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: 1
name: Hello, World !
value: 1.414
valid: 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。