以防妳不知道
上面那個Example 2是超連結
點下去可以看到一個跟妳要寫的九分類似的程式原始碼
拿來改會比較快

其實我這個程式碼基本上能改的應該只有AccountFile的那個地方，後來有用樓上那個例子RUN出來~ 還是很感謝大大

有RUN出來就選個最佳解答結案囉...

有阿~ 上一篇解決了~所以我再建一個AccountFile的意思嗎?

那你這篇為何會犯上一篇的錯。
還是只是解決你程式不會出問題。
但你根本不懂怎麼解決。

我用絕對路徑還是不可以....

但是上面那個怎麼改還是無法.........
用絕對路徑也無法

我後來用下面這個例子是成功的~
程式碼1:

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author User
 */
public class Student implements Serializable {
    public Student (String s,short e,short m,short j){
        name=s;
        EScore=e;
        MScore=m;
        JScore=j;
    }
    
    public Student(){}
    
    public String getN(){return name;}
    public Short getE(){return EScore;}
    public Short getM(){return MScore;}
    public Short getJ(){return JScore;}
    
    public double getAvg(){
        return(EScore+MScore+JScore);
    }
    private String name;
    private short EScore;
    private short MScore;
    private short JScore;
    
}````

---

程式碼2:
````import java.io.*;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author User
 */
public class WriteObject {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        // TODO code application logic here
        
        System.out.println("請輸入要建立的學生成績檔檔名");
        System.out.print("➡");
        
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String filename=br.readLine();
        ObjectOutputStream os=new ObjectOutputStream(new FileOutputStream(filename));
        
        String str=new String();
        int counter=0;
        
        do{
            counter++;
            
            System.out.print("請輸入學生姓名:");
            String name=br.readLine();
            
            System.out.print("請輸入英文分數:");
            str=br.readLine();
            short e=Short.parseShort(str);
            
            System.out.print("請輸入數學分數:");
            str=br.readLine();
            short m=Short.parseShort(str);
            
            System.out.print("請輸入Java分數:");
            str=br.readLine();
            short j=Short.parseShort(str);
            
            Student ss=new Student(name,e,m,j);
            
            os.writeObject(ss);
            
            System.out.print("還要輸入另外一筆資料嗎(y/n)");
            
            str=br.readLine();
            
        }while(str.equalsIgnoreCase("Y"));
        
        os.flush();
        os.close();
        
        System.out.println("\n已寫入"+counter+"筆學生資料至檔案"+filename);
        
    }
    
}

ObjectStream File  FileReader/FileWriter

程式碼3:

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author User
 */
public class ReadObject {
    public static void main(String[] args) throws IOException,ClassNotFoundException {
        // TODO code application logic here
        
        System.out.println("要讀取的學生成績檔檔名");
        System.out.print("➡");
        
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String filename=br.readLine();
        
        int counter=0;
        double Esum=0;
        double Msum=0;
        double Jsum=0;
        Student ss=new Student();
        
        System.out.println("姓名\t英文\t數學\tJava\t平均");
        System.out.println("-------------------------------------");
        
        try(ObjectInputStream ois=
                new ObjectInputStream(new FileInputStream(filename))){
         while(true){
                ss=(Student)ois.readObject();
                counter++;
                
                Esum +=ss.getE();
                Msum +=ss.getM();
                Jsum +=ss.getJ();
               System.out.println(ss.getN()+'\t'+ss.getE()+'\t'
                       +ss.getM()+'\t'+ss.getJ()+'\t'
                       +ss.getAvg()); 
                
            }
        }
      catch(EOFException e){
          System.out.println("\n已從檔案"+filename+"讀取"+counter+"筆學生資料");
          System.out.println("\n全員英文平均"+(Esum/counter));
          System.out.println("\n全員數學平均"+(Msum/counter));
          System.out.println("\n全員JAVA平均"+(Jsum/counter));
      }  
}
}