Java中字节流和异常处理字节输入流字节输出流IO流的异常处理缓冲字节流

package com.cloud.day2;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

public class Demo1 {

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

readTest4();

}

//读取的方式一缺陷：无法读取完整一个文件的数据.

public static void readTest1() throws IOException{

//1.找到目标文件

File file = new File("F:\\a.txt");

//2.建立数据通道

FileInputStream fileInputStream = new FileInputStream(file);

//3.读取文件的数据

int content = fileInputStream.read();

System.out.println("read content:"+(char)content);

//4.关闭释放资源

fileInputStream.close();

}

//方式2 ：使用循环读取文件的数据

public static void readTest2() throws IOException{

long startTime = System.currentTimeMillis();

File file = new File("F:\\dd.jpg");

FileInputStream fileInputStream = new FileInputStream(file);

int content = 0;

while((content = fileInputStream.read())!=-1){

System.out.print((char)content);

}

fileInputStream.close();

long endTime = System.currentTimeMillis();

System.out.println("读取时间："+(endTime-startTime));

}

//方式3：使用缓冲数组读取。缺点：无法读取完整一个文件的数据。

public static void readTest3() throws IOException{

File file = new File("F:\\a.txt");

FileInputStream fileInputStream = new FileInputStream(file);

byte []buf = new byte[1024];

// 如果使用read读取数据传入字节数组，那么数据是存储到字节数组中的，

//而这时候read方法的返回值是表示的是本次读取了几个字节数据到字节数组中。

int len = fileInputStream.read(buf);

System.out.println("len="+len);

//使用字节数组构建字符串

String content = new String(buf, 0, len);

System.out.println("content:"+content);

fileInputStream.close();

}

//方式4：使用缓冲数组配合循环一起读取

public static void readTest4() throws IOException{

long startTime = System.currentTimeMillis();

File file = new File("F:\\dd.jpg");

FileInputStream fileInputStream = new FileInputStream(file);

int len = 0;

//存储读取到的数据缓冲数组的长度一般是1024的倍数，因为与计算机的处理单位。

//理论上缓冲数组越大，效率越高

byte [] buf = new byte[1024];

while((len = fileInputStream.read())!=-1){

System.out.println(new String(buf,0,len));

}

fileInputStream.close();

long endTime = System.currentTimeMillis();

System.out.println("读取时间："+(endTime-startTime));

}

package com.cloud.day2;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

public class Demo2 {

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

//1.找到目标文件

File file = new File("F:\\a.txt");

//2.建立数据输入通道

FileInputStream fileInputStream = new FileInputStream(file);

//3.缓冲字节数组读取文件

byte []buf = new byte[1024];

int length = 0;

while((length=fileInputStream.read(buf))!=-1){

System.out.println(new String(buf));

}

//4.释放资源文件

fileInputStream.close();

}

package com.cloud.day3;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo1 {

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

File inFile = new File("F:\\dd.jpg");

File destFile = new File("E:\\dd.jpg");

FileInputStream fileInputStream = new FileInputStream(inFile);

//每新创建一个FileOutputStream的时候，默认情况下FileOutputStream 的指针是指向了文件的开始的位置。

//每写出一次，指向都会出现相应移动。

FileOutputStream fileOutputStream = new FileOutputStream(destFile);

//建立缓冲数据，边读边写

byte []buf = new byte[1024];

int length=0;

while((length=fileInputStream.read())!=-1){

fileOutputStream.write(buf, 0, length);

}

//关闭原则，先开后关，后开先关

fileOutputStream.close();

fileInputStream.close();

}

package com.cloud.day3;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo2 {

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

writeTest1();

}

//使用字节数组写出数据

//每次只能写一个字节的数据出去

public static void writeTest1() throws IOException{

File file = new File("F:\\a.txt");

FileOutputStream fileOutputStream = new FileOutputStream(file);

fileOutputStream.write('s');

fileOutputStream.write('p');

fileOutputStream.write('r');

fileOutputStream.write('i');

fileOutputStream.write('n');

fileOutputStream.write('g');

fileOutputStream.close();

}

package com.cloud.day3;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Arrays;

public class Demo3 {

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

readTest();

}

public static void readTest() throws IOException{

File file = new File("F:\\a.txt");

FileInputStream fileInputStream = new FileInputStream(file);

byte []buf=new byte[1024];

int length = fileInputStream.read(buf);

System.out.println("字节数组的内容是："+Arrays.toString(buf));

fileInputStream.close();

}

public static void writeTest()throws FileNotFoundException,IOException{

File file = new File("F:\\a.txt");

FileOutputStream fileOutputStream = new FileOutputStream(file);

fileOutputStream.write(511);

fileOutputStream.close();

}

package com.cloud.day3;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo4 {

public static void main(String[] args) {

copyImage();

}

//拷贝图片

public static void copyImage(){

FileInputStream fileInputStream = null;

FileOutputStream fileOutputStream = null;

try {

//找到目标文件

File inFile = new File("F:\\dd.jpg");

File outFile = new File("F:\\d.jpg");

//建立流通道

fileInputStream = new FileInputStream(inFile);

fileOutputStream = new FileOutputStream(outFile);

//建立缓冲数组，边读边写

byte[] buf = new byte[1024];

int length = 0;

while((length = fileInputStream.read(buf))!=-1){

fileOutputStream.write(buf, 0, length);

}

} catch (IOException e) {

System.out.println("拷贝图片出错...");

throw new RuntimeException(e);

}finally{

try {

if(fileOutputStream!=null){

fileOutputStream.close();

System.out.println("关闭输出流对象成功...");

}

} catch (IOException e) {

System.out.println("关闭输出流对象失败...");

throw new RuntimeException(e);

}finally{

if(fileInputStream!=null){

try {

fileInputStream.close();

System.out.println("关闭输入流成功...");

} catch (IOException e) {

System.out.println("关闭输入流失败...");

throw new RuntimeException(e);

}

//读取文件测试

public static void readTest(){

FileInputStream fileInputStream = null;

try {

//找到目标文件

File file = new File("F:\\a.txt");

//建立数据输入通道

fileInputStream = new FileInputStream(file);

//建立缓冲数组读取数据

byte[] buf = new byte[1024];

int length = 0;

while((length = fileInputStream.read(buf))!=-1){

System.out.println(new String(buf, 0, length));

}

} catch (IOException e) {

System.out.println("读取资源文件出错...");

throw new RuntimeException(e);

}finally{

try {

if(fileInputStream!=null){

fileInputStream.close();

System.out.println("关闭资源文件成功...");

}

} catch (IOException e) {

System.out.println("关闭资源文件失败...");

throw new RuntimeException(e);

}

package com.cloud.day3;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo5 {

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

readTest();

}

public static void readTest2() throws IOException{

File file = new File("F:\\a.txt");

FileInputStream fileInputStream = new FileInputStream(file);

BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

bufferedInputStream.read();

FileOutputStream fileOutputStream = new FileOutputStream(file);

BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

fileOutputStream.write(null);

//读取文件数据

int content = 0;

while((content = fileInputStream.read())!=-1){

System.out.println((char)content);

}

//关闭资源,这里实际上是关闭FileInputSream

bufferedInputStream.close();

}

public static void readTest() throws IOException{

//读取文件使用缓冲数组

File file = new File("F:\\a.txt");

FileInputStream fileInputStream = new FileInputStream(file);

//建立缓冲数组读取数据

byte[] buf = new byte[1024];

int length = 0;

while((length = fileInputStream.read(buf))!=-1){

System.out.println(new String(buf, 0, length));

}

fileInputStream.close();

}

package com.cloud.day3;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo6 {

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

File file = new File("F:\\a.txt");

FileOutputStream fileOutputStream = new FileOutputStream(file);

BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

bufferedOutputStream.write("Hello,world".getBytes());

bufferedOutputStream.close();

}

package com.cloud.day3;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

public class Demo7 {

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

//找到目标文件

File inFile = new File("F:\\dd.jpg");

File outFile = new File("F:\\1.jpg");

//建立数据通道

FileInputStream fileInputStream = new FileInputStream(inFile);

FileOutputStream fileOutputStream = new FileOutputStream(outFile);

//建立缓冲流

BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

//边读边写

int content = 0;

while((content = bufferedInputStream.read())!=-1){

bufferedOutputStream.write(content);

}

bufferedInputStream.close();

bufferedOutputStream.close();

}

Java中字节流和异常处理字节输入流字节输出流IO流的异常处理缓冲字节流

字节输入流

字节输入流流程

流关闭问题

拷贝图片

字节输出流

字节输出流流程

写数据的类型

IO流的异常处理

缓冲字节流

缓冲字节输入流

缓冲字节输出流

缓冲字节流拷贝图片

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