Error: Exception in thread AWT-EventQueue-0 java.lang.ClassCastException

Question

是否可以从单个文件中读取不同类型的对象？

Answer 1

Is it possible to read different type objects from a single file..?

当然是！这是证明的输出：

Object: 42                                           // Integer
Object: The quick brown fox jumps over the lazy dog  // String
Object: 42.001                                       // Double

这是用于上述输出的源代码：

public class ObjectSerialization {

    public static void main(String[] args) throws IOException, ClassNotFoundException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(new Integer(42));
        oos.writeObject("The quick brown fox jumps over the lazy dog");
        oos.writeObject(new Double(42.001));
        
        oos.flush();
        oos.close();
        
        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        ObjectInputStream ois = new ObjectInputStream(bais);
        Object o;
        o = ois.readObject();
        System.out.println("Object: " + o);
        o = ois.readObject();
        System.out.println("Object: " + o);
        o = ois.readObject();
        System.out.println("Object: " + o);
    }
}

眼尖的人可能会注意到示例中没有涉及 File，但可以随意调整代码以使用实际文件来确认它 也 有效。