package java;

import org.junit.Test;

import java.io.*;

/*** 处理流之一：缓冲流的使用** 1.缓冲流：* BufferedInputStream* BufferedOutputStream* BufferedReader* BufferedWriter** 2.作用：提供流的读取、写入的速度* 提高读写速度的原因：内部提供了一个缓冲区** 3. 处理流，就是“套接”在已有的流的基础上。**/

public class BufferedTest {

/*实现非文本文件的复制*/

@Test

public void BufferedStreamTest() throws FileNotFoundException {

BufferedInputStream bis = null;

BufferedOutputStream bos = null;

try {

//1.造文件 File srcFile = new File("爱情与友情.jpg");

File destFile = new File("爱情与友情3.jpg");

//2.造流 //2.1 造节点流 FileInputStream fis = new FileInputStream((srcFile));

FileOutputStream fos = new FileOutputStream(destFile);

//2.2 造缓冲流 bis = new BufferedInputStream(fis);

bos = new BufferedOutputStream(fos);

//3.复制的细节：读取、写入 byte[] buffer = new byte[10];

int len;

while((len = bis.read(buffer)) != -1){

bos.write(buffer,0,len);

// bos.flush();//刷新缓冲区

}

} catch (IOException e) {

e.printStackTrace();

} finally {

//4.资源关闭 //要求：先关闭外层的流，再关闭内层的流 if(bos != null){

try {

bos.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if(bis != null){

try {

bis.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//说明：关闭外层流的同时，内层流也会自动的进行关闭。关于内层流的关闭，我们可以省略.// fos.close();// fis.close(); }

}

//实现文件复制的方法 public void copyFileWithBuffered(String srcPath,String destPath){

BufferedInputStream bis = null;

BufferedOutputStream bos = null;

try {

//1.造文件 File srcFile = new File(srcPath);

File destFile = new File(destPath);

//2.造流 //2.1 造节点流 FileInputStream fis = new FileInputStream((srcFile));

FileOutputStream fos = new FileOutputStream(destFile);

//2.2 造缓冲流 bis = new BufferedInputStream(fis);

bos = new BufferedOutputStream(fos);

//3.复制的细节：读取、写入 byte[] buffer = new byte[1024];

int len;

while((len = bis.read(buffer)) != -1){

bos.write(buffer,0,len);

}

} catch (IOException e) {

e.printStackTrace();

} finally {

//4.资源关闭 //要求：先关闭外层的流，再关闭内层的流 if(bos != null){

try {

bos.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if(bis != null){

try {

bis.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//说明：关闭外层流的同时，内层流也会自动的进行关闭。关于内层流的关闭，我们可以省略.// fos.close();// fis.close(); }

}

@Test

public void testCopyFileWithBuffered(){

long start = System.currentTimeMillis();

String srcPath = "C:\\Users\\Administrator\\Desktop\\01-视频.avi";

String destPath = "C:\\Users\\Administrator\\Desktop\\03-视频.avi";

copyFileWithBuffered(srcPath,destPath);

long end = System.currentTimeMillis();

System.out.println("复制操作花费的时间为：" + (end - start));//618 - 176 }

/*使用BufferedReader和BufferedWriter实现文本文件的复制*/

@Test

public void testBufferedReaderBufferedWriter(){

BufferedReader br = null;

BufferedWriter bw = null;

try {

//创建文件和相应的流 br = new BufferedReader(new FileReader(new File("dbcp.txt")));

bw = new BufferedWriter(new FileWriter(new File("dbcp1.txt")));

//读写操作 //方式一：使用char[]数组// char[] cbuf = new char[1024];// int len;// while((len = br.read(cbuf)) != -1){// bw.write(cbuf,0,len);// // bw.flush();// }

//方式二：使用String String data;

while((data = br.readLine()) != null){

//方法一：// bw.write(data + "\n");//data中不包含换行符 //方法二： bw.write(data);//data中不包含换行符 bw.newLine();//提供换行的操作

}

} catch (IOException e) {

e.printStackTrace();

} finally {

//关闭资源 if(bw != null){

try {

bw.close();

} catch (IOException e) {

e.printStackTrace();

}

}

if(br != null){

try {

br.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

}