为什么会出现错误，将夜COPY2复制错误。

package project3_8_4filedemo_copy;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

public class CopyDemo {

public static void main(String[] args) throws FileNotFoundException {

// 不使用缓冲流的方式复制文件

FileInputStream fis = null;

FileOutputStream fos = null;

FileOutputStream fos1 = null;

try {

fis = new FileInputStream("将夜.txt");

fos = new FileOutputStream("将夜copy.txt");

long start01 = System.currentTimeMillis();

int n = 0;

while ((n = fis.read()) != -1) {

fos.write(n);

}

fos.close();

long end01 = System.currentTimeMillis();

System.out.println("非缓冲流方式复制文件用时：" + (end01 - start01));

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

// 使用缓冲流的方式复制文件

BufferedInputStream bis = new BufferedInputStream(new FileInputStream("将夜.txt"));

BufferedOutputStream bos = new BufferedOutputStream(fos1);

long start02 = System.currentTimeMillis();

try {

fos1 = new FileOutputStream("将夜copy2.txt");

int i = 0;

byte[] b = new byte[1024];

while ((i = bis.read(b)) != -1) {

bos.write(b, 0, i);

bos.flush();

}

fos1.close();

fis.close();

bos.close();

bis.close();

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

long end02 = System.currentTimeMillis();

System.out.println("非缓冲流方式复制文件用时：" + (end02 - start02));

}

}