1、9*9乘法口诀打印到test2.txt中，代码如下

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

public class week {

         publicstatic void main(String[] args) throws Exception {

          File txt = newFile("d:"+File.separator+"test2.txt");

          FileOutputStream h = newFileOutputStream("d:"+File.separator+"test2.txt");

          if(!txt.exists())

          {

                    txt.createNewFile();

          }

          String s = new String();

          try

          {

        for(int i=1;i<=9;i++)

          {

                   for(int j=1;j<=i;j++)

                   {

                         System.out.print(i+"*"+j+"="+(i*j)+"");

                         if(i==j)

                         {

                                  s =(i+"*"+j+"="+(i*j)+"\r\n");       

                         }

                         else

                         {

                                  s =(i+"*"+j+"="+(i*j)+" ");

                         }

                    h.write(s.getBytes());                                

                    }

                    System.out.println();

           } 

          }

          catch(Exception e)

              {

     e.printStackTrace();

              }

          finally

          {

                    h.close();

          }

         }

}

2、将test2.txt内的乘法口诀打印到屏幕上

import java.io.File;

import java.io.FileInputStream;

publicclassweek1 {

    publicstaticvoid main(String[] args) throws Exception {

     File txt = new File("d:"+File.separator+"test2.txt");

     FileInputStream h = new FileInputStream("d:"+File.separator+"test2.txt");

     try

     {

         byte[] buff = newbyte[(int)txt.length()];

         h.read(buff);

         String tmp = new String(buff);

         System.out.println(tmp);

     }

     catch(Exception e)

         {

     e.printStackTrace();

         }

     finally

     {

        h.close();

     }

    }

}

代码写的不是很规范，仅供参考。