writerandom.java

《A first book of java》by Gary J.Bronson 北大出版社

import java.io.*;
public class WriteRandom
{
  public static void main(String[] args)
    throws java.io.IOException
  {
    String fileName = "products.dat";
    String acctstring, amtstring, pricestring;
    int acct, amt;
    double price;
   
      // set up the keyboard for string input
    InputStreamReader isr = 
	new InputStreamReader(System.in);
    BufferedReader br = 
	new BufferedReader(isr);

      // set up the basic random access input/output stream
    RandomAccessFile raf = 
        new RandomAccessFile(fileName, "rw");

      // enter and store data for five records
    for(int i = 1; i <= 5; i++)
    {
      System.out.print("Enter the identification number: ");
      acctstring = br.readLine();
      acct = Integer.parseInt(acctstring);
      raf.writeInt(acct);    
      System.out.print("Enter the quantity in stock: ");
      amtstring = br.readLine();
      amt = Integer.parseInt(amtstring);
      raf.writeInt(amt);      
      System.out.print("Enter the price: ");
      pricestring = br.readLine();
      price = Double.parseDouble(pricestring);
      raf.writeDouble(price);
    }
    
    System.out.println("The file " + fileName + " has been written.");
    System.out.println("The length of the file is "  
                      + raf.length() + " bytes."); 
    raf.close();
  }
}