在了解jaxp中的sax和dom解析模型之后，可以尝试用第三方的jar包来完成xml的解析

下面展示了dom4j的学习的入门文档
参考文档：https://github.com/dom4j/dom4j/wiki/Quick-Start-Guide

可以先参考文档的内容，了解一下dom4j的简单用法，下面我自己写了个入门的程序，发现dom4j的api使用比原生的java的api使用简单很多

1.dom4j实例演示

目标：完成一个xml文件到javabean的转换，需要从xml文件解析出内容，然后封装一个java bean对象，然后输出

• maven的jar依赖

<dependency>
      <groupId>org.dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>2.1.0</version>
    </dependency>

• beans.xml文件

<beans>
    <bean id="bean1" class ="com.java.jaxp.dom">
          <property name="username">sunkang</property>
    </bean>
    <bean id="bean2" class ="com.java.jaxp.dom">
        <property name="name">sunkang</property>
        <property name="username">sunkang</property>
    </bean>

</beans>

• java beans的类

/**
 * @Project: jdk
 * @description:  beans对象
 * @author: sunkang
 * @create: 2018-10-19 09:21
 * @ModificationHistory who      when       What
 **/
public class Beans {
    public List<Bean> bean;
    @Override
    public String toString() {
        return "Beans{" +
                "bean=" + bean +
                '}';
    }
}
class Bean{
    public List<Property> properties;

    public  String id;

    public  String clazz;

    @Override
    public String toString() {
        return "Bean{" +
                "properties=" + properties +
                ", id='" + id + '\'' +
                ", clazz='" + clazz + '\'' +
                '}';
    }
}

 class Property{
    public String name ;
    public  String value;
    @Override
    public String toString() {
        return "Property{" +
                "name='" + name + '\'' +
                ", value='" + value + '\'' +
                '}';
    }
}

• dom4j解析程序

/**
 * @Project: jdk
 * @description: dom4j解析
 * @author: sunkang
 * @create: 2018-10-18 23:28
 * @ModificationHistory who      when       What
 **/
public class Dom4jParseXml {

    public static void main(String[] args) throws DocumentException {
        SAXReader saxReader = new SAXReader();

        String fileUrl = "D:\\Eclipse2018Data\\personProject\\jdk\\java-jaxp\\src\\main\\java\\com\\java\\jaxp\\dom4j\\Beans.xml";

        Document document =saxReader.read(fileUrl);

       Element root =  document.getRootElement();

       StringBuffer sbf = new StringBuffer();
       Beans beans = new Beans();
        beans.bean = new ArrayList<Bean>();
        //利用迭代器查找beans元素下的bean的元素
       for(Iterator i = root.elementIterator("bean");i.hasNext();){
           Bean bean = new Bean();
           Element  beanElement= (Element) i.next();
           String id  = beanElement.attributeValue("id");
           String clazz  = beanElement.attributeValue("class");
           bean.id= id;
           bean.clazz=clazz;
           bean.properties = new ArrayList<Property>();
           for(Iterator j = beanElement.elementIterator("property");j.hasNext();){
               Property property = new Property();
               Element  propertyElement= (Element) j.next();
               //获取property元素的属性name的值
               property.name=propertyElement.attributeValue("name");
               property.value = propertyElement.getText();
               //添加property实体
               bean.properties.add(property);
           }
           //添加bean实体
           beans.bean.add(bean);
       }

        System.out.println(beans);
    }
}