【问题标题】:Class deserialization - Differences between Jython and Java类反序列化 - Jython 和 Java 之间的差异
【发布时间】:2020-09-04 12:25:19
【问题描述】:

我能够将自定义 JFrame 序列化到数据库中,并且我想反序列化它。
不幸的是,在所谓的反序列化过程中,我遇到了一个我无法解决的错误。

import sys

from java.io import *
from java.lang import Class
from java.sql import *
from methods import *


class MyFrame(JFrame):
    def __init__(self):
        self._title = 'Frame di prova'
        self.setTitle(self._title)
        c = self.getContentPane()

        self._insertN = JTextField(20)
        nameLabelPane, nameFieldPane = incidentPanels(
            JLabel("Nome"), [self._insertN])

        firstBlock = (nameLabelPane, nameFieldPane)

        firstPane = gridPane(firstBlock)

        if self._title.startswith('Modifica'):
            saveBtn = JButton('Modifica')
        else:
            saveBtn = JButton('Salva')

        globalPane = JPanel()
        gridBagger(globalPane, (firstPane, saveBtn))
        c.add(JScrollPane(globalPane))

        self.pack()


SQL_CREATE_TABLE = "create table if not exists serialized_java_objects (object_name varchar(1000), serialized_object blob)"
SQL_SERIALIZE_OBJECT = "INSERT INTO serialized_java_objects(object_name, serialized_object) VALUES (?, ?)"
SQL_DESERIALIZE_OBJECT = "SELECT serialized_object FROM serialized_java_objects limit 1"


def createTable(connection):
    connection.createStatement().executeUpdate(SQL_CREATE_TABLE)

def serializeJavaObjectToDB(connection, objectToSerialize):
    pstmt = connection.prepareStatement(SQL_SERIALIZE_OBJECT)

    pstmt.setString(1, 'Frame di prova')
    pstmt.setObject(2, objectToSerialize)
    pstmt.executeUpdate()
    pstmt.close()

def deSerializeJavaObjectFromDB(connection):
    pstmt = connection.prepareStatement(SQL_DESERIALIZE_OBJECT)
    rs = pstmt.executeQuery()
    rs.next()

    buf = rs.getBytes(1)
    objectIn = None
    if (buf != None):
        objectIn = ObjectInputStream(ByteArrayInputStream(buf))

    deSerializedObject = objectIn.readObject()

    rs.close()
    pstmt.close()

    return deSerializedObject


def getMySqlConnection():
    mysqlConn = None

    mysqlLog_server = "localhost"
    mysqlLog_username = "root"
    mysqlLog_password = ""
    mysqlLog_database = "tuttle"

    properties = Properties()
    properties.put("user", mysqlLog_username)
    properties.put("password", mysqlLog_password)

    url = "jdbc:mysql://" + mysqlLog_server + "/" + mysqlLog_database + \
        "?user=" + mysqlLog_username + "&password=" + mysqlLog_password

    mysqlConn = DriverManager.getConnection(url)
    return mysqlConn


def main(args):
    frame = MyFrame()
    Class.forName("com.mysql.jdbc.Driver")
    connection = getMySqlConnection()
    createTable(connection)

    serializeJavaObjectToDB(connection, frame)
    objFromDatabase = deSerializeJavaObjectFromDB(connection)

    objFromDatabase.setVisible(True)


if __name__ == '__main__':
    main(sys.argv)

错误出现在objFromDatabase = deSerializeJavaObjectFromDB(connection) 行,尤其是deSerializedObject = objectIn.readObject(),如下:

Traceback (most recent call last):
  File "provaSerializzazione.py", line 119, in <module>
    main(sys.argv)
  File "provaSerializzazione.py", line 113, in main
    objFromDatabase = deSerializeJavaObjectFromDB(connection)
  File "provaSerializzazione.py", line 74, in deSerializeJavaObjectFromDB
    deSerializedObject = objectIn.readObject()
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        at java.io.ObjectInputStream.resolveClass(Unknown Source)
        at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
        at java.io.ObjectInputStream.readClassDesc(Unknown Source)
        at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
        at java.io.ObjectInputStream.readObject0(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at java.io.ObjectInputStream.readObject(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
java.lang.ClassNotFoundException: java.lang.ClassNotFoundException: org.python.proxies.__main__$MyFrame$3

奇怪的是,如果您将行 frame = MyFrame() 替换为 frame = JFrame(),则该函数可以正确序列化,没有错误。
反序列化函数似乎不接受 python 类(它又扩展了 JFrame)。 我应该怎么做才能用 jython 语言反序列化我的 MyFrame 类?提前致谢!

【问题讨论】:

  • 看起来不像是反序列化问题。看起来您的 MyFrame 类在类路径中不存在。
  • @OnurBaştürk 那么你建议我怎么做?
  • 好吧,我不使用 Python。因此,我不知道如何将 java 对象导入 python 项目。也许你可以解释你的项目结构和导入机制,然后我会尝试找到一种方法。我先问一下。 MyFrame 是 Java 对象吗?我觉得不是
  • 你说可以将自定义的JFrame对象序列化到数据库中。我认为自定义对象是 MyFrame 对吗?数据库中的数据是什么样的?是JSON格式还是……还有吗?
  • 数据库中的数据类型是BLOB,因为它是一个序列化的对象。它得救了,我为此感到非常自豪。错误发生在反序列化时。 class MyFrame(JFrame) 是一个 Python/Jython 类,它扩展了 Java 的 JFrame 类,这可能对 (Java) 反序列化器没有吸引力。事实上,如果我用f = JFrame() 声明了一个JFrame,那么在整个程序执行过程中不会有任何问题!但我需要类的扩展......

标签: java serialization deserialization jython


【解决方案1】:

您需要使用org.python.util.PythonObjectInputStream 而不是java.io.ObjectInputStream

【讨论】:

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