什么是 java 序列化？什么情况下需要序列化？序列化的代码示例

Java序列化是指将一个对象转换成一个字节流，以便可以将其存储在文件中、通过网络传输或在进程之间传递。序列化可以用来保存对象的状态，以便可以在以后的时间重建该对象，而无需重新创建它。需要序列化的情况包括：网络传输，对象持久化，进程之间通信等。

以下是Java序列化的代码示例：

import java.io.*;

public class SerializationDemo {
   public static void main(String[] args) {
      // Serialize object
      Student student = new Student("Tom", "M", 23);

      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 file");
      } catch (IOException i) {
         i.printStackTrace();
      }

      // Deserialize object
      try {
         FileInputStream fileIn = new FileInputStream("student.ser");
         ObjectInputStream in = new ObjectInputStream(fileIn);
         Student deserializedStudent = (Student) in.readObject();
         in.close();
         fileIn.close();
         System.out.println("Deserialized data:");
         System.out.println("Name: " + deserializedStudent.getName());
         System.out.println("Gender: " + deserializedStudent.getGender());
         System.out.println("Age: " + deserializedStudent.getAge());
      } catch (IOException i) {
         i.printStackTrace();
      } catch (ClassNotFoundException c) {
         System.out.println("Student class not found");
         c.printStackTrace();
      }
   }
}

class Student implements Serializable {
   private String name;
   private String gender;
   private int age;

   public Student(String name, String gender, int age) {
      this.name = name;
      this.gender = gender;
      this.age = age;
   }

   public String getName() {
      return name;
   }

   public String getGender() {
      return gender;
   }

   public int getAge() {
      return age;
   }
}