xml解析之xstream

XStream是Java类库，用来将对象序列化成XML （JSON）或反序列化为对象。相对于jaxb来说要简单易用些，但是也会消耗更多的时间。

一、引入XStream的包

<dependency>
      <groupId>com.thoughtworks.xstream</groupId>
      <artifactId>xstream</artifactId>
      <version>1.4.11.1</version>
</dependency>

二、将xml转换为Java实体类对象

下面以微信公众号事件消息通知为例。xml内容如下：

<xml>
    <ToUserName><![CDATA[toUser]]></ToUserName>
    <FromUserName><![CDATA[FromUser]]></FromUserName>
    <CreateTime>123456789</CreateTime>
    <MsgType><![CDATA[event]]></MsgType>
    <Event><![CDATA[CLICK]]></Event>
    <EventKey><![CDATA[EVENTKEY]]></EventKey>
</xml>

创建实体类：ClickMenuEvent

import com.thoughtworks.xstream.annotations.XStreamAlias;
import lombok.Data;

import java.io.Serializable;

/**
 * <p> 点击菜单拉取消息时的事件推送 </p>
 */
@Data //这个是lombok的注解，加上后编译的class文件中会自动生成get set相关方法，记得安装lombok插件
@XStreamAlias("xml") //定义xml根节点
public class ClickMenuEvent implements Serializable {

    //消息类型，event
    @XStreamAlias("MsgType")//xml中的名称和实体类中名称进行映射
    private String msgType;

    //事件类型，CLICK
    @XStreamAlias("Event")
    private String event;

    //开发者 微信号
    @XStreamAlias("ToUserName")
    private String toUserName;

    //发送方帐号（一个OpenID）
    @XStreamAlias("FromUserName")
    private String fromUserName;

    //消息创建时间 （整型）
    @XStreamAlias("CreateTime")
    private String createTime;

    //事件KEY值，与自定义菜单接口中KEY值对应
    @XStreamAlias("eventKey")
    private String EventKey;
}

开始解析：

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.naming.NoNameCoder;
import com.thoughtworks.xstream.io.xml.XppDriver;

public class MyTest {

    public static void main(String[] args) {
        String xml = "<xml>" +
                "<ToUserName><![CDATA[toUser]]></ToUserName>" +
                "<FromUserName><![CDATA[FromUser]]></FromUserName>" +
                "<CreateTime>123456789</CreateTime>" +
                "<MsgType><![CDATA[event]]></MsgType>" +
                "<Event><![CDATA[CLICK]]></Event>" +
                "<EventKey><![CDATA[EVENTKEY]]></EventKey>" +
                "</xml>";
        
        XStream xStream = new XStream(new XppDriver(new NoNameCoder()));
        xStream.processAnnotations(ClickMenuEvent.class);
        //解决提示 Security framework of XStream not initialized, XStream is probably vulnerable.
        xStream.allowTypes(new Class[]{ClickMenuEvent.class});
        ClickMenuEvent pojo = (ClickMenuEvent) xStream.fromXML(xml);
        System.out.println(pojo.toString());
    }
    
}

三、将Java实体对象转xml

同样使用上面的实体对象ClickMenuEvent

public static void main(String[] args) {
    XStream xStream = new XStream(new XppDriver(new NoNameCoder()));
    xStream.processAnnotations(ClickMenuEvent.class);
    ClickMenuEvent pojo = new ClickMenuEvent();
    pojo.setCreateTime("9876543210");
    pojo.setEvent("CLICK");
    pojo.setEventKey("123456");
    pojo.setMsgType("event");
    pojo.setFromUserName("张三");
    pojo.setToUserName("李四");
    String xml = xStream.toXML(pojo);
    System.out.println(xml);
}

转换后的结果

<xml>
  <MsgType>event</MsgType>
  <Event>CLICK</Event>
  <ToUserName>李四</ToUserName>
  <FromUserName>张三</FromUserName>
  <CreateTime>9876543210</CreateTime>
  <eventKey>123456</eventKey>
</xml>