IO流

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package com.java;

importjava.io.BufferedInputStream;

importjava.io.BufferedOutputStream;

importjava.io.BufferedReader;

importjava.io.BufferedWriter;

importjava.io.File;

importjava.io.FileInputStream;

importjava.io.FileNotFoundException;

importjava.io.FileOutputStream;

importjava.io.FileReader;

importjava.io.FileWriter;

importjava.io.IOException;

importorg.junit.Test;

* 重点！

* *抽象基类节点流(或文件流) 缓冲流（处理流的一种,提高数据读写的效率）

* InputStream FileInputStream BufferedInputStream(read(byte[]b))

* OutputStream FileOutputStream BufferedOutputStream(write(b,0,len)/flush())

* Reader FileReader BufferedReader(read(char[] c)/ readLine())

* Writer FileWriter BufferedWriter(write(c,0,len)/write(Stringstr) flush())

public classTestBuffered {

* 结论：

* 对于文本文件：建议使用BufferedReader / BufferedWriter

* 对于非文本文件(图片、视频、二进制文件、pdf)：BufferedInputStream / BufferedOutputStream

@Test

public void testBufferedReaderWriter() {

BufferedReader br = null;

BufferedWriter bw = null;

try {

br = new BufferedReader(newFileReader(new File("dbcp.txt")));

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

//方式一：read(char[] c)

// char[] c = new char[20];

// intlen;

// while((len = br.read(c)) != -1) {

// bw.write(c,0, len);

// bw.flush();

// }

//方式二：readLine()

Stringstr;

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

bw.write(str);

bw.newLine();

bw.flush();

}

核心代码

} catch (FileNotFoundException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

} finally {

if (bw != null) {

try {

bw.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

if (br != null) {

try {

br.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

@Test

public void testCopyFile() {

long start =System.currentTimeMillis();

String src ="C:\\Users\\shkstart\\Desktop\\1.avi";

String dest ="C:\\Users\\shkstart\\Desktop\\3.avi";

copyFile(src, dest);

long end =System.currentTimeMillis();

System.out.println("花费的时间为：" + (end - start));// 4052

}

// 使用缓冲流实现文件复制的方法

public void copyFile(String src, Stringdest) {

BufferedInputStream bis = null;

BufferedOutputStream bos = null;

try {

// 1.创建File类的对象

File file1 = new File(src);

File file2 = new File(dest);

// 2.创建相应的节点流：FileInputStream 和 FileOutputStream

FileInputStream fis = newFileInputStream(file1);

FileOutputStream fos = newFileOutputStream(file2);

// 3.创建相应的缓冲流：BufferedInputStream 和 BufferedOutputStream

bis = newBufferedInputStream(fis);

bos = newBufferedOutputStream(fos);

// 4.具体的文件复制的操作：readwrite

byte[]b = new byte[1024];

intlen;

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

bos.write(b,0, len);

bos.flush();

}

} catch (IOException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

} finally {

if (bos != null) {

try {

bos.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

if (bis != null) {

try {

bis.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

// fos.close();

// fis.close();

}

* 使用BufferedInputStream 和 BufferedOutputStream实现文件的复制

@Test

public void testBuffered1() {

BufferedInputStream bis = null;

BufferedOutputStream bos = null;

try {

// 1.创建File类的对象

File src = newFile("C:\\Users\\shkstart\\Desktop\\捕获.jpg");

File dest = newFile("C:\\Users\\shkstart\\Desktop\\捕获_1.jpg");

// 2.创建相应的节点流：FileInputStream 和 FileOutputStream

FileInputStream fis = newFileInputStream(src);

FileOutputStream fos = newFileOutputStream(dest);

// 3.创建相应的缓冲流：BufferedInputStream 和 BufferedOutputStream

bis = new BufferedInputStream(fis);

bos= new BufferedOutputStream(fos);

// 4.具体的文件复制的操作：read write

byte[] b = new byte[20];

intlen;

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

bos.write(b,0, len);

bos.flush();

}

} catch (IOException e) {

// TODO Auto-generated catchblock

e.printStackTrace();

} finally {

if (bos != null) {

try {

bos.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

if (bis != null) {

try {

bis.close();

} catch (IOException e) {

// TODOAuto-generated catch block

e.printStackTrace();

}

// fos.close();

//fis.close();

}

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