最近遇到一个问题，需要从一个url获取xml文档并解析，google了很多方法，大多数都
是获取到XML然后循环遍历拿到数据，但是感觉很麻烦，并且感觉当数据量比较大的时候效率也不怎么
高，后面研究了下，发现JAXB这个好东西，可以实现JavaBean和XML节点元素的互相转换，故此总结一
下：
1、相关链接
- Maven Plugins ：http://mvnrepository.com/
2、准备工作
需要安装JAXB和dom4j，如果用的Maven，可以访问上面的url，并搜索JAXB和dom4j，选择需要的版本
，复制下面的代码配置到自己的项目中：
3、获取并解析
先看一下返回的XML格式
解析
public static void main(String[] args) {
//获取XML
SAXReader reader = new SAXReader();
org.dom4j.Document document = reader.read(new URL("http://api.************************ */v2.0/hotel/geo_cn.xml")));
String documentStr = document.asXML();
//将xml字符串转换为java对象
JaxbUtil resultBinder = new JaxbUtil(HotelGeos.class, JaxbUtil.CollectionWrapper.class);
HotelGeos hotelObj = resultBinder.fromXml(documentStr);
//将java对象转换为XML字符串
HotelGeos hotelGeos=new HotelGeos();
List hotelGeoList=new ArrayList<>();
HotelGeo hotelGeo =new HotelGeo();
hotelGeo.setCityCode("0101");
hotelGeo.setCityName("北京市");
hotelGeo.setCountry("中国");
hotelGeo.setProvinceId("0100");
hotelGeo.setProvinceName("北京市");
//其他层级的这里就不一一赋值了
hotelGeoList.add(hotelGeo);
hotelGeos.setHotelGeoList(hotelGeoList);
JaxbUtil requestBinder = new JaxbUtil(HotelGeos.class, CollectionWrapper.class);
String retXml = requestBinder.toXml(hotelGeos, "utf-8");
System.out.println("xml:"+retXml);
}
相关类之HotelGeos
package com .*****.geoData.items;
import lombok.Data;
import javax.xml.bind.annotation .*;
import java.util.List;
/**
* Created by IntelliJ IDEA.
* User: Steven
* Date: 2019/12/05
* Time: 13:36
*/
@Data
@XmlRootElement(name = "HotelGeos")
public class HotelGeos {
@XmlElementWrapper(name = "HotelGeoList")
@XmlElement(name = "HotelGeo")
private List HotelGeoList;
}
HotelGeo
package com.***.geoData.items;
import lombok.Data;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import java.io.Serializable;
import java.util.List;
/**
* Created by IntelliJ IDEA.
* User: Steven
* Date: 2019/12/06
* Time: 13:38
*/
@Data
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class HotelGeo implements Serializable {
@XmlAttribute(name = "CityCode")
private String CityCode;
@XmlAttribute(name = "CityName")
private String CityName;
@XmlAttribute(name = "Country")
private String Country;
@XmlAttribute(name = "ProvinceId")
private String ProvinceId;
@XmlAttribute(name = "ProvinceName")
private String ProvinceName;
@XmlElementWrapper(name = "CommericalLocations")
@XmlElement(name = "Location") //这里需要格外注意，层级很容易写错
private List CommericalLocations;
@XmlElementWrapper(name = "Districts")
@XmlElement(name = "Location")
private List Districts;
@XmlElementWrapper(name = "LandmarkLocations")
@XmlElement(name = "Location")
private List LandmarkLocations;
}
Location
package com.*****.geoData.items;
import lombok.Data;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import javax.xml.bind.annotation.XmlAttribute;
import java.io.Serializable;
/**
* Created by IntelliJ IDEA.
* User: Steven
* Date: 2019/12/06
* Time: 13:53
*/
@Data
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class Location implements Serializable {
@XmlAttribute(name = "Id")
private String Id;
@XmlAttribute(name = "Name")
private String Name;
}
JaxbUtil工具类
package com.*****.utils;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Collection;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.namespace.QName;
import org.apache.commons.lang.StringUtils;
/**
* 使用Jaxb2.0实现XML<->Java Object的Binder.
*
* 特别支持Root对象是List的情形.
*
* @author
*/public class JaxbUtil {
// 多线程安全的Context.
private JAXBContext jaxbContext;
/**
* @param types
* 所有需要序列化的Root对象的类型.
*/
public JaxbUtil(Class... types) {
try {
jaxbContext = JAXBContext.newInstance(types);
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* Java Object->Xml.
*/
public String toXml(Object root, String encoding) {
try {
StringWriter writer = new StringWriter();
createMarshaller(encoding).marshal(root, writer);
return writer.toString();
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* Java Object->Xml, 特别支持对Root Element是Collection的情形.
*/
@SuppressWarnings("unchecked")
public String toXml(Collection root, String rootName, String encoding) {
try {
CollectionWrapper wrapper = new CollectionWrapper();
wrapper.collection = root;
JAXBElement wrapperElement = new JAXBElement(
new QName(rootName), CollectionWrapper.class, wrapper);
StringWriter writer = new StringWriter();
createMarshaller(encoding).marshal(wrapperElement, writer);
return writer.toString();
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}/**
* Xml->Java Object.
*/
@SuppressWarnings("unchecked")
public T fromXml(String xml) {
try {
StringReader reader = new StringReader(xml);
return (T) createUnmarshaller().unmarshal(reader);
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* Xml->Java Object, 支持大小写敏感或不敏感.
*/
@SuppressWarnings("unchecked")
public T fromXml(String xml, boolean caseSensitive) {
try {
String fromXml = xml;
if (!caseSensitive)
fromXml = xml.toLowerCase();
StringReader reader = new StringReader(fromXml);
return (T) createUnmarshaller().unmarshal(reader);
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* 创建Marshaller, 设定encoding(可为Null).
*/
public Marshaller createMarshaller(String encoding) {
try {
Marshaller marshaller = jaxbContext.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
if (StringUtils.isNotBlank(encoding)) {
marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
}
return marshaller;
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* 创建UnMarshaller
*/
public Unmarshaller createUnmarshaller() {
try {
return jaxbContext.createUnmarshaller();
} catch (JAXBException e) {
throw new RuntimeException(e);
}
}
/**
* 封装Root Element 是 Collection的情况.
*/
public static class CollectionWrapper {
@SuppressWarnings("unchecked")
@XmlAnyElement
protected Collection collection;
}
}