JAXB annotations for Parsing XML

最新推荐文章于 2021-02-12 17:17:48 发布

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本文介绍了一种利用Java架构进行XML绑定(JAXB)来解析XML文件的方法。通过定义Java类映射XML结构，实现了XML数据到Java对象的转换。案例展示了如何针对具体的XML文档设计对应的Java类，并通过JAXB工具类完成读取。

JAXB annotations for Parsing XML

The document of annotations is :
http://www.caucho.com/resin-3.1/doc/jaxb-annotations.xtp

my test XML file content is:
<?xml version="1.0" encoding="UTF-8"?>
<widget vendorId="131" version="1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<component sequence="0">
<name><![CDATA[Promo1]]></name>
<images>
<imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo1.png]]></imageURL>
</images>
<type>sku</type>
<content><![CDATA[1000080]]></content>
</component>
<component sequence="1">
<name><![CDATA[Promo6]]></name>
<images>
<imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo5.png]]></imageURL>
</images>
<type>category</type>

<content><![CDATA[633329]]>
</content>
</component>
<component sequence="2">
<name><![CDATA[Promo7]]></name>
<images>
<imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo5.png]]></imageURL>
</images>
<type>static</type>
<content>This is a Test.</content>
</component>
<component sequence="3">
<name><![CDATA[Promo8]]></name>
<images>
<imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo5.png]]></imageURL>
</images>
<type>url</type>
<content>http://www.google.com</content>
</component>
<component sequence="4">
<name><![CDATA[Promo9]]></name>
<images>
<imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo5.png]]></imageURL>
</images>
<type>search</type>
<content><![CDATA[1000080]]></content>
</component>
</widget>

According to the XML, my java objects are:
BannerWidget
BannerComponent
BannerImageCollection
BannerImage

BannerWidget.java is :

package com.xxx.bean.banner;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "widget")
public class BannerWidget
{
@XmlAttribute(name = "vendorId")
private String vendorId;
@XmlElement(name = "component")
private List<BannerComponent> components;
... snip getter and setter
}

@XmlRootElement is for root xml field
@XmlAttribute is for the attribute in the field, eg sequence in <component sequence="0">
@XmlElement is for the value part of the field,
eg <name> in <component sequence="0"><name><![CDATA[Promo1]]></name></component>

BannerComponent.java:
package com.xxxx.bean.banner;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
@XmlAccessorType(XmlAccessType.FIELD)
public class BannerComponent
{
@XmlAttribute(name = "sequence")
private int sequence;
@XmlElement(name = "name")
private String name;
@XmlElement(name = "images")
private BannerImageCollection images;
@XmlElement(name = "type")
private String type;
@XmlElement(name = "content")
private String content;
...snip getter and setter
}

BannerImageCollection.java:
package com.xxxx.bean.banner;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "images")
public class BannerImageCollection
{
@XmlElement(name = "imageURL")
private List<BannerImage> images;
...snip getter and setter...
}

BannerImage.java:
package com.xxxx.bean.banner;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlValue;
@XmlAccessorType(XmlAccessType.FIELD)
public class BannerImage
{
@XmlAttribute(name = "size")
private String size;
@XmlValue
private String imageURL;
...snip getter and setter...
}

@XmlValue is for all the part of property,
eg url part in <imageURL size="large"><![CDATA[http://www.sanrio.com/deliverables/iphone/promo/promo5.png]]></imageURL>

My testcase class XMLUtil.java is :
package com.xxxx.utils;

import java.io.FileNotFoundException;
import java.io.FileReader;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;

import com.xxxx.bean.banner.BannerWidget;

public class XmlUtil
{

/**
* Comment for main
*
* @param args
* Created by hua.luo.
*/
public static void main(String[] args)
{
JAXBContext jaxbContext = null;
BannerWidget bannerWidget = null;
FileReader fileReader = null;
try
{
fileReader = new FileReader("d://test//promotion.xml");

jaxbContext = JAXBContext.newInstance(BannerWidget.class);
bannerWidget = (BannerWidget) jaxbContext.createUnmarshaller().unmarshal(fileReader);
System.out.println(bannerWidget);
}
catch (JAXBException e)
{
e.printStackTrace();
}
catch (FileNotFoundException e)
{
e.printStackTrace();
}

}

}