使用ObjectOutputStream类将对象顺序写入文件。

import java.io.IOException;

import java.io.ObjectOutputStream;/**来自 时代Java公众号 - nowjava.com**/

import java.nio.file.Files;

import java.nio.file.Paths;

import java.util.NoSuchElementException;

import java.util.Scanner;


public class Main

{

   private static ObjectOutputStream output; // outputs data to file


   public static void main(String[] args)

   {

      openFile();

      addRecords();

      closeFile();

   }


   // open file clients.ser
   /*
   时代Java公众号 - nowjava.com
   */

   public static void openFile()

   {

      try 

      {

         output = new ObjectOutputStream(

            Files.newOutputStream(Paths.get("clients.ser")));

      }

      catch (IOException ioException)

      {

         System.err.println("Error opening file. Terminating.");

         System.exit(1); // terminate the program

      } 

   } 


   // add records to file

   public static void addRecords()

   {

      Scanner input = new Scanner(System.in);


      System.out.printf("%s%n%s%n? ", 

         "Enter account number, first name, last name and balance.",

         "Enter end-of-file indicator to end input.");


      while (input.hasNext()) // loop until end-of-file indicator

      {

         try 

         {

            // create new record; this example assumes valid input

            Account record = new Account(input.nextInt(),

               input.next(), input.next(), input.nextDouble());


            // serialize record object into file

            output.writeObject(record); 

         } 

         catch (NoSuchElementException elementException)

         {

            System.err.println("Invalid input. Please try again.");

            input.nextLine(); // discard input so user can try again 

         } 

         catch (IOException ioException)

         {

            System.err.println("Error writing to file. Terminating.");

            break;

         } 


         System.out.print("? ");

      }

   } 


   // close file and terminate application 

   public static void closeFile() 

   {

      try 

      {

         if (output != null)

            output.close();

      } 

      catch (IOException ioException)

      {

         System.err.println("Error closing file. Terminating.");

      } 

   } 

}



class Account implements java.io.Serializable

{

   private int account;

   private String firstName;

   private String lastName;

   private double balance;

   

   // initializes an Account with default values

   public Account() 

   {

      this(0, "", "", 0.0); // call other constructor

   } 

  

   // initializes an Account with provided values

   public Account(int account, String firstName, 

      String lastName, double balance)

   {

      this.account = account;

      this.firstName = firstName;

      this.lastName = lastName;

      this.balance = balance;

   }


   // set account number   

   public void setAccount(int acct)

   {

      this.account = account;

   } 


   // get account number   

   public int getAccount() 

   { 

      return account; 

   } 

   

   // set first name   

   public void setFirstName(String firstName)

   {

      this.firstName = firstName;

   }