Java序列化

Question

我现在正在学习如何使用Java语言进行序列化。我已经阅读了一些关于这个主题的帖子和文档，我试着做一个简单的例子(如下所示)

public class SterializeObject implements java.io.Serializable{

        /**
         * 
         */
        private static final long serialVersionUID = 1L;

        private String name;
        private transient int code;

        public SterializeObject (String n, int c){
            name = n;
            code = c;
        }

        public void printAtributes (){
            System.out.println("name: " + name + "; code: " + code);
        }
    }

    public class MainClass {
        public static void main(String[] agrs) {
            SterializeObject ob1 = new SterializeObject("ana", 1);
            SterializeObject ob2 = new SterializeObject("rita", 2);

            try {
                FileOutputStream fileOut = new FileOutputStream("file.data");
                ObjectOutputStream outObj = new ObjectOutputStream(fileOut);
                outObj.writeObject(ob1);
                outObj.writeObject(ob2);
                outObj.close();
                System.out.println("Objects were serialized!");
            } catch (IOException e) {
                e.printStackTrace();
            }

            ArrayList<SterializeObject> list = new ArrayList<SterializeObject>();
            try {
                FileInputStream fileInput = new FileInputStream("file.data");
                ObjectInputStream inputObj = new ObjectInputStream(fileInput);
                Object o;
                try {
                    while ((o = inputObj.readObject()) != null) {
                        list.add((SterializeObject) o);
                    }
                } catch (ClassNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    System.out.println("Erro foi aqui! (1)");
                }

                inputObj.close();
                fileInput.close();
            } catch (IOException e) {
                e.printStackTrace();
                System.out.println("Erro foi aqui! (2)");
            }

            for (int i = 0; i < list.size(); ++i) {
                list.get(i).printAtributes();
            }
        }
    }

我创建了一个包含两个变量的代码:一个是string ( Class SterializeObject )，另一个是瞬态的int (代码)。然后，在主要部分，我生成了该类的两个实例，并尝试将其写入一个文件中，我已经成功地完成了！在此之后，我尝试使用循环读取两个对象。这就是我的问题。因为ObjectInputStream没有某种方法来判断我们是否结束了。所以，我试着处理这个条件：(o = inputObj.readObject()) != null。

My output is this:
java.io.EOFException
    at java.io.ObjectInputStream$BlockDataInputStream.peekByte(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)
    at MainClass.main(MainClass.java:30)
Objects were serialized!
Erro foi aqui! (2)
name: ana; code: 0
name: rita; code: 0

我得到了对象，但我得到了一个错误，因为，我认为，是试图访问不存在的东西。

有没有人能告诉我其他的方法？

诚挚的问候。

Answer 1

读取与写入对象数量一样多的对象，或者写入对象列表本身，而不是一个接一个地写入每个对象。

(或者依靠EOFException来检测流的结束，但这很难看)。

Answer 2

正如你们许多人告诉我的那样，我创建了一个ArrayList并序列化了ArrayList。我的代码是：

public class MainClass {
    public static void main(String[] agrs) {
        SterializeObject ob1 = new SterializeObject("ana", 1);
        SterializeObject ob2 = new SterializeObject("rita", 2);

        ArrayList <SterializeObject> list = new ArrayList<>();
        list.add(ob1);
        list.add(ob2);

        ArrayList <SterializeObject> input = new ArrayList<SterializeObject>();

        try {
            FileOutputStream fileOut = new FileOutputStream("file.data");
            ObjectOutputStream outObj = new ObjectOutputStream(fileOut);
            outObj.writeObject(list);
            outObj.close();
            System.out.println("Objects were serialized!");
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            FileInputStream fileInput = new FileInputStream("file.data");
            ObjectInputStream inputObj = new ObjectInputStream(fileInput);
            Object o;
            try {
                input = (ArrayList<SterializeObject>) inputObj.readObject();

            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                System.out.println("Erro foi aqui! (1)");
            }

            inputObj.close();
            fileInput.close();
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("Erro foi aqui! (2)");
        }

        for (int i = 0; i < input.size(); ++i) {
            input.get(i).printAtributes();
        }
    }
}

输出结果是:对象已序列化！名称: ana；编码:0名称: rita；编码:0

谢谢你的帮助!

Answer 3

与ObjectOutputStream一起关闭FileOutputStream

fileOut.close();