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Anonymous
Как сериализация может получить доступ к методам readObject и writeObject, если они объявлены закрытыми?
Сообщение
Anonymous »
Я читаю
Thinking in Java 4th Edition.
Там описан странный обходной путь для сериализации временных полей:
Код: Выделить всё
import java.io.*;
public class SerializationTest implements Serializable {
private String firstData;
//transient field, shouldn't be serialized.
transient private String secondData;
public SerializationTest(String firstData, String test2) {
this.firstData = firstData;
this.secondData = test2;
}
/**
* Private method, same signature as in Serializable interface
*
* @param stream
* @throws IOException
*/
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(secondData);
}
/**
* Private method, same signature as in Serializable interface
*
* @param stream
* @throws IOException
*/
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException {
stream.defaultReadObject();
secondData = (String) stream.readObject();
}
@Override
public String toString() {
return "SerializationTest{" +
"firstData='" + firstData + '\'' +
", secondData='" + secondData + '\'' +
'}';
}
public static void main(String[] args) throws IOException, ClassNotFoundException {
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try {
fos = new FileOutputStream("object.out");
oos = new ObjectOutputStream(fos);
SerializationTest sTest = new SerializationTest("First Data", "Second data");
oos.writeObject(sTest);
} finally {
oos.close();
fos.close();
}
FileInputStream fis = null;
ObjectInputStream ois = null;
try {
fis = new FileInputStream("object.out");
ois = new ObjectInputStream(fis);
SerializationTest sTest = (SerializationTest) ois.readObject();
System.out.println(sTest);
} finally {
ois.close();
fis.close();
}
//Output:
//SerializationTest{firstData='First Data', secondData='Second data'}
}
}
Как видите, реализованы частные методы writeObject и readObject.
Вопросы:
Для чего ObjectOutputStream и ObjectInputStream используют Reflection для доступа к частным методам?
Сколько подобных лазеек включено в Java?>
Подробнее здесь:
https://stackoverflow.com/questions/568 ... methods-if
1765961589
Anonymous
Я читаю [b]Thinking in Java 4th Edition[/b].
Там описан странный обходной путь для сериализации временных полей:
[code]import java.io.*;
public class SerializationTest implements Serializable {
private String firstData;
//transient field, shouldn't be serialized.
transient private String secondData;
public SerializationTest(String firstData, String test2) {
this.firstData = firstData;
this.secondData = test2;
}
/**
* Private method, same signature as in Serializable interface
*
* @param stream
* @throws IOException
*/
private void writeObject(ObjectOutputStream stream) throws IOException {
stream.defaultWriteObject();
stream.writeObject(secondData);
}
/**
* Private method, same signature as in Serializable interface
*
* @param stream
* @throws IOException
*/
private void readObject(ObjectInputStream stream)
throws IOException, ClassNotFoundException {
stream.defaultReadObject();
secondData = (String) stream.readObject();
}
@Override
public String toString() {
return "SerializationTest{" +
"firstData='" + firstData + '\'' +
", secondData='" + secondData + '\'' +
'}';
}
public static void main(String[] args) throws IOException, ClassNotFoundException {
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try {
fos = new FileOutputStream("object.out");
oos = new ObjectOutputStream(fos);
SerializationTest sTest = new SerializationTest("First Data", "Second data");
oos.writeObject(sTest);
} finally {
oos.close();
fos.close();
}
FileInputStream fis = null;
ObjectInputStream ois = null;
try {
fis = new FileInputStream("object.out");
ois = new ObjectInputStream(fis);
SerializationTest sTest = (SerializationTest) ois.readObject();
System.out.println(sTest);
} finally {
ois.close();
fis.close();
}
//Output:
//SerializationTest{firstData='First Data', secondData='Second data'}
}
}
[/code]
Как видите, реализованы частные методы writeObject и readObject.
Вопросы:
Для чего ObjectOutputStream и ObjectInputStream используют Reflection для доступа к частным методам?
Сколько подобных лазеек включено в Java?>
Подробнее здесь: [url]https://stackoverflow.com/questions/5682269/how-can-serialization-possibly-access-the-readobject-and-writeobject-methods-if[/url]