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

 1 import java.io.Serializable;
 2 
 3 public class Junk implements Serializable {
 4   private static java.util.Random generator = new java.util.Random();
 5   private int answer;                                                  // The answer
 6   private double[] numbers;                                            // Valuable data
 7   private String thought;                                              // A unique thought
 8   private static final long serialVersionUID = 9001L;
 9 
10   public Junk(String thought) {
11     this.thought = thought;
12     answer = 42;                                                       // Answer always 42
13 
14     numbers = new double[3 + generator.nextInt(4)];                    // Array size 3 to 6
15     for(int i = 0 ; i < numbers.length ; ++i) {                        // Populate with
16       numbers[i] = generator.nextDouble();                             // random values
17    }
18   }
19 
20   @Override
21   public String toString() {
22     StringBuffer strBuf = new StringBuffer(thought);
23     strBuf.append('
').append(String.valueOf(answer));
24     for(int i = 0 ; i < numbers.length ; i++) {
25       strBuf.append("
numbers[")
26             .append(String.valueOf(i))
27             .append("] = ")
28             .append(numbers[i]);
29     }
30     return strBuf.toString();
31   }
32 }

 1 import java.io.*;
 2 import java.nio.file.*;
 3 import java.io.IOException;
 4 
 5 public class SerializeObjects {
 6   public static void main(String[] args) {
 7     Junk obj1 = new Junk("A green twig is easily bent.");
 8     Junk obj2 = new Junk("A little knowledge is a dangerous thing.");
 9     Junk obj3 = new Junk("Flies light on lean horses.");
10 
11     Path file = Paths.get(System.getProperty("user.home")).resolve("Beginning Java Struff").resolve("JunkObjects.bin");
12     try {
13       Files.createDirectories(file.getParent());    // Make sure we have the directory
14     } catch (IOException e) {
15       e.printStackTrace();
16       System.exit(1);
17     }
18 
19     try (ObjectOutputStream objectOut = new ObjectOutputStream(new BufferedOutputStream(Files.newOutputStream(file)))){
20       // Write three objects to the file
21       objectOut.writeObject(obj1);                                     // Write object
22       objectOut.writeObject(obj2);                                     // Write object
23       objectOut.writeObject(obj3);                                     // Write object
24       System.out.println("

obj1:
" + obj1
25                         +"

obj2:
" + obj2
26                         +"

obj3:
" + obj3);
27 
28     } catch(IOException e) {
29       e.printStackTrace();
30     }
31   }
32 }