objectsaver.java

程序练习中包括书中实例程序代码和练习中要用到的代码,是压缩文件

package examples.io;

import java.io.*;

/** A class defined to be used in
  * serialization operations.
  */
class ObjectToSave implements Serializable {

   static final long serialVersionUID
      = 7482918152381158178L;

   private int i;
   private String s;
   private transient double d;

   public ObjectToSave( int i, String s, double d ) {
      this.i = i;
      this.s = s;
      this.d = d;
   }

   public String toString() {
      return "i = " + i + ", s = " + s + ", d = " + d;
   }

   private void readObject( ObjectInputStream ois )
         throws ClassNotFoundException, IOException {
      System.out.println( "deserializing..." );
      ois.defaultReadObject();
      System.out.println( "deserialized" );
   }

   private void writeObject( ObjectOutputStream oos )
         throws IOException {
      System.out.println( "serializing..." );
      oos.defaultWriteObject();
      System.out.println( "serialized" );
   }
}

/** A class used to demonstrate serializing objects
  * to and from a file.
  */
public class ObjectSaver {

   private static final String FILE_NAME
      = "objects.ser";

   /** Test method for the class
     * @param args not used
     */
   public static void main( String[] args ) {
      try {
         // create the object to be serialized
         ObjectToSave ots
            = new ObjectToSave( 57, "pizza", 3.14 );

         // create the target File object and erase
         // any already existing file
         File objectFile = new File( FILE_NAME );
         if ( objectFile.exists() ) {
            objectFile.delete();
         }

         // open the file, create the output stream
         // and write the object
         FileOutputStream fos
            = new FileOutputStream( objectFile );
         ObjectOutputStream oos
            = new ObjectOutputStream( fos );
         oos.writeObject( ots );
         oos.close();

         // reopen the file and retrieve the object
         FileInputStream fis
            = new FileInputStream( objectFile );
         ObjectInputStream ois
            = new ObjectInputStream( fis );
         ObjectToSave retrieved
            = (ObjectToSave) ois.readObject();
         ois.close();

         System.out.println( retrieved );
      }

      catch ( OptionalDataException x ) {
         System.out.println( x );
         x.printStackTrace();
      }
      catch ( ClassNotFoundException x ) {
         System.out.println( x );
         x.printStackTrace();
      }
      catch ( IOException x ) {
         System.out.println( x );
         x.printStackTrace();
      }
   }
}