XStream使用

Posted 2020-09-18 北城故事

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Xstream使用：

(1)Xstream介绍

Xstream是一种OXMapping 技术，是用来处理XML文件序列化的框架,在将JavaBean序列化，或将XML文件反序列化的时候，不需要其它辅助类和映射文件，使得XML序列化不再繁索。Xstream也可以将JavaBean序列化成Json或反序列化，使用非常方便。

(2)Xstream的简单例子

　　实例1：

class Person//JavaBean实体类
{
	private String name;
	private int age;
	public Person(String name,int age)
	{
		this.name=name;
		this.age=age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream();
		//XML序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//XML反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
		
		xstream = new XStream(new JettisonMappedXmlDriver());
		xstream.setMode(XStream.NO_REFERENCES);
		//Json序列化
		String json=xstream.toXML(bean);
		System.out.println(json);
		//Json反序列
		bean=(Person)xstream.fromXML(json);
		System.out.println(bean);
	}
}

程序运行结果：　

<test.Person>
  <name>张三</name>
  <age>19</age>
</test.Person>
Person [name=张三, age=19]
{"test.Person":{"name":"张三","age":19}}
Person [name=张三, age=19

　　实例2：

package com.xstream.xml;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.thoughtworks.xstream.XStream;

public class Test {

	public static void main(String[] args) {
		Person p = new Person("小名", 13);
		Person p1= new Person("小红", 12);
		Person p2 = new Person("小花", 11);
		List<Person> list = new ArrayList();
		list.add(p);
		list.add(p1);
		list.add(p2);
		Persons per = new Persons(list);
		XStream xs = new XStream();
		xs.addImplicitCollection(Persons.class, "list");//省略集合根节点
		xs.alias("person", Person.class);//为类名节点重命名
		xs.alias("persons", Persons.class);
		//序列化为xml
		String xml = xs.toXML(per);
		System.out.println("序列化结果：");
		System.out.println(xml);
		//反序列化为对象
		System.out.println("反序列化结果：");
		per= (Persons) xs.fromXML(xml);
		System.out.println(per.getList());
	}
}

package com.xstream.xml;

public class Person {
	
	private String name;
	private int age;
	
	public Person(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	@Override
	public String toString() {
		return "Person [name=" + name + ", age=" + age + "]";
	}
	
}

package com.xstream.xml;

import java.util.List;

public class Persons {
	
	private List list;

	public Persons(List<Person> list) {
		
		this.list = list;
	}

	public List getList() {
		return list;
	}

	public void setList(List list) {
		this.list = list;
	}
}

程序运行结果:

    序列化结果：
<persons>
  <person>
    <name>小名</name>
    <age>13</age>
  </person>
  <person>
    <name>小红</name>
    <age>12</age>
  </person>
  <person>
    <name>小花</name>
    <age>11</age>
  </person>
</persons>
反序列化结果：
[Person [name=小名, age=13], Person [name=小红, age=12], Person [name=小花, age=11]]

2.Xstream的基本使用

(1)Xstream序列化XML

Xstream序列化XML时可以允许用户使用不同的XML解析器，用户可以使用一个标准的JAXP DOM解析器或自Java6集成StAX解析器。这样用户就不需要依赖xpp3-[version].jar。

Xstream序列化XML时，也可以对XML节点重命名。

public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		//XStream xstream = new XStream();//需要XPP3库
		//XStream xstream = new XStream(new DomDriver());//不需要XPP3库
		XStream xstream = new XStream(new StaxDriver());//不需要XPP3库开始使用Java6 
		xstream.alias("人",Person.class);//为类名节点重命名
		//XML序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//XML反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}

　程序运行结果：

<人><name>张三</name><age>19</age></人>
Person [name=张三, age=19]

(2)Xstream序列化Json

Xstream序列化Json与序列化XML类似，例如：

public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream(new JettisonMappedXmlDriver());//设置Json解析器
        xstream.setMode(XStream.NO_REFERENCES);//设置reference模型,不引用
		xstream.alias("人",Person.class);//为类名节点重命名
		//Json序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//Json反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}    

结果：
{"人":{"name":"张三","age":19}}
Person [name=张三, age=19]

3.Xstream序列化重命名

(1)为包重命名：Xstream.aliasPackage()方法

public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream();
		xstream.aliasPackage("com.lzw", "test");//为包名称重命名
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}


    程序运行结果：
<com.lzw.Person>
  <name>张三</name>
  <age>19</age>
</com.lzw.Person>
Person [name=张三, age=19]

(2)为类重命名：Xstream.alias()方法

public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream();
		xstream.alias("人", Person.class);//为类名节点重命名
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
    <人>
      <name>张三</name>
      <age>19</age>
    </人>
    Person [name=张三, age=19]

(3)为字段重命名：Xstream.aliasField()方法　

public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream();
		xstream.aliasField("姓名", Person.class,"name");//为类的字段节点重命名
		xstream.aliasField("年龄", Person.class,"age");//为类的字段节点重命名
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
    <test.Person>
      <姓名>张三</姓名>
      <年龄>19</年龄>
    </test.Person>
    Person [name=张三, age=19]

(4)省略集合根节点：Xstream.addImplicitCollection()方法

class Person
{
	private String name;
	private int age;
	private List friends;
	public Person(String name, int age, String... friends)
	{
		this.name = name;
		this.age = age;
		this.friends = Arrays.asList(friends);
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
	}
}
public class Test
{
	public static void main(String[] args)
	{
		Person bean =new Person("张三",19,"李四","王五","赵六");
		XStream xstream = new XStream();
		xstream.addImplicitCollection(Person.class, "friends");//省略集合根节点
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
    <test.Person>
      <name>张三</name>
      <age>19</age>
      <string>李四</string>
      <string>王五</string>
      <string>赵六</string>
    </test.Person>
    Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(5)把字段节点设置成属性：Xstream.useAttributeFor()方法

public class Test
{
	public static void main(String[] args)
	{
		Person bean =new Person("张三",19,"李四","王五","赵六");
		XStream xstream = new XStream();
		xstream.useAttributeFor(Person.class, "name");//把字段节点设置成属性
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
    <test.Person name="张三">
      <age>19</age>
      <friends class="java.util.Arrays$ArrayList">
        <a class="string-array">
          <string>李四</string>
          <string>王五</string>
          <string>赵六</string>
        </a>
      </friends>
    </test.Person>
    Person [name=张三, age=19, friends=[李四, 王五, 赵六]

(6)隐藏字段：xstream.omitField()方法

public class Test
{
	public static void main(String[] args)
	{
		Person bean =new Person("张三",19,"李四","王五","赵六");
		XStream xstream = new XStream();
		xstream.omitField(Person.class, "friends");//把字段节点隐藏
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
    <test.Person>
      <name>张三</name>
      <age>19</age>
    </test.Person>
    Person [name=张三, age=19, friends=null]

4.Xstream注解的使用　　

(1)设置Xstream应用注解

使用Xstream注解前需要对Xstream进行配置，可以使用两种方式：应用某个JavaBean类的注解或自动使用JavaBean类的注解。代码如下：

XStream xstream = new XStream();
xstream.processAnnotations(Person.class);//应用Person类的注解
xstream.autodetectAnnotations(true);//自动检测注解

(2)重命名注解：@XStreamAlias()

@XStreamAlias("人")
class Person
{
	@XStreamAlias("姓名")
	private String name;
	@XStreamAlias("年龄")
	private int age;
	@XStreamAlias("朋友")
	private List friends;
	public Person(String name, int age, String... friends)
	{
		this.name = name;
		this.age = age;
		this.friends = Arrays.asList(friends);
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
	}
}
    程序运行结果：
    <人>
      <姓名>张三</姓名>
      <年龄>19</年龄>
      <朋友 class="java.util.Arrays$ArrayList">
      <a class="string-array">
          <string>李四</string>
          <string>王五</string>
          <string>赵六</string>
      </a>
      </朋友>
    </人>
    Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(3)省略集合根节点：@XStreamImplicit

class Person
{
	private String name;
	private int age;
	//@XStreamImplicit//只隐藏集合根节点
	@XStreamImplicit(itemFieldName="朋友")//设置重复的节点名，可能会导致无法反序列化
	private List<String> friends;
	public Person(String name, int age, String... friends)
	{
		this.name = name;
		this.age = age;
		this.friends = Arrays.asList(friends);
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
	}
}
    程序运行结果：
<test.Person>
  <name>张三</name>
  <age>19</age>
  <朋友>李四</朋友>
  <朋友>王五</朋友>
  <朋友>赵六</朋友>
</test.Person>
Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(4)把字段节点设置成属性：@XStreamAsAttribute

class Person
{
	@XStreamAsAttribute
	private String name;
	@XStreamAsAttribute
	private int age;
	private List<String> friends;
	public Person(String name, int age, String... friends)
	{
		this.name = name;
		this.age = age;
		this.friends = Arrays.asList(friends);
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
	}
}
    程序运行结果：
<test.Person name="张三" age="19">
  <friends class="java.util.Arrays$ArrayList">
    <a class="string-array">
      <string>李四</string>
      <string>王五</string>
      <string>赵六</string>
    </a>
  </friends>
</test.Person>
Person [name=张三, age=19, friends=[李四, 王五, 赵六]]

(5)隐藏字段：@XStreamOmitField　　

class Person
{
	private String name;
	private int age;
	@XStreamOmitField
	private List<String> friends;
	public Person(String name, int age, String... friends)
	{
		this.name = name;
		this.age = age;
		this.friends = Arrays.asList(friends);
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", friends=" + friends + "]";
	}
}
    程序运行结果：
<test.Person>
  <name>张三</name>
  <age>19</age>
</test.Person>
Person [name=张三, age=19, friends=null]

(6)设置转换器：@XStreamConverter()

class Person
{
	private String name;
	private int age;
        @XStreamConverter(value=BooleanConverter.class,booleans={false},strings={"男","女"})
	private boolean sex;
	public Person(String name, int age, boolean sex)
	{
		this.name = name;
		this.age = age;
		this.sex=sex;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + ", sex=" + sex + "]";
	}
}
    程序运行结果：
<test.Person>
  <name>张三</name>
  <age>19</age>
  <sex>男</sex>
</test.Person>
Person [name=张三, age=19, sex=true]

5.Xstream自定义的转换器

(1)Xstream自带的转换器

Xstream内部有许多转换器，用于JavaBean对象到XML或Json之间的转换。这些转换器的详细信息网址：http://xstream.codehaus.org/converters.html

(2)使用自定义的转换器　　

class Person
{
	private String name;
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
	public String getName()
	{
		return name;
	}
	public void setName(String name)
	{
		this.name = name;
	}
	public int getAge()
	{
		return age;
	}
	public void setAge(int age)
	{
		this.age = age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class PersonConverter implements Converter 
{
	@Override//定义转换器能转换的JavaBean类型
	public boolean canConvert(Class type)
	{
		return type.equals(Person.class);
	}
	@Override//把对象序列化成XML或Json
	public void marshal(Object value, HierarchicalStreamWriter writer, 
MarshallingContext context)
	{
		Person person = (Person) value;
        writer.startNode("姓名");
        writer.setValue(person.getName());
        writer.endNode();
        writer.startNode("年龄");
        writer.setValue(person.getAge()+"");
        writer.endNode();
        writer.startNode("转换器");
        writer.setValue("自定义的转换器");
        writer.endNode();
	}
	@Override//把XML或Json反序列化成对象
	public Object unmarshal(HierarchicalStreamReader reader, 
UnmarshallingContext context)
	{
		   Person person = new Person("",-1);
           reader.moveDown();
           person.setName(reader.getValue());
           reader.moveUp();
           reader.moveDown();
           person.setAge(Integer.parseInt(reader.getValue()));
           reader.moveUp();
           return person;
	}
}
public class Test
{
	public static void main(String[] args)
	{
		Person bean =new Person("张三",19);
		XStream xstream = new XStream();
		xstream.registerConverter(new PersonConverter());//注册转换器
		//序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
<test.Person>
  <姓名>张三</姓名>
  <年龄>19</年龄>
  <转换器>自定义的转换器</转换器>
</test.Person>
Person [name=张三, age=19]

(3)常用的转换器接口与抽象类

SingleValueConverter：单值转换接口

AbstractSingleValueConverter：单值转换抽象类

Converter：常规转换器接口

6.Xstream对象流的使用

(1)Xstream对象输出流

class Person
{
	private String name;
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
}
public class Test
{
	public static void main(String[] args) throws IOException
	{		
		XStream xstream = new XStream();
		ObjectOutputStream out = xstream.createObjectOutputStream(System.out);
		out.writeObject(new Person("张三",12));
		out.writeObject(new Person("李四",19));
		out.writeObject("Hello");
		out.writeInt(12345);
		out.close();
	}
}
    程序运行结果：
<object-stream>
  <test.Person>
    <name>张三</name>
    <age>12</age>
  </test.Person>
  <test.Person>
    <name>李四</name>
    <age>19</age>
  </test.Person>
  <string>Hello</string>
  <int>12345</int>
</object-stream>

注意：XStream对象流是通过标准java.io.ObjectOutputStream和java.io.ObjectInputStream对象。因为XML文档只能有一个根节点,必须包装在一个序列化的所有元素额外的根节点。这个根节点默认 < object-stream > 上面的例子所示。

(2)Xstream对象输出流

class Person
{
	private String name;
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class Test
{
	public static void main(String[] args) throws IOException, ClassNotFoundException
	{
		String s="<object-stream><test.Person><name>张三</name><age>12</age></test.Person><int>12345</int></object-stream>";
		StringReader reader = new StringReader(s);
		XStream xstream = new XStream();
		ObjectInputStream in = xstream.createObjectInputStream(reader);
		System.out.println((Person) in.readObject());
		System.out.println(in.readInt());
	}
}
    程序运行结果：
Person [name=张三, age=12]
12345

7.Xstream持久化API

(1)保存JavaBean对象　　

class Person
{
	private String name;
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class Test
{
	public static void main(String[] args) throws IOException, ClassNotFoundException
	{
		PersistenceStrategy strategy = new FilePersistenceStrategy(new File("D:\\\\tmp"));
		List list = new XmlArrayList(strategy);
		list.add(new Person("张三",13));//保存数据
		list.add(new Person("李四",21));
		list.add(new Person("王五",17));
	}
}

程序运行结果：如果我们检查D:\\tmp目录,有三个文件:int@0.xml、int@1.xml、int@2.xml；每个对象都被序列化到XML文件里。

(2)读取并删除JavaBean对象　　

public class Test
{
	public static void main(String[] args) throws IOException, ClassNotFoundException
	{
		PersistenceStrategy strategy = new FilePersistenceStrategy(new File("D:\\\\tmp"));
		List list = new XmlArrayList(strategy);
		for (Iterator it = list.iterator(); it.hasNext();)
		{
			System.out.println((Person) it.next());
			it.remove();//删除对象序列化文件
		}
	}
}
    程序运行结果：
Person [name=张三, age=13]
Person [name=李四, age=21]
Person [name=王五, age=17]

8.Xstream操作Json

(1)Xstream序列化Json的重命名　　

@XStreamAlias("人")
class Person
{
	@XStreamAlias("姓名")
	private String name;
	@XStreamAlias("年龄")
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class Test
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream(new JettisonMappedXmlDriver());//设置Json解析器
		xstream.autodetectAnnotations(true);
		//Json序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
		//Json反序列化
		bean=(Person)xstream.fromXML(xml);
		System.out.println(bean);
	}
}
    程序运行结果：
{"人":{"姓名":"张三","年龄":19}}
Person [name=张三, age=19]

注意：Xstream序列化Json的重命名的方式与其序列化成XML的方式一样！

(2)去掉序列化Json的根节点　　

class Person
{
	private String name;
	private int age;
	public Person(String name, int age)
	{
		this.name = name;
		this.age = age;
	}
	@Override
	public String toString()
	{
		return "Person [name=" + name + ", age=" + age + "]";
	}
}
public class Test00
{
	public static void main(String[] args)
	{
		Person bean=new Person("张三",19);
		XStream xstream = new XStream(new JsonHierarchicalStreamDriver()
		{
			public HierarchicalStreamWriter createWriter(Writer writer)
			{
				return new JsonWriter(writer, JsonWriter.DROP_ROOT_MODE);
			}
		});
		//Json序列化
		String xml = xstream.toXML(bean);
		System.out.println(xml);
	}
}
    程序运行结果：
{ "name": "张三", "age": 19 }

注意：去掉根节点后的Json串是不能反序列化的，因为XStream 不知道它的类型。

(3)Json的解析器区别

前面两个例子使用了不同的Json解析器，这里说明他们的不同之处：

JettisonMappedXmlDriver：是支持序列化和反序列化Json的。
JsonHierarchicalStreamDriver：只支持序列化，不支持反序列化。

　　本文来源:　　http://www.cnblogs.com/LiZhiW/p/4313493.html

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