XStream 用法详解 java 类与 XML 互换

本例使用XStream生成一个xml文件，再发序列化xml文件内容。

XStream是一个简单的类库，可以序列化对象到xml，还可以将xml还原为对象。 
XStream官网：http://xstream.codehaus.org/ 
附件提供XStream和xpp3相关的jar下载： 
xstream-1.2.2.jar 
xpp3-1.1.3.3_min.jar 
为了使用XStream，需要对其初始化，初始化方法有两种： 

• XStream xstream = new XStream();   这种方式的初始化需要xpp3-[version].jar的支持。xpp是一个快速解析XML文件的解析器。
• XStream xstream = new XStream(new DomDriver()); XStream xStream = new XStream(new DomDriver("utf-8"))      这种方式不需要依赖XPP3.jar的支持,它是使用标准的JAXP DOM来解析它。

同时这里对mode参数做个简单的说明： 
在XStream序列化或反序列化对象时，它会创建两个类MarshallingContext和UnmarshallingContext，由它们来处理数据，以及委派合适的转换器。XStream提供了三对上下文的缺省实现，它们之间有着细微的差别。缺省值可以通过方法XStream.setMode()来改变，需要传递下面参数中的一个： 

• XStream.XPATH_RELATIVE_REFERENCES：(缺省)通过XPath引用来标识重复的引用,使用相对路径表示。
• XStream.XPATH_ABSOLUTE_REFERENCES：通过XPath引用来标识重复的引用,使用绝对路径表示。
• XStream.ID_REFERENCES：使用ID引用来标识重复的引用。在一些场合（手写XML时），将会更易于操作
• XStream.NO_REFERENCES：这种情况将失去对图形对象的支持，仅把对象看作为树型结构。重复的引用被视作两个不同的对象，循环引用会导致异常产生。相对于上面两种模式，这种模式速度会更快，占用内存会更

这个例子包含有3个简单的java类，其中两个是javabean，另外一个是逻辑处理类。

<span style="white-space: normal; background-color: #ffffff;">package com.xstream.entity</span>

import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
import com.thoughtworks.xstream.annotations.XStreamImplicit;

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

/**
 * User: Rojer
 * Date: 12-3-1
 * Time: 下午4:58
 * To change this template use File | Settings | File Templates.
 */
//设置Person类在xml中的别名
@XStreamAlias("person")
public class Person {
    //将name设置为XML person 元素的 attribute
    @XStreamAsAttribute()
    private String name;
    private int phoneNuber;
    //将此字段名在XML中去掉
    @XStreamImplicit()
    private List<Address> addresses = new ArrayList<Address>();

    public List<Address> getAddresses() {
        return addresses;
    }

    public void setAddresses(List<Address> addresses) {
        this.addresses = addresses;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPhoneNuber() {
        return phoneNuber;
    }

    public void setPhoneNuber(int phoneNuber) {
        this.phoneNuber = phoneNuber;
    }


}

   Adress

 

package com.xstream.entity;

import com.thoughtworks.xstream.annotations.XStreamAlias;

/**
 * User: Rojer
 * Date: 12-3-1
 * Time: 下午5:00
 * To change this template use File | Settings | File Templates.
 */
@XStreamAlias("address")
public class Address {
    private String street;
    private int houseNo;

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public int getHouseNo() {
        return houseNo;
    }

    public void setHouseNo(int houseNo) {
        this.houseNo = houseNo;
    }
}

 测试类

 

package com.xstream.test;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.io.xml.Dom4JDriver;
import com.thoughtworks.xstream.io.xml.DomDriver;
import com.thoughtworks.xstream.io.xml.StaxDriver;
import com.xstream.entity.Address;
import com.xstream.entity.Person;
import org.xmlpull.mxp1.MXParser;

import java.io.ObjectInputStream;
import java.io.StringReader;

/**
 * User: Rojer
 * Date: 12-3-1
 * Time: 下午4:48
 * To change this template use File | Settings | File Templates.
 */
public class TestStream {

    public static void main(String[] args) {
        String res=toXML();
        toEntity(res);
    }

    public static void toEntity(String inputXML){
        XStream xs = new XStream();
//        这句和@XStreamAlias("person")等效
//        xs.alias("person",Person.class);
//        xs.alias("address",Address.class);
        xs.setMode(XStream.NO_REFERENCES);
//      这句和@XStreamImplicit()等效
//        xs.addImplicitCollection(Person.class,"addresses");
//        这句和@XStreamAsAttribute()
//        xs.useAttributeFor(Person.class, "name");
        //注册使用了注解的VO
        xs.processAnnotations(new Class[]{Person.class,Address.class});
        Person person = (Person)xs.fromXML(inputXML);
        System.out.println(person.getAddresses().get(0).getHouseNo()+person.getName());



    }

    public static String toXML(){
        XStream xStream = new XStream();
        Person person = new Person();
        person.setName("rojer");
        person.setPhoneNuber(999);
        Address address1 = new Address();
        address1.setHouseNo(888);
        address1.setStreet("newyork");
        Address address2 = new Address();
        address2.setHouseNo(76767);
        address2.setStreet("toyo");
        person.getAddresses().add(address1);
        person.getAddresses().add(address2);
//        xStream.alias("person", Person.class);
//        xStream.alias("address",Address.class);
        xStream.setMode(XStream.NO_REFERENCES);
//        xStream.addImplicitCollection(Person.class, "addresses");
//        xStream.useAttributeFor(Person.class,"name");
        //注册使用了注解的VO
        xStream.processAnnotations(new Class[]{Person.class,Address.class});
        String xml = xStream.toXML(person);

        System.out.println(xml);
        return xml;
    }
}

 测试结果如下

 

 

<person name="rojer">
  <phoneNuber>999</phoneNuber>
  <address>
    <street>newyork</street>
    <houseNo>888</houseNo>
  </address>
  <address>
    <street>toyo</street>
    <houseNo>76767</houseNo>
  </address>
</person>
888rojer

 如果去掉Person类的@XStreamImplicit()注解，生成的XML如下

 

<person name="rojer">
  <phoneNuber>999</phoneNuber>
  <addresses>
    <address>
      <street>newyork</street>
      <houseNo>888</houseNo>
    </address>
    <address>
      <street>toyo</street>
      <houseNo>76767</houseNo>
    </address>
  </addresses>
</person>
888rojer

 其字段addresses 会被写入到XML中。

http://chen-rojer-gmail-com.iteye.com/blog/1435254/