JavaIO使用字节流读写数据

【声明】本文参考自极客学院视频 1、字节流读文件

import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; public class ReadByteStream { public static void main(String[] args) { // TODO Auto-generated method stub try { FileInputStream fis=new FileInputStream("text.txt"); byte input[]=new byte[21]; fis.read(input); //String inputString=new String(input); String inputString=new String(input, "GBk"); System.out.println(inputString); //关闭 fis.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }

2、字节流写文件

import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; public class WriteByteStream { public static void main(String[] args) { // TODO Auto-generated method stub try { FileOutputStream fos=new FileOutputStream("textw.txt"); String outString="write 123456写出数据"; byte output[]=outString.getBytes("GBK"); fos.write(output); //关闭 fos.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }

3、通过字节输入输出实现文件拷贝

import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; //通过字节输入输出实现文件拷贝 public class CopyByByteStream { public static void main(String[] args) { // TODO Auto-generated method stub try { FileInputStream fis=new FileInputStream("ani.gif"); FileOutputStream fos=new FileOutputStream("ani_new.gif"); byte input[]=new byte[50]; while (fis.read(input)!=-1) { fos.write(input); } fis.close(); fos.close(); System.out.println("done"); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }