java序列化之后，对象的引用关系？

今天写代码的时候用到序列化，不过突然想到这个问题。

于是写了一些测试代码，得出两个结论。

如果两个对象存在引用关系，比如A引用B。

如果两个对象是各自序列化的，则引用关系不再存在。

如果两个对象是是另一个类对象C的成员，序列化C，反序列化C之后,A和B的引用关系还存在。

我就是做了这个两个实验。

1 node2引用了node1，node2.parent=node1,

序列化和反序列化之后，

发现node2.parent ！=node1。

node2.parent 指向的内存跟node1不同，而是另外在内存生成了一个对象。

2 Tree有两个成员，node1和node2，

node2引用了node1，node2.parent=node1,

序列化和反序列化之后，

node2.parent =node1。

数据结构定义：

class node  implements Serializable
{

/**
*
*/
private static final long serialVersionUID = -8475920991534073160L;
node parent;
int id;
public node(int i)
{
id = i;
parent= null;
}
}

//nodeTree，node1和node2存在引用关系
class nodeTree implements Serializable
{
node node1;
node node2;
public nodeTree()
{
node1 = new node(1);
node2 = new node(2);
node2.parent = node1;
}

public void test()
{
if(node1 ==node2.parent)
System.out.println("node1 = node2.parent!");
else System.out.println("node1 !=node2.parent!");

if(node1.parent == null)
System.out.println("node1's parent is null");
else  System.out.println("node1's parent is "+node1.parent.id);

if(node2.parent == null)
System.out.println("node2's parent is null");
else  System.out.println("node2's parent is "+node2.parent.id);
}
}

测试代码：

public class Serial2
{
//序列化 nodeTree，node1和node2的引用关系存在
public void test() throws IOException, ClassNotFoundException
{
nodeTree tree = new nodeTree();
tree.test();

FileOutputStream fos = new FileOutputStream("temp1.out");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(tree);
oos.flush();
oos.close();

FileInputStream fis = new FileInputStream("temp1.out");
ObjectInputStream oin = new ObjectInputStream(fis);
tree = (nodeTree) oin.readObject();
System.out.println("序列化和反序列化之后");
tree.test();
}

//各自序列化node1和node2，之间的引用关系不存在
public void test2() throws IOException, ClassNotFoundException
{
node node1 = new node(1);
node node2 = new node(2);
node2.parent = node1;

System.out.println(node1.id);
System.out.println(node2.id);

if(node1 ==node2.parent)
System.out.println("node1 = node2.parent!");
else System.out.println("node1 !=node2.parent!");

if(node1.parent == null)
System.out.println("node1's parent is null");
else  System.out.println("node1's parent is "+node1.parent.id);

if(node2.parent == null)
System.out.println("node2's parent is null");
else  System.out.println("node2's parent is "+node2.parent.id);

//序列化
FileOutputStream fos = new FileOutputStream("temp1.out");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(node1);
oos.flush();
oos.close();

fos = new FileOutputStream("temp2.out");
oos = new ObjectOutputStream(fos);
oos.writeObject(node2);
oos.flush();
oos.close();

//反序列化
FileInputStream fis = new FileInputStream("temp1.out");
ObjectInputStream oin = new ObjectInputStream(fis);
node1 = (node) oin.readObject();

fis = new FileInputStream("temp2.out");
oin = new ObjectInputStream(fis);
node2 = (node) oin.readObject();

System.out.println("--------------------------------");
System.out.println("序列化和反序列化之后");
System.out.println(node1.id);
System.out.println(node2.id);

if(node1 ==node2.parent)
System.out.println("node1 = node2.parent!");
else System.out.println("node1 !=node2.parent!");

if(node1.parent == null)
System.out.println("node1's parent is null");
else  System.out.println("node1's parent is "+node1.parent.id);

if(node2.parent == null)
System.out.println("node2's parent is null");
else  System.out.println("node2's parent is "+node2.parent.id);

}

public static void main(String[] args) throws ClassNotFoundException, IOException
{
// TODO Auto-generated method stub
Serial2 test = new Serial2();
//test.test();
test.test2();
}

}

test()的输出结构：

node1 = node2.parent!
node1's parent is null
node2's parent is 1
序列化和反序列化之后
node1 = node2.parent!
node1's parent is null
node2's parent is 1

test2()的输出结果：

1
2
node1 = node2.parent!
node1's parent is null
node2's parent is 1
--------------------------------
序列化和反序列化之后
1
2
node1 !=node2.parent!
node1's parent is null
node2's parent is 1

本文作者:linger

本文链接：http://blog.csdn.net/lingerlanlan/article/details/38087601