Java.io.ObjectOutputStream.writeFields() 方法

package com.codingdict;



import java.io.*;



public class ObjectOutputStreamDemo {



   public static void main(String[] args) {

      double d = 1.59875d;



      try {



         // create a new file with an ObjectOutputStream

         FileOutputStream out = new FileOutputStream("test.txt");

         ObjectOutputStream oout = new ObjectOutputStream(out);



         // write something in the file

         oout.writeObject(new Example());

         oout.flush();

         oout.close();



         // create an ObjectInputStream for the file we created before

         ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.txt"));



         // read an object from the stream and cast it to Example

         Example a = (Example) ois.readObject();



         // print var of a

         System.out.println("" + a.var);

      } catch (Exception ex) {

         ex.printStackTrace();

      }



   }



   static public class Example implements Serializable {

      static int var = 76458;



      // assign a new serialPersistentFields 

      private static final ObjectStreamField[] serialPersistentFields = {

         new ObjectStreamField("var", Integer.TYPE)

      };



      private void readObject(ObjectInputStream in)

         throws IOException, ClassNotFoundException {



         // get the field and assign it at var

         ObjectInputStream.GetField fields = in.readFields();



         // get var

         var = fields.get("var", 0);

      }



      private void writeObject(ObjectOutputStream out) throws IOException {



         // write into the ObjectStreamField array the variable string

         ObjectOutputStream.PutField fields = out.putFields();

         fields.put("var", var);

         out.writeFields();



      }

   }

}