java 输入输出流 关于InputStream 和 OutputSteam 实现文本一行一行读入和 文本一行一行输出

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.OutputStream;
import java.io.InputStream;
import java.util.Random;

//import java.io.StringBufferInputStream;

public class Number1 {
    public static void main( String arg[] )throws Exception {
        Random rad = new Random();
        File file = new File("D:"+File.separator+"tt.txt");
        file.createNewFile();
        OutputStream out = new FileOutputStream(file); 
        for( int i = 100; i >= 0; i-- )
        {
            int n = rad.nextInt(4)+1; StringBuffer str = new StringBuffer();
            for( int j = 0; j < n; j++ )str.append((char)(rad.nextInt(26) + ‘a‘));
            str.append("\r\n"); 
            out.write(str.toString().getBytes());
        }
        File file2 = new File("D:"+File.separator+"xx.txt");
        file2.createNewFile();
        OutputStream output = new FileOutputStream(file2);
        
        InputStream in = new FileInputStream(file);
        byte b[] = new byte[100]; int sum = 0;
        int len = (int)file.length();
        for( int i = 0; i < len; i++ ){
            byte temp = (byte)in.read();
            if( temp != (byte)‘\r‘ && temp != (byte)‘\n‘ )
                b[sum++] = temp;
            else{
                  output.write( new String(b,0,sum).getBytes() ); sum = 0; 
                  if( temp == (byte)‘\r‘) output.write( (byte)‘\r‘ );
                  else output.write( (byte)‘\n‘);
                }
        }
        in.close();
        out.close();
    }
}