IO流学习笔记

什么是流
流是一组有序的，有起点和终点的字节集合，是对计算机中数据传输的总称或者抽象
即数据在两个设备间的传输称为流，流的本质是数据传输。

流序列中的数据可以是没有进行加工的原始数据（二进制字节数据），也可以是经过编码的符合某种格式规定的数据，Java中提供了不同的流类对它们进行处理。

流按照传输方向可以分为

输入流    含有Input

输出流    含有Output

按照传输方式可以分为

字节流    含有stream

字符流    不含stream

import java.io.*;public class ExampleIo {    public static void main(String[] args)throws Exception {        new ExampleIo().bufferReaderWriter();    }    //字节流读取文件    public void zifuliuReader() throws Exception{        File ff=new File("E:\\today.txt");        FileInputStream in =new FileInputStream(ff);        int xx=0;        String   value="";        while ((xx=in.read())!=-1){            System.out.print((char) xx);            value+=(char)xx;        }        in.close();    }    //字符流读取文件    public void zijieReader()throws Exception{        File ff=new File("E:\\today.txt");        int xx=0;        FileReader rd=new FileReader(ff);        while ((xx=rd.read())!=-1){            System.out.print((char)xx);        }        rd.close();    }    //字节流写入文件    public  void zijieWriter()throws Exception{        File ff=new File("E:\\today.txt");        OutputStream out=new FileOutputStream(ff);        String zz="today is a good day";        byte[] b=zz.getBytes();        InputStream  io2=new ByteArrayInputStream(b);        byte[] bs=new byte[1024];        int len=0;        while ((len=io2.read(bs))!=-1){            out.write(bs,0,len);        }        io2.close();        out.close();    }    //字符流写入文件    public void zifuWriter()throws Exception{        File ff=new File("E:\\today.txt");        FileWriter writer=new FileWriter(ff);        writer.write("今天是个好日子");        writer.close();    }    //字符流转换字节流的桥梁  可使用指定的 charset 将要写入流中的字符编码成字节。    public void TranferToZiJie()throws Exception{        File ff=new File("E:\\today.txt");        FileOutputStream out=new FileOutputStream(ff);        OutputStreamWriter writer=new OutputStreamWriter(out,"utf-8");        writer.write("今天是个好日子");        writer.close();    }    //将字节流向字符流的转换    public void TranferToZiFu()throws Exception{        File ff=new File("E:\\today.txt");        InputStreamReader in=new InputStreamReader(new FileInputStream(ff),"utf-8");        char[] b=new char[1024];        int s=in.read(b);        System.out.println(new String(b,0,s));        in.close();    }    //利用缓冲区读写文件    public  void bufferReaderWriter()throws  Exception{        File ff=new File("E:\\today.txt");        InputStreamReader in=new InputStreamReader(new FileInputStream(ff),"utf-8");        BufferedReader rd=new BufferedReader(in);        String value="";        while ((value=rd.readLine())!=null){            System.out.println(value);        }        rd.close();        OutputStreamWriter writer=new OutputStreamWriter(new FileOutputStream(ff),"utf-8");        BufferedWriter bf=new BufferedWriter(writer);        bf.write("今天是个好日子");        bf.close();    }}