Java序列化和反序列化是一種用于將Java對象轉換為字節流以便存儲或傳輸的方法。當一個對象被序列化時，它的狀態被寫入到一個字節流中，以便可以在稍后的時間重新創建對象。反序列化是將字節流轉換回對象狀態的過程。 Java序列化和反序列化廣泛用于網絡通信、緩存、持久化等領域。

public class Student implements Serializable {
private String name;
private int age;
private String address;
private transient String password;
// get and set methods
}
public class SerializationDemo {
public static void main(String[] args) {
Student student = new Student();
student.setName("Lucy");
student.setAge(18);
student.setAddress("Beijing");
student.setPassword("123456");
// serialization
try {
FileOutputStream fileOut = new FileOutputStream("student.ser");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(student);
out.close();
fileOut.close();
System.out.println("Serialized data is saved in student.ser");
} catch (IOException e) {
e.printStackTrace();
}
// deserialization
try {
FileInputStream fileIn = new FileInputStream("student.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
Student s = (Student) in.readObject();
in.close();
fileIn.close();
System.out.println("Name: " + s.getName());
System.out.println("Age: " + s.getAge());
System.out.println("Address: " + s.getAddress());
// password will be null because it is marked as transient
System.out.println("Password: " + s.getPassword());
} catch (IOException | ClassNotFoundException e) {
e.printStackTrace();
}
}
}

在上面的代碼中，我們定義了一個Student類，并實現了Serializable接口以便將對象序列化。在序列化過程中，我們將Student對象寫入到一個文件中。在反序列化過程中，我們從該文件中讀取數據并將其轉換為Student對象。在輸出Student對象的屬性時，我們發現transient關鍵字標記的password屬性不會被反序列化。