Java基础之序列化对象——将对象写入到文件中（SerializeObjects）

控制台程序。

首先定义一个含有任意不同数据类型域的可序列化类：

 import java.io.Serializable;

 public class Junk implements Serializable {
   private static java.util.Random generator = new java.util.Random();
   private int answer;                                                  // The answer
   private double[] numbers;                                            // Valuable data
   private String thought;                                              // A unique thought
   private static final long serialVersionUID = 9001L;

   public Junk(String thought) {
     this.thought = thought;
     answer = 42;                                                       // Answer always 42

     numbers = new double[3 + generator.nextInt(4)];                    // Array size 3 to 6
     for(int i = 0 ; i < numbers.length ; ++i) {                        // Populate with
       numbers[i] = generator.nextDouble();                             // random values
    }
   }

   @Override
   public String toString() {
     StringBuffer strBuf = new StringBuffer(thought);
     strBuf.append('\n').append(String.valueOf(answer));
     for(int i = 0 ; i < numbers.length ; i++) {
       strBuf.append("\nnumbers[")
             .append(String.valueOf(i))
             .append("] = ")
             .append(numbers[i]);
     }
     return strBuf.toString();
   }
 }

然后使用如下程序能将这个类类型的对象写入到文件中：

 import java.io.*;
 import java.nio.file.*;
 import java.io.IOException;

 public class SerializeObjects {
   public static void main(String[] args) {
     Junk obj1 = new Junk("A green twig is easily bent.");
     Junk obj2 = new Junk("A little knowledge is a dangerous thing.");
     Junk obj3 = new Junk("Flies light on lean horses.");

     Path file = Paths.get(System.getProperty("user.home")).resolve("Beginning Java Struff").resolve("JunkObjects.bin");
     try {
       Files.createDirectories(file.getParent());    // Make sure we have the directory
     } catch (IOException e) {
       e.printStackTrace();
       System.exit(1);
     }

     try (ObjectOutputStream objectOut = new ObjectOutputStream(new BufferedOutputStream(Files.newOutputStream(file)))){
       // Write three objects to the file
       objectOut.writeObject(obj1);                                     // Write object
       objectOut.writeObject(obj2);                                     // Write object
       objectOut.writeObject(obj3);                                     // Write object
       System.out.println("\n\nobj1:\n" + obj1
                         +"\n\nobj2:\n" + obj2
                         +"\n\nobj3:\n" + obj3);

     } catch(IOException e) {
       e.printStackTrace();
     }
   }
 }