场景

解析的一段 xml 报文信息：

<xml>
    <ToUserName><![CDATA[xxx]]></ToUserName>
    <FromUserName><![CDATA[xxx]]></FromUserName>
    <CreateTime>1675747313</CreateTime>
    <MsgType><![CDATA[event]]></MsgType>
    <Event><![CDATA[unsubscribe]]></Event>
    <EventKey><![CDATA[]]></EventKey>
</xml>

下面介绍几种常见的方式。

V1-dom4j

maven 引入

<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
</dependency>

实现

package com.github.houbb.xml.learn;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import java.util.*;

public class Dmo4jTest {

    public static void main(String[] args) {
        String returnMsg = "<xml><ToUserName><![CDATA[yyyy]]></ToUserName>\n" +
                "<FromUserName><![CDATA[xxxx]]></FromUserName>\n" +
                "<CreateTime>1675747313</CreateTime>\n" +
                "<MsgType><![CDATA[event]]></MsgType>\n" +
                "<Event><![CDATA[unsubscribe]]></Event>\n" +
                "<EventKey><![CDATA[]]></EventKey>\n" +
                "</xml>";

        try {
            Document doc = DocumentHelper.parseText(returnMsg);

            // 指向根节点
            Element root = doc.getRootElement();

            Iterator it = root.elementIterator();
            while (it.hasNext()) {
                // 一个Item节点
                Element element = (Element) it.next();
                System.out.println(element.getName() + " : " + element.getTextTrim());
            }

        } catch (DocumentException e) {
            e.printStackTrace();
        }

    }

}

输出日志：

ToUserName : yyyy
FromUserName : xxxx
CreateTime : 1675747313
MsgType : event
Event : unsubscribe
EventKey :

当然，这样转为 pojo 还需要额外的处理。

针对这一点，有一些工具已经非常成功。

V2-使用 xstream

maven 引入

<dependency>
    <groupId>com.thoughtworks.xstream</groupId>
    <artifactId>xstream</artifactId>
    <version>1.4.9</version>
</dependency>

java 实现

对应的 XstramWxEventMessage 对象定义如下：

package com.github.houbb.xml.learn.dto;

import com.thoughtworks.xstream.annotations.XStreamAlias;

import java.io.Serializable;

@XStreamAlias("xml")
public class XstramWxEventMessage implements Serializable {

    @XStreamAlias("ToUserName")
    private String toUserName;

    @XStreamAlias("FromUserName")
    private String fromUserName;

    @XStreamAlias("CreateTime")
    private String createTime;

    @XStreamAlias("MsgType")
    private String msgType;

    @XStreamAlias("Event")
    private String event;

    @XStreamAlias("EventKey")
    private String eventKey;

    // getter&setter&toString

}

我们可以通过 @XStreamAlias 指定字段和类的别名。

package com.github.houbb.xml.learn;

import com.github.houbb.xml.learn.dto.XstramWxEventMessage;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.xml.DomDriver;

public class XstramTest {

    public static void main(String[] args) {
        // 这是会报错，感觉场景不是很适合
        XStream xstream = new XStream(new DomDriver());
        xstream.processAnnotations(XstramWxEventMessage.class);

        XstramWxEventMessage message = new XstramWxEventMessage();
        message.setFromUserName("ffff");
        message.setToUserName("Xxxx");

        String xml = xstream.toXML(message);
        System.out.println(xml);


        String returnMsg = "<xml><ToUserName><![CDATA[yyyy]]></ToUserName>\n" +
                "<FromUserName><![CDATA[xxxx]]></FromUserName>\n" +
                "<CreateTime>1675747313</CreateTime>\n" +
                "<MsgType><![CDATA[event]]></MsgType>\n" +
                "<Event><![CDATA[unsubscribe]]></Event>\n" +
                "<EventKey><![CDATA[]]></EventKey>\n" +
                "</xml>";

        XstramWxEventMessage fromMessage = (XstramWxEventMessage) xstream.fromXML(returnMsg);
        System.out.println(fromMessage);
    }

}

输出日志：

<xml>
  <ToUserName>Xxxx</ToUserName>
  <FromUserName>ffff</FromUserName>
</xml>

WxEventMessage{toUserName='yyyy', fromUserName='xxxx', createTime='1675747313', msgType='event', event='unsubscribe', eventKey=''}

这样使用起来比较方便，不过对于 xml 这个必须限定指定别称，感觉也挺别扭的。

V3-jaskson

maven

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
    <version>2.9.7</version>
</dependency>

java 实现

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;

import java.io.Serializable;

@JsonIgnoreProperties(ignoreUnknown = true)
public class JacksonWxEventMessage implements Serializable {

    @JacksonXmlProperty(localName = "ToUserName")
    private String toUserName;

    @JacksonXmlProperty(localName = "FromUserName")
    private String fromUserName;

    @JacksonXmlProperty(localName = "CreateTime")
    private String createTime;

    @JacksonXmlProperty(localName = "MsgType")
    private String msgType;

    @JacksonXmlProperty(localName = "Event")
    private String event;

    @JacksonXmlProperty(localName = "EventKey")
    private String eventKey;

    // getter&setter&toString

}

测试代码

import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.github.houbb.xml.learn.dto.JacksonWxEventMessage;

public class JasksonTest {

    public static void main(String[] args) {
        String returnMsg = "<xml><ToUserName><![CDATA[yyyy]]></ToUserName>\n" +
                "<FromUserName><![CDATA[xxxx]]></FromUserName>\n" +
                "<CreateTime>1675747313</CreateTime>\n" +
                "<MsgType><![CDATA[event]]></MsgType>\n" +
                "<Event><![CDATA[unsubscribe]]></Event>\n" +
                "<EventKey><![CDATA[]]></EventKey>\n" +
                "</xml>";

        try {
            XmlMapper xmlMapper = new XmlMapper();

            JacksonWxEventMessage jacksonWxEventMessage = xmlMapper.readValue(returnMsg, JacksonWxEventMessage.class);

            System.out.println(jacksonWxEventMessage);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

总结

实现的方式有多种，选择合适自己业务的即可。