Question

我必须为java项目实现Object Files，但是在加载文件时我遇到了麻烦（保存就可以了）

public static void loadStudentList() {
    boolean endOfFile = false;

    try {
        // create a FileInputStream object, studentFile
        FileInputStream studentFile = new FileInputStream("Students.obf");
        // create am ObjectImnputStream object to wrap around studentStream
        ObjectInputStream studentStream = new ObjectInputStream(studentFile) ;

        // read the first (whole) object with the readObject method
        Student tempStudent = (Student) studentStream.readObject();
        while (endOfFile != true) {
            try {
                tempStudent = (Student) studentStream.readObject();
                stud1.add(tempStudent);
            }
            catch(EOFException e) {
                endOfFile = true;
            }
        }
        studentStream.close();
        //use the fact that the readObject throws an EOFException to check whether the end of eth file has been reached
    }
    catch(FileNotFoundException e) {
        System.out.println("File not found");
    }

    catch(ClassNotFoundException e) {  // thrown by readObject
    /* which indicates that the object just read does not correspond to any class
known to the program */
        System.out.println("Trying to read an object of an unkonown class");
    }
    catch(StreamCorruptedException e) { //thrown by constructor
    // which indicates that the input stream given to it was not produced by an ObjectOutputStream object
        System.out.println("Unreadable File Format");
    }
    catch(IOException e) {
        System.out.println("There was a problem reading the file");
    }
}

这是我用来加载文件的代码。该程序将加载 ONLY 我文件中的最后2条记录。想法是我将所有这些加载到数组列表中以供将来在程序中使用。此外，我没有得到任何回收。有帮助吗？谢谢:)）

Answer 1

为什么不将对象添加到ArrayList<Type>，然后将它们写入/序列化为文件然后读取/反序列化它，将数据读入一个ArrayList<Type>。

然后你可以从ArrayList

逐个获取你的对象

这可能是一种更容易解决问题的方法。

  //Serialize
  ArrayList<Student> students = new ArrayList<Student>();
  //Add the student objects to the array list
  File f = new File("FileName.ser");
  ObjectOutputStream objOut = new ObjectOutputStream(new FileOutputStream(f));
  objOut.writeObject(students);

   //Deserialize
   ArrayList<Student> students = new ArrayList<Student>();
   ObjectInputStream objIn = new ObjectInputStream(new FileInputStream(new File("FileName.ser")));
   students = (ArrayList<String>) objIn.readObject();

Answer 2

您永远不会在列表中添加您读过的第一个学生

Student tempStudent = (Student) studentStream.readObject();
         while (endOfFile != true)
        {
            try
            {

                 tempStudent = (Student) studentStream.readObject();
                 stud1.add(tempStudent);
            }

删除while之前的读取，如下面的代码

     while (endOfFile != true)
    {
        try
        {

             Student tempStudent = (Student) studentStream.readObject();
             stud1.add(tempStudent);
        }

我不确定这是否能解决您的问题

从Java中的文件错误加载？

2 个答案: