为什么我会遇到classcastexception以及我使用的类型有什么问题？

Question

我已经用Google搜索了这个主题好几天了，找不到我的问题的答案。在我的＆＃34; tryReadClub＆＃34;方法，我得到代码行的classcastexception

＆＃34; retrieveClubID =（ClubInfo）in.readObject（）;＆＃34;

我非常喜欢新手，我一直在阅读有关施法的内容，而我的理解是我正在尝试进行不兼容的类型转换，但我对修复它感到困惑。 ＆＃34; ClubInfo＆＃34;是我的一个类的名称（见下文），＆＃34; retrieveClubID＆＃34;只是一个对象引用，指向一个无参数的构造函数。

如果有人能澄清我做错了什么，我将非常感激。此外，任何人都可以建议一个网站，它将澄清＆＃34;文件/缓冲/输出＆＃34;之间的差异。流？我正在努力寻找一个能够深入探讨这些流程的网站。

代码段如下。

import java.util.InputMismatchException;
import java.util.Scanner;
import java.io.*;
import java.util.Arrays;

public class ReadClub implements java.io.Serializable 
{
   private static final long serialVersionUID = 1;

    public ReadClub()
    {

    }

    public void tryReadClub(){

     ClubInfo retrieveClubID = new ClubInfo();
     ClubInfo retrieveClubName = new ClubInfo();

     System.out.println("Club ID before is : " + retrieveClubID.getClubID());

     System.out.println("Currently printing blah : " + retrieveClubID);

    String fileName = "/home/cabox/workspace/savedgames/" +  retrieveClubID.getClubID();

    try
      {

         FileInputStream fileIn = new FileInputStream("" + fileName + ".ser");
         ObjectInputStream in = new ObjectInputStream(fileIn);
         retrieveClubID = (ClubInfo) in.readObject();
        // retrieveClubName = (ClubInfo) in.readObject();  

         in.close();
         fileIn.close();

      }catch(IOException i)
      {
         i.printStackTrace();

      System.out.println("Not a valid number");
      return;

      }catch(ClassNotFoundException c)
      {
         System.out.println("Club class not found");
         c.printStackTrace();
        return;
      }

      System.out.println("Saved game loaded...");

      System.out.println("Club Name: " + retrieveClubName.getClubInfo());
      System.out.println("Club ID: " + retrieveClubID.getClubID());


    }

}

public class ClubInfo implements java.io.Serializable
{
  private static final String pound = "GBP";
  private double startingBalance;
  private double currentBalance;  
  private int clubID = 1;
  private static int numberOfClubIDS;

   private String clubTest;
   private static final int[] originalStadiumCapacity = new int[21];
   private static final String[][] club = new String[20][2]; // COLUMN 0 IS CLUBNAME, COLUMN 1 IS STADIUM NAME

   private String division;
   private transient int SSN;

      public ClubInfo()
      {
      }

      public ClubInfo(int clubID)
      {
        this.clubID = clubID;
      }

      public ClubInfo(double startingBalance , double currentBalance , String division)
      {
          this.startingBalance = startingBalance;
          this.currentBalance = currentBalance;  
          this.division = division;
      }


      public String toString()
      {
        return clubTest;
      }

      public int getClubID()
      {
       return clubID;
      }

       public String[][] getClubInfo()
       {
          club[0][0] = "Arsenal";         club[0][1] = "Emirates";
          club[1][0] = "Aston Villa";     club[1][1] = "Villa Park";
          club[2][0] = "Bournemouth";     club[2][1] = "Blah";
          club[3][0] = "Chelsea";         club[3][1] = "Blah";
          club[4][0] = "Crystal Palace";  club[4][1] = "Blah";
          club[5][0] = "Everton";         club[5][1] = "Blah";
          club[6][0] = "Leicester City";  club[6][1] = "Blah";
          club[7][0] = "Liverpool";       club[7][1] = "Blah";
          club[8][0] = "Manchester United"; club[8][1] = "Blah";
          club[9][0] = "Manchester City";   club[9][1] = "Blah";
          club[10][0] = "Newcastle United"; club[10][1] = "Blah";
          club[11][0] = "Norwich City";     club[11][1] = "Blah";
          club[12][0] = "Southampton";      club[12][1] = "Blah";
          club[13][0] = "Stoke City";       club[13][1] = "Blah";
          club[14][0] =  "Sunderland";      club[14][1] = "Blah";
          club[15][0] = "Swansea City";     club[15][1] = "Blah";
          club[16][0] = "Tottenham Hotspur"; club[16][1] = "Blah";
          club[17][0] =  "Watford";           club[17][1] = "Blah";
          club[18][0] = "West Brom";          club[18][1] = "Blah";
          club[19][0] = "West Ham United";    club[19][1] = "Blah";

          return club;
        }

        public int[] getOriginalStadiumCapacity()
        {

            originalStadiumCapacity[0] = 70000;
            originalStadiumCapacity[1] = 30000;
            originalStadiumCapacity[2] = 25000;
            originalStadiumCapacity[3] = 50000;
            originalStadiumCapacity[4] = 20000;
            originalStadiumCapacity[5] = 40000;
            originalStadiumCapacity[6] = 30000;
            originalStadiumCapacity[7] = 50000;
            originalStadiumCapacity[8] = 80000;
            originalStadiumCapacity[9] = 40000;
            originalStadiumCapacity[10] = 70000;
            originalStadiumCapacity[11] = 20000;
            originalStadiumCapacity[12] = 30000;
            originalStadiumCapacity[13] = 30000;
            originalStadiumCapacity[14] = 40000;
            originalStadiumCapacity[15] = 30000;
            originalStadiumCapacity[16] = 60000;
            originalStadiumCapacity[17] = 20000;
            originalStadiumCapacity[18] = 30000;
            originalStadiumCapacity[19] = 40000;

            return originalStadiumCapacity;
        }  
}