我代码完成了，但是报错了

package wenjian;

import java.io.*;

public class Test {

public static void main(String[] args) {

Wenjian4 wj41=new Wenjian4(123,"iphone","telephone",4888.0);

Wenjian4 wj42=new Wenjian4(234,"ipad","computer",5088.0);

Wenjian4 wj43=new Wenjian4(345,"macbook","computer",106800.);

Wenjian4 wj44=new Wenjian4(456,"iwatch","watch",4799.0);

try {

FileOutputStream fos=new FileOutputStream("immoc");

ObjectOutputStream oos=new ObjectOutputStream(fos);

oos.writeObject(wj41);

oos.writeObject(wj42);

oos.writeObject(wj43);

oos.writeObject(wj44);

FileInputStream fis=new FileInputStream("immoc");

ObjectInputStream ois=new ObjectInputStream(fis);

Wenjian4 good;

    try {

while((good=(Wenjian4)ois.readObject())!=null) {

System.out.println(good);

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

package wenjian;

import java.io.*;

public class Wenjian4 implements Serializable{

   private int id;

   private String name;

   private String property;

   private double price;

   public Wenjian4(int id,String name,String property,double price) {

   this.setId(id);

   this.setName(name);

   this.setProperty(property);

   this.setPrice(price);

   }

   @Override

public String toString() {

return "Wenjian4 [id=" + id + ", name=" + name + ", property=" + property + ", price=" + price + "]";

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getProperty() {

return property;

}

public void setProperty(String property) {

this.property = property;

}

public double getPrice() {

return price;

}

public void setPrice(double price) {

this.price = price;

}

}