java 反序列化时对象的static属性序列化问题。

代码仅供自己参考。

package com.zhi.learnj;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class StoreCadState {
	
	public static void main(String[] args) throws Exception {
		
		List<Class<? extends Shape>> shapeTypes = new ArrayList<>();
		shapeTypes.add(Circle.class);
		shapeTypes.add(Square.class);
		shapeTypes.add(Line.class);
		
		List<Shape> shapes = new ArrayList<>();
		System.out.println("random generate ten shapes");
		for(int i=0; i<10; i++){
			shapes.add(Shape.randomFactory());
		}
		System.out.println("set color of all shapes to GREEN");
		for(int i=0; i<10; i++){
			shapes.get(i).setColor(Shape.GREEN);
		}
		
		ObjectOutputStream oos = new ObjectOutputStream(
				new FileOutputStream("cadstore.txt"));
		oos.writeObject(shapeTypes);
		Line.serializeStaticState(oos);
		oos.writeObject(shapes);
		
		oos.close();
		System.out.println(shapes);
	}
	/**
random generate ten shapes
set color of all shapes to GREEN
[class com.zhi.learnj.Circle, color=3, xPos=58, yPos=55, dimension=93
, class com.zhi.learnj.Square, color=3, xPos=61, yPos=61, dimension=29
, class com.zhi.learnj.Line, color=3, xPos=68, yPos=0, dimension=22
, class com.zhi.learnj.Circle, color=3, xPos=7, yPos=88, dimension=28
, class com.zhi.learnj.Square, color=3, xPos=51, yPos=89, dimension=9
, class com.zhi.learnj.Line, color=3, xPos=78, yPos=98, dimension=61
, class com.zhi.learnj.Circle, color=3, xPos=20, yPos=58, dimension=16
, class com.zhi.learnj.Square, color=3, xPos=40, yPos=11, dimension=22
, class com.zhi.learnj.Line, color=3, xPos=4, yPos=83, dimension=6
, class com.zhi.learnj.Circle, color=3, xPos=75, yPos=10, dimension=42
]

	 */
	
	public static class RecoverCadState{
		@SuppressWarnings("unchecked")
		public static void main(String[] args) throws Exception {
			Square square = new Square(-1, -1, -1);
			square.setColor(Shape.RED);
			//如果不注释掉上面代码，Sqaure color = RED. 
			// 之前看书的时候没有注意到这部分。Class对象在一个jvm 中是唯一的，因此，在反序列化对象的时候，对象的static属性的值是当前jvm 中Class相关的static 值。
			// 如Squre.color = RED;  因此在反序列化后，Squre 对象中所有的color 都是RED
			
			ObjectInputStream ois = new ObjectInputStream(
					new FileInputStream("cadstore.txt"));
			List<Class<? extends Shape>> shapeTypes = (List<Class<? extends Shape>>) List.class.cast(ois.readObject());
			Line.deserializeStaticState(ois);
			List<Shape> shapes = (List<Shape>) List.class.cast(ois.readObject());
			System.out.println(shapes);
			
		}
	}

}

abstract class Shape implements Serializable{
	public static final int RED = 1, BLUE = 2, GREEN = 3;
	private static Random rand = new Random(47);
	private static int counter = 0;
	
	private int xPos, yPos, dimension;

	public Shape(int xPos, int yPos, int dimension){
		this.xPos = xPos;
		this.yPos = yPos;
		this.dimension = dimension;
	}
	
	public static Shape randomFactory(){
		int xPos = rand.nextInt(100);
		int yPos = rand.nextInt(100);
		int dimension = rand.nextInt(100);
		
		switch(counter++ % 3){
		default:
		case 0: return new Circle(xPos, yPos, dimension);
		case 1: return new Square(xPos, yPos, dimension);
		case 2: return new Line(xPos, yPos, dimension);
		}
	}
	
	public abstract void setColor(int newColor);
	public abstract int getColor();
	
	@Override
	public String toString() {
		return getClass()+", color="+getColor()+", xPos="+xPos+", yPos="+yPos+", "
				+ "dimension="+dimension+"\n";
	}

}
class Line extends Shape{
	private static int color = RED;
	
	public Line(int xPos, int yPos, int dimension) {
		super(xPos, yPos, dimension);
	}
	
	public static void serializeStaticState(ObjectOutputStream oos) 
			                                                      throws IOException{
		oos.writeInt(color);
	}
	
	public static void deserializeStaticState(ObjectInputStream ois)
	                                                               throws IOException{
		color = ois.readInt();
	}

	@Override
	public void setColor(int newColor) {
		color = newColor;
	}

	@Override
	public int getColor() {
		return color;
	}
	
}
class Square extends Shape{
	private static int color;
	
	public Square(int xPos, int yPos, int dimension) {
		super(xPos, yPos, dimension);
		color = RED;
	}

	@Override
	public void setColor(int newColor) {
		color = newColor;
	}

	@Override
	public int getColor() {
		return color;
	}
}

class Circle extends Shape{
	private static int color = RED;

	public Circle(int xPos, int yPos, int dimension) {
		super(xPos, yPos, dimension);
	}

	@Override
	public void setColor(int newColor) {
		color = newColor;
	}

	@Override
	public int getColor() {
		return color;
	}
	
}