InputStream 、 InputStreamReader和BufferedReader（out同理）

1. InputStream ：是所有字节输入流的超类，一般使用它的子类：FileInputStream等，它能输出字节流；
2. InputStreamReader ：是字节流与字符流之间的桥梁，能将字节流输出为字符流，并且能为字节流指定字符集，可输出一个个的字符；
3. BufferedReader ：提供通用的缓冲方式文本读取，readLine读取一个文本行， 从字符输入流中读取文本，缓冲各个字符，从而提供字符、数组和行的高效读取。

  1、InputStream

package src;


import java.io.*;

public class FileIO {
    public static void main(String[] args) throws IOException {
        int i=0;
        File file=new File("D:/liuyifei.jpeg");
        FileInputStream fileInputStream=new FileInputStream(file);
        int available = fileInputStream.available();
        FileOutputStream fileOutputStream=new FileOutputStream(new File("D:/liuyifei.txt"));
        byte[] bytes=new byte[available];
        while(fileInputStream.read()!=-1){
            fileInputStream.read(bytes);
        }
        System.out.println(bytes);
        fileOutputStream.write(bytes);
        FileInputStream fileInputStream1=new FileInputStream(file);
        byte[] bytes1=new byte[available];
        fileInputStream1.read(bytes1);
        FileOutputStream fileOutputStream1=new FileOutputStream(new File("D:/beautifuls.jpeg"));
        fileOutputStream1.write(bytes1);
    }
    }

2、BufferedReader

import sun.misc.base64Decoder;

import java.io.*;

public class base64 {
    public static void main(String[] args) throws IOException {
        String fileName = "img_base64.txt";
        File file = new File(fileName);
        BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
        StringBuffer stringBuffer = new StringBuffer();
        String buffer;
        while ((buffer = bufferedReader.readLine()) != null) {
            stringBuffer.append(buffer);
        }
        base64Decoder base64decoder = new base64Decoder();
        byte[] bytes = base64decoder.decodeBuffer(stringBuffer.toString());
        FileOutputStream outputStream = new FileOutputStream(new File("genrerate.png"));
        outputStream.write(bytes);
    }
}

3、InputStreamReader

package src;


import java.io.*;

public class FileIO {
    public static void main(String[] args) throws IOException {
        int i=0;
        File file=new File("D:/liuyifei.jpeg");
        FileInputStream fileInputStream=new FileInputStream(file);
        int available = fileInputStream.available();

        InputStreamReader inputStreamReader=new InputStreamReader(fileInputStream);
        while (inputStreamReader.read()!=-1){
            System.out.println(inputStreamReader.read());
        }
    }
    }