tasks a-s

Task/Object-serialization/Java/object-serialization.java

@@ -0,0 +1,60 @@
+import java.io.*;
+
+// classes must implement java.io.Serializable in order to be serializable
+class Entity implements Serializable {
+    // it is recommended to hard-code serialVersionUID so changes to class
+    // will not invalidate previously serialized objects
+    static final long serialVersionUID = 3504465751164822571L;
+    String name = "Entity";
+    public String toString() { return name; }
+}
+
+class Person extends Entity implements Serializable {
+    static final long serialVersionUID = -9170445713373959735L;
+    Person() { name = "Cletus"; }
+}
+
+public class SerializationTest {
+    public static void main(String[] args) {
+        Person instance1 = new Person();
+        System.out.println(instance1);
+
+        Entity instance2 = new Entity();
+        System.out.println(instance2);
+
+        // Serialize
+        try {
+            ObjectOutput out = new ObjectOutputStream(new FileOutputStream("objects.dat")); // open ObjectOutputStream
+
+            out.writeObject(instance1); // serialize "instance1" and "instance2" to "out"
+            out.writeObject(instance2);
+            out.close();
+            System.out.println("Serialized...");
+        } catch (IOException e) {
+            System.err.println("Something screwed up while serializing");
+            e.printStackTrace();
+            System.exit(1);
+        }
+
+        // Deserialize
+        try {
+            ObjectInput in = new ObjectInputStream(new FileInputStream("objects.dat")); // open ObjectInputStream
+
+            Object readObject1 = in.readObject(); // read two objects from "in"
+            Object readObject2 = in.readObject(); // you may want to cast them to the appropriate types
+            in.close();
+            System.out.println("Deserialized...");
+
+            System.out.println(readObject1);
+            System.out.println(readObject2);
+        } catch (IOException e) {
+            System.err.println("Something screwed up while deserializing");
+            e.printStackTrace();
+            System.exit(1);
+        } catch (ClassNotFoundException e) {
+            System.err.println("Unknown class for deserialized object");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+}