1.IO流-->用于读写文件中的数据

2.IO流的分类

import java.io.FileOutputStream;
import java.io.IOException;

public class Stream {
    public static void main(String[] args) throws IOException{
        FileOutputStream fos=new FileOutputStream("abc\\a.txt");
        fos.write(100);
        fos.close();
    }
}

3. FileInputStream

import java.io.FileOutputStream;
import java.io.IOException;

public class Stream {
    public static void main(String[] args) throws IOException{
        FileInputStream fis=new FileInputStream("abc\\a.txt");
        int b1=fis.read();
        System.out.println(b1);
        fis.close();
    }
}