RandomAccessFile  rf=new  RandomAccessFile("f:/guodong.txt","rw");  
rf.seek(rf.length());//将指针移动到文件末尾  
System.out.println("写入文件内容为:");  
FileReader  fr=new  FileReader("f:/read.txt");  
BufferedReader  br=new  BufferedReader(fr);//读取文件的BufferedRead对象  
String  Line=br.readLine();  
while(Line!=null){  
           System.out.println(Line);  
           rf.writeBytes(Line  +  "\r\n");  
           Line=br.readLine();  
}              
                         
rf.close();  
fr.close();//关闭文件