在java中使用XMLEncoder序列化

Question

经过一个小时的wikis和在Java中使用XMLEncoder的惯例之后，我仍然无法在使用XMLEncoder序列化SystemSnapshot类方面取得任何进展。有人能告诉我出了什么问题吗？我的资源如下：

package core;

import gui.SceneManager;
import java.io.Serializable;

/**
 *
 * @author Subhra
*/

public class SystemSnapshot implements Serializable{

private static final long serialVersionUID = -6637378268413872760L;

private final School school;

private final User[] users;

private final String colorName;

public SystemSnapshot(){
    school = SessionManager.getSchool();
    users = UserStore.getUsers();
    colorName = SceneManager.getColor();
}

public SystemSnapshot(School school, User[] users, String c) {
    this.school = school;
    this.users = users;
    this.colorName = c;
}

public School getSchool() {
    return school;
}

public User[] getUsers() {
    return users;
}

public String getColorName() {
    return colorName;
}

}

终端没有错误。但是输出如下：

<?xml version="1.0" encoding="UTF-8"?>
<java version="1.8.0_40" class="java.beans.XMLDecoder">
<object class="core.SystemSnapshot"/>
</java>

有没有人？

在jtahlborn的回答之后，我计算出并添加了所有的getter和setter。现在我得到两种类型的输出。案例1：

XMLEncoder xml = new XMLEncoder(new FileOutputStream("try.xml"));
School ss = new School("S");
ss.addSubject(new Subject("BEnals"));
ss.addTeacher(new Teacher("Nil","T0",21,5000,new Subject("S")));
ss.addClass(new Standard(1,1));
ss.addStudent("STU0");
User u = new User(UserType.ADMIN,"Subhra","subhra","itsveryconfidential");
SystemSnapshot ss2 = new SystemSnapshot(ss,new User[]{u},"A string");
xml.writeObject(ss2);
xml.close();

正在产生正确的输出。鉴于案例2：

XMLEncoder oos = new XMLEncoder(new FileOutputStream("data.base"));
SystemSnapshot ss = new   SystemSnapshot(SessionManager.getSchool(),UserStore.getUsers(),SceneManager.getColor());
oos.writeObject(ss);
oos.close();

仍在产生上述输出。该怎么办呢？

SessionManager 和 UserStore的源代码

SessionManager.java

package core;

import core.User.UserType;
public class SessionManager {

private static User currentuser;

private static School school;

public static void setSchool(School schol) {
     school = schol;
}

public static School getSchool() {
    return school;
}

public static User getCurrentuser() {
    return currentuser;
}

public static void setCurrentuser(User currentuser) {
    SessionManager.currentuser = currentuser;
}

public static UserType getCurrentUserType(){
    return currentuser.getType();
}

}

UserStore.java

package core;

public class UserStore {

private static User[] users = new User[0];

public static User[] getUsers() {
    return users;
}

public static void setUsers(User[] users) {
    UserStore.users = users;
}

public static void addUser(User u) {
    users = new BIO<User>().addToArray(users,u);
}

public static void removeUser(User u) {
    users = new BIO<User>().removeFromArray(users,u);
}

public static User getUser(String username){
    for(User u : users){
        if(u.getUsername().equals(username)){
            return u;
        }
    }
    return null;
}

}

怎么了？

Answer 1

我猜您的SystemSnapshot不是一个有效的java，因为它没有属性的setter。XMLEncoder不像普通序列化那样神奇，它需要有效的java (getter和setter用于所有属性)。