// System.out.println("if2 count = " + count);
return b & 255; // 先将b由byte转为int,然后保留低8位，高位置0
}
}
return -1; // ?????????????这里是逻辑上不会被执行到的，为了语法正确
}
public void close() throws IOException {
is.close();
}
}
public class MyBufferedInputStreamDemo {
public static void main(String[] args) throws IOException {
long start = System.currentTimeMillis();
copy();
long end = System.currentTimeMillis();
System.out.println("time = " + (end - start));
}
// 复制歌曲
public static void copy() throws IOException {
MyBufferedInputStream mbis = null;
FileOutputStream fos = null;
// BufferedOutputStream fos=null;
try {
// mbis = new MyBufferedInputStream(new FileInputStream(
// "d:\\G.E.M. 邓紫棋 - 后会无期.mp3"));
// fos = new FileOutputStream("f:\\邓紫棋.mp3");
mbis = new MyBufferedInputStream(new FileInputStream("f:\\1.mp3"));
fos = new FileOutputStream("f:\\2.mp3");
// fos=new BufferedOutputStream(new FileOutputStream("f:\\2.mp3") );
//复制完MP3 之后一定要查看一下文件大小。看字节，最好在复制一次图片
//测试时发现，mp3 错误了一点也可以播放，你可以把bufb[++pos];改为 bufb[pos++]
//文件大小一样，MP3可以播放，但声音失真了。复制图片直接打不开
// mbis = new MyBufferedInputStream(new FileInputStream("f:\\fis.jpg"));
// fos = new FileOutputStream("f:\\fos.jpg");
// fos=new BufferedOutputStream(new FileOutputStream("f:\\2.mp3") );
int b;
while ((b = mbis.read())!=-1) {
fos.write(b);
}
} catch (IOException e) {
throw new IOException("读写异常");
} finally {
if (mbis != null) {
try {
mbis.close();
} catch (IOException e) {
throw new IOException("读资源关闭异常");
}
}
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
throw new IOException("写资源关闭异常");
}
}
}
}
}

复制代码