Java对象的XML序列化和反序列化 - (2)

前一篇文章里写了如何用XMLEncoder和XMLDecoder序列化和反序列化符合JavaBeans规范的对象。那么，如果待序列化的对象不符合JavaBeans规范，比如一个纯数据对象，那会是什么后果？

下面是一个纯数据对象的代码：

public class PureDataObject{   public PureDataObject()   {   }   public PureDataObject(int id, String name, double value, boolean valid)   {      this.id = id;      this.name = name;      this.value = value;      this.valid = valid;   }   public int id;   public String name;   public double value;   public boolean valid;}

下面是演示代码：

import java.beans.XMLDecoder;import java.beans.XMLEncoder;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;public class XmlSerialize{   public XmlSerialize()   {   }   public void serializeSingleObject(OutputStream os, Object obj)       // 序列化单个java对象   {      // XMLEncoder xe = new XMLEncoder(os);      XMLEncoder xe = new XMLEncoder(os, "GBK", true, 0);     // 仅用于Java SE 7      xe.writeObject(obj);    // 序列化成XML字符串      xe.close();   }   public Object deserializeSingleObject(InputStream is)       // 反序列化单个Java对象   {      XMLDecoder xd = new XMLDecoder(is);      Object obj = xd.readObject();       // 从XML序列中解码为Java对象      xd.close();      return obj;   }   public void runPureDataObject()     // 无法正常序列化纯数据对象。   {      File xmlFile = new File("data.xml");      PureDataObject pdo4Out = new PureDataObject();      pdo4Out.id = 1;      pdo4Out.name = "Hello, World !";      pdo4Out.value = 1.414;      pdo4Out.valid = true;      try      {         FileOutputStream ofs = new FileOutputStream(xmlFile);       // 创建文件输出流对象         serializeSingleObject(ofs, pdo4Out);         ofs.close();      } catch (FileNotFoundException e)      {         e.printStackTrace();      } catch (IOException e)      {         e.printStackTrace();      }      try      {         FileInputStream ifs = new FileInputStream(xmlFile);         PureDataObject pdo4In = (PureDataObject)deserializeSingleObject(ifs);         System.out.println("id: " + pdo4In.id);         System.out.println("name: " + pdo4In.name);         System.out.println("value: " + pdo4In.value);         System.out.println("valid: " + pdo4In.valid);      } catch (FileNotFoundException e)      {         e.printStackTrace();      }   }   public static void main(String[] args)   {      XmlSerialize xs = new XmlSerialize();      xs.runSingleObject();      xs.runMultipleObject();      xs.runPureDataObject();   }}

以下是生成的XML文件：

<?xml version="1.0" encoding="GBK"?><java version="1.7.0" class="java.beans.XMLDecoder"> <object class="PureDataObject" id="PureDataObject0">  <void class="PureDataObject" method="getField">   <string>id</string>   <void method="set">    <object idref="PureDataObject0">     <void class="PureDataObject" method="getField">      <string>name</string>      <void method="set">       <object idref="PureDataObject0">        <void class="PureDataObject" method="getField">         <string>value</string>         <void method="set">          <object idref="PureDataObject0">           <void class="PureDataObject" method="getField">            <string>valid</string>            <void method="set">             <object idref="PureDataObject0"/>             <boolean>true</boolean>            </void>           </void>          </object>          <double>1.414</double>         </void>        </void>       </object>       <string>Hello, World !</string>      </void>     </void>    </object>    <int>1</int>   </void>  </void> </object></java> 

再看看反序列化之后屏幕上输出的结果：

id: 1name: Hello, World !value: 1.414valid: true

可以看到，仍旧能够正常地执行XML序列化和反序列化。不过，序列化之后生成的XML文件，看上去实在是一团乱麻。