demoraf.java

《J2EE专业项目实例开发》源代码

import java.io.*;
class demoRAF
{
              demoRAF()
              {
                            try
                            {
                            char read;
                            System.out.println("Do you want to enter text in a file? (y/n)--->");
                            BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
                            read=(char)reader.read(); //read the selection made by the user
                            if((read == 'y')||(read == 'Y'))
                            openFile();
                            else
                            System.out.println("Quitting..........");
                            }
                            catch(Exception e)
                            {
                            System.out.println("Exception occurred: " + e);
                            }
              }
              public static void main(String[] args)
              {
                            demoRAF demo=new demoRAF();	
              }
              void openFile()
              {
                            try
                            {
                            String fileName;
                            String readline;
                            BufferedReader reader=new BufferedReader(new InputStreamReader(System.in)); 
                            System.out.println("Enter file name where you want to enter text--->");
                            fileName=reader.readLine(); //read the filename
                            long ptr=0;
                            RandomAccessFile file=new RandomAccessFile(fileName,"rw"); //access the file
                            System.out.println("Enter text--->");
                            readline=reader.readLine(); //read the text entered
                            ptr=file.length(); //get the length of the file
                            file.seek(ptr); //place the file pointer at the end of the file
                            file.writeBytes(readline); //write to the file
                            }
                            catch(Exception e)
                            {
                            System.out.println("Exception occurred: " + e);
                            }
              }
}