1
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();
}
}
}
學生班級的FileInputStream錯誤的Java：讀取文件錯誤
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;
}
}
Person類
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;
}
}
錯誤
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)
一些未知的原因，我的FileInputStream是行不通的。該文件正在創建，所以我知道FileOutputStream正在工作。但是，在閱讀文件時，它無法破譯意義。
嘗試添加一個空的構造函數'Student'類。 – Eric
你可以在一個空的構造函數中，但是如果適用，你可能想使用Person的構造函數，因爲整個繼承點就是擴展已經存在的元素。 – DejaVuSansMono
您添加了異常跟蹤，這很好。現在你必須看看它。當你這樣做時，你會發現問題不是* FileInputStream而是ObjectInputStream。當你查看[InvalidClassException]的[docs]（http://docs.oracle.com/javase/8/docs/api/java/io/InvalidClassException.html）時，你會知道在你的目錄中尋找什麼碼。或者你可以關注* Erik Kralj *的建議。 – kdgregory