静态成员变量能不能被序列化？？？？

[oyhj_nicholas]

程序如下：

import java.io.*;
class Student implements Serializable
{
private String name;
private transient String password;
private static int count=0;

public Student(String name,String password)
{
System.out.println("调用Student的带参的构造方法");
this.name=name;
this.password=password;
count++;
}
public String toString()
{
return "人数: "+count+" 姓名: "+name+" 密码: "+password;
}
}
public class ObjectSerTest1
{
public static void main(String args[])
{
try{

FileOutputStream fos=new FileOutputStream("test.obj");
ObjectOutputStream oos=new ObjectOutputStream(fos);

Student s1=new Student("张三","12345");
Student s2=new Student("王五","54321");


oos.writeObject(s1);
oos.writeObject(s2);

oos.close();

FileInputStream fis=new FileInputStream("test.obj");
ObjectInputStream ois=new ObjectInputStream(fis);


Student s3=(Student)ois.readObject();
Student s4=(Student)ois.readObject();


System.out.println(s3);
System.out.println(s4);


ois.close();
}
catch(IOException e)
{
e.printStackTrace();
}
catch(ClassNotFoundException e1)
{
e1.printStackTrace();
}
}
}

count为Student的静态成员变量，书上说静态成员不能被序列化，那为什么此程序运行的结果：输出s3和s4时 count为2呢，按理说应该为0才对啊？还是我哪里理解错了，请高手指定，谢谢了

[qybao]

静态成员属于类级别的，所以不能序列化
这里的不能序列化的意思，是序列化信息中不包含这个静态成员域
你这个测试成功，是因为你都在同一个机器（而且是同一个进程），因为你这个jvm已经把count加载进来了，所以你获取的是加载好的count，如果你是传到另一台机器或者你关掉程序重写写个程序读入test.obj，此时因为别的机器或新的进程是重新加载count的，所以count信息就是初始时的信息。

[S1351026]

同意1楼的

[五哥]

静态变量不属于对象，属于类。不能被序列化。还有瞬态的变量也不能被序列化 。

test.obj ,你打开看看 ，里面是没有
private transient String password;
private static int count=0;
这两个属性的 序列化信息的 ，输出2是因为 在当前jvm实例中count = 2 ；

你可以这样测试，写两个类来测试，一个类写入序列化文件， 另外一个类读出序列化文件


如 ：

import java.io.*;

class Student1 implements Serializable {
	private static final long serialVersionUID = 1L;
	private String name;
	private transient String password;
	private static int count = 0;

	public Student1(String name, String password) {
		System.out.println("调用Student的带参的构造方法");
		this.name = name;
		this.password = password;
		count++;
	}

	public String toString() {
		return "人数: " + count + " 姓名: " + name + " 密码: " + password;
	}
}

public class ObjectSerTest1 {
	public static void main(String args[]) {
		try {

			FileOutputStream fos = new FileOutputStream("test.obj");
			ObjectOutputStream oos = new ObjectOutputStream(fos);

			Student1 s1 = new Student1("张三", "12345");
			Student1 s2 = new Student1("王五", "54321");

			oos.writeObject(s1);
			oos.writeObject(s2);

			oos.close();

			FileInputStream fis = new FileInputStream("test.obj");
			ObjectInputStream ois = new ObjectInputStream(fis);

			Student1 s3 = (Student1) ois.readObject();
			Student1 s4 = (Student1) ois.readObject();

			System.out.println(s3);
			System.out.println(s4);

			ois.close();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e1) {
			e1.printStackTrace();
		}
	}
}

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class Test{


	
	public static void main(String args[]){
		
		try {

			FileInputStream fis = new FileInputStream("test.obj");
			ObjectInputStream ois = new ObjectInputStream(fis);

			Student1 s3 = (Student1) ois.readObject();
			Student1 s4 = (Student1) ois.readObject();

			System.out.println(s3);
			System.out.println(s4);

			ois.close();
		} catch (IOException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e1) {
			e1.printStackTrace();
		}
	}
	
    
	
}

[游一游走一走]

执行下下面的代码就可以推翻你的想法了,static不序列化的

import java.io.*;
class Student implements Serializable
{
  private String name;
  private transient String password;
  private static int count=0;
  
  public Student(String name,String password)
  {
  System.out.println("调用Student的带参的构造方法");
  this.name=name;
  this.password=password;
  count++;
  }
  public String toString()
  {
  return "人数: "+count+" 姓名: "+name+" 密码: "+password;
  }
}
public class ObjectSerTest1
{
public static void main(String args[])
{
try{

FileOutputStream fos=new FileOutputStream("test.obj");
ObjectOutputStream oos=new ObjectOutputStream(fos);

Student s1=new Student("张三","12345");
Student s2=new Student("王五","54321");
System.out.println(s1);
System.out.println(s2);

oos.writeObject(s1);
oos.writeObject(s2);

oos.close();

new Student("xyq","i love you");

FileInputStream fis=new FileInputStream("test.obj");
ObjectInputStream ois=new ObjectInputStream(fis);

 
Student s3=(Student)ois.readObject();
Student s4=(Student)ois.readObject();
 
 
System.out.println(s3);
System.out.println(s4);
 
 
ois.close();
}
catch(IOException e)
{
e.printStackTrace();
}
catch(ClassNotFoundException e1)
{
e1.printStackTrace();
}
}
}