java - java中反序列化步骤

Question

 class A extends Serializable{
      public A(){}
int x=0;
      private final transient ReentrantReadWriteLock lock = new ReentrantReadWriteLock();

    }

关于反序列化的几个问题: 1)为什么案例序列化时需要提供默认构造函数？ 2) 为什么反序列化后字段“lock”没有被初始化？

编辑:忘记在我原来的帖子中添加“ transient ”。现在添加它。

Answer 1

1. 不需要

2. 锁被初始化，下面的代码确实打印了初始化的锁(只需将 B 的对象写入字节数组并从中读取)

   public class B implements Serializable {
       private int x = 0;
       private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
   
       public static void main(String[] args) throws IOException, ClassNotFoundException {
           ByteArrayOutputStream bos = new ByteArrayOutputStream();
           try (ObjectOutput out = new ObjectOutputStream(bos)) {
                out.writeObject(new B());
           }
           catch (IOException e) {
               e.printStackTrace();
               throw e;
           }
           byte[] bytes = bos.toByteArray();
   
           ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
           try (ObjectInput in = new ObjectInputStream(bis)) {
               B b = (B) in.readObject();
               System.out.println(b.lock);
           }
           catch (IOException e) {
               e.printStackTrace();
               throw e;
           }
         }
      }
   }