Java - 序列化 - EOFException 问题

Question

很抱歉今天发布了关于序列化的第二篇文章，修复一个问题导致了另一个问题。

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如此处所述 - Java - Serialization - NotSerializableException Issue - 我有一个包含以下类(class)的项目

Student.java

StudentsCollection.java

Students 创建我的 Student 对象(不言自明)，我的 StudentsCollection() 实例化一个存储我的 Student 对象的 Student 类型列表，当尝试保存/加载对象时，我使用此代码并抛出以下异常:

       /**
         * Open student collection
         */
       public void openCollection(){
          try {
             FileInputStream e = new FileInputStream("students.ser");
             ObjectInputStream inputSteam = new ObjectInputStream(e);
              while(inputSteam.readObject() != null){
                  this.list.add((Students)inputSteam.readObject());
              }
          } catch (FileNotFoundException var3) {
              var3.printStackTrace();
             JOptionPane.showMessageDialog(null, "File not found");
          } catch (IOException var4) {
              var4.printStackTrace();
             JOptionPane.showMessageDialog(null, "IO Exception");
          } catch (ClassNotFoundException var5) {
              var5.printStackTrace();
             JOptionPane.showMessageDialog(null, "Required class not found");
          }
    
       }

并且正在抛出:

java.io.EOFException
    at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2598)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1318)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
    at jdatabase.objects.students.StudentsCollection.openCollection(StudentsCollection.java:558)
    at jdatabase.main.MainController.main(MainController.java:14)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

我只在我的列表中添加了一个 Student 对象，保存列表并重新打开它后，我要求控制台打印出该列表，Student 实际上打印了出来。然而，当我创建多个学生对象并每次将其 ID 加 1 并添加它们时，控制台会按顺序打印所有这些对象，然后重新打印(由于某些奇怪的原因)并最终跳过一些。

如果您需要更多代码，请询问。 saveCollection() 现在工作正常

修改后的代码: /**

     * Open student collection
     */
   public void openCollection(){
      try {
         FileInputStream e = new FileInputStream("students.ser");
         ObjectInputStream inputSteam = new ObjectInputStream(e);
          while((obj = inputSteam.readObject()) != null){
              this.list.add((Students)obj);
          }
      } catch (FileNotFoundException var3) {
          var3.printStackTrace();
         JOptionPane.showMessageDialog(null, "File not found");
      } catch (IOException var4) {
          var4.printStackTrace();
         JOptionPane.showMessageDialog(null, "IO Exception");
      } catch (ClassNotFoundException var5) {
          var5.printStackTrace();
         JOptionPane.showMessageDialog(null, "Required class not found");
      }

   }

抛出:

java.io.EOFException
    at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2598)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1318)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
    at jdatabase.objects.students.StudentsCollection.openCollection(StudentsCollection.java:559)
    at jdatabase.main.MainController.main(MainController.java:13)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

只有 1 个学生对象，控制台中打印以下内容:

Student name: Student Student surname: Default Student ID: 0 Student DoB: 1/1/90

并再次打印:

Student name: Student Student surname: Default Student ID: 0 Student DoB: 1/1/90

Answer 1

readObject() 在流末尾不会返回 null，因此对其进行测试，因为循环终止条件无效。当遇到流结尾时，您的代码正确抛出EOFException。这里没有需要解决的问题。