Question

package edu.uga.cs1302.gui;

import javax.swing.SwingUtilities;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class StudentMain {
    public static void main(String[] args) {
        // this is inside a "lambda" Runnable

        FileOutputStream fos;
        try {
            Student a = new Student("C", "H", 1234, "12-11-1937", "UGA");
            fos = new FileOutputStream("StudentsList.dat");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            a.storeObject(oos);
            System.out.println("success");
            FileInputStream fis = new FileInputStream("StudentsList.dat");
            ObjectInputStream ois = new ObjectInputStream(fis);
            Student b = new Student("B", "H", 8888, "10-22-1936", "UNC");
            b.retrieveObject(ois);
            System.out.println(b.toString());
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

学生班

package edu.uga.cs1302.gui;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.text.ParseException;

public class Student extends Person implements Serializable{

protected String college;
private static final long serialVersionUID = -5047600810798119921L;
public Student(String firstname, String lastname,int ID, String DOB1, String college) throws ParseException{
    super(firstname, lastname,ID, DOB1);
    this.college=college;
}
public void storeObject(ObjectOutputStream out) throws IOException{
    out.writeObject(this);
    out.flush();
}
public void retrieveObject(ObjectInputStream in) throws IOException,     ClassNotFoundException, ParseException{    
            Student temp = (Student) in.readObject();
        System.out.println(temp.toString());
        this.setFirst(temp.getFirst());
        this.setLast(temp.getLast());
        this.setID(temp.getID());
        this.setDOB(temp.getDOB());
        this.setCollege(temp.getCollege());

}
public String getCollege(){
    return college;
}
public void setCollege(String college){
    this.college= college;
}
public String toString(){
    String student = super.getID() + " "+super.getFirst()+" "+super.getLast()+" "+super.getDOB()+" ["+college+"]";
    return student;
}
}

人类

package edu.uga.cs1302.gui;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Person {

public String first;
public String last;
public Date date1;
public int ID;
public String DOB;

public Person(String firstname, String lastname,int ID, String DOB1) throws ParseException{
    this.first=firstname;
    this.last=lastname;
    if(ID>999&&ID<10000){
        this.ID = ID;
    }
    SimpleDateFormat simple = new SimpleDateFormat("MM-dd-yyyy");
    Date date = simple.parse(DOB1); //must parse to get data
    this.date1 = date;
    this.DOB = DOB1;
    //this.DOB = DOB;
}
public String getFirst(){
    return first;
}
public String getLast(){
    return last;
}
public String getDOB(){
    return DOB;
}
public int getID(){
    return ID;
}
public void setFirst(String first){
    this.first = first;
}
public void setLast(String last){
    this.last = last;
}
public void setDOB(String DOB1) throws ParseException{
    SimpleDateFormat simple = new SimpleDateFormat("MM-dd-yyyy");
    Date date = simple.parse(DOB1); //must parse to get data
    this.date1 = date;
}
public void setID(int ID){
    this.ID = ID;
}
public String toString(){
    SimpleDateFormat sim = new SimpleDateFormat("MM-dd-yyyy");
    String date = sim.format(this.date1);//formats to simple format
    String person = ""+ ID + " "+first+" "+last+" "+date;
    return person;
}


}

错误

success
java.io.InvalidClassException: edu.uga.cs1302.gui.Student; no valid constructor
at java.io.ObjectStreamClass$ExceptionInfo.newInvalidClassException(ObjectStreamClass.java:150)
at java.io.ObjectStreamClass.checkDeserialize(ObjectStreamClass.java:790)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1775)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
at edu.uga.cs1302.gui.Student.retrieveObject(Student.java:25)
at edu.uga.cs1302.gui.StudentMain.lambda$0(StudentMain.java:30)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

由于某些未知原因，我的FileInputStream不起作用。文件正在创建，所以我知道FileOutputStream正在运行。但是，在阅读文件时，它无法破译其含义。

Answer 1

如果你有一个不具有无参数构造函数的非可序列化类，你很可能在序列化期间获得InvalidClassException，然后在任何扩展此calss的类中反序列化。解决此问题的方法之一是使用序列化代理模式。

要实现它，您必须在实现Serializable的类中创建一个静态嵌套的SerializationProxy类。 SerializationProxy将表示封闭类的逻辑状态，并将在序列化期间写入字节流而不是原始实例，并且在反序列化期间将创建原始类的实例，该实例在对象图中占据一席之地。

https://dzone.com/articles/serialization-proxy-pattern

http://blog.codefx.org/design/patterns/serialization-proxy-pattern/

Answer 2

您需要将所有对象都可序列化。只需实现Serializable for Person以便可以编写它。实际上，你应该将你的基类标记为可序列化，然后子类将由于继承而自动序列化。

成功 1234 C H 12-11-1937 [UGA] 1234 C H 10-22-1936 [UGA]

FileInputStream错误Java：错误读取文件

2 个答案: