求大神路过，JAXB怎样处理动态集合啊?

2012-04-16 10:54:43 385 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

JAXB2 jaxb-api.jar jaxb-xjc.jar jaxb-impl.jar activation.jar 无需安装，解压后即可。jaxb-api.jar，jaxb-xjc.jar，jaxb-impl.jar，activation.jar等相关jar包在lib文件夹下。立即下载

就是当我用JAXB转xml字符串为java对象时，里面包含有集合对象。但是集合对象中的类型又不固定。

我想用java的多态来实现，但是好像JAXB并不能识别。

简单核心代码如下：



	import java.sql.ResultSet;

	import java.sql.SQLException;

	import java.util.ArrayList;

	import java.util.List;

	

	import org.springframework.jdbc.core.JdbcTemplate;

	import org.springframework.jdbc.core.RowMapper;

		

	import com.keer.common.domain.ListBean;

	import com.keer.common.domain.Person;

	

	public class Test{

		

		private JdbcTemplate jdbcTemplate;

		

		//这是Test类型

		public String getAc01All() {

			String sql ="select aac001,aac002,aac003 from ac01";

			List<Person> list = jdbcTemplate.query(sql, new RowMapper<Person>(){

				public Person mapRow(ResultSet rs, int rowNum) throws SQLException {

					Person p = new Person();

					p.setAac001(rs.getString("aac001"));

					p.setAac002(rs.getString("aac002"));

					p.setAac003(rs.getString("aac003"));

					return p;

				}

			});

			ListBean<Person> lb = new ListBean<Person>();

			

			String s =list2XML(lb.getClass(),list);	

			

			System.out.println(s);

			return s;

		}





		public String list2XML(Class<?> cla,List<?> list,Class<?> clas){

			StringWriter writer = new StringWriter();

			ListBean lb =null;

			try {

				

				Object o=cla.newInstance();

				if(o instanceof ListBean){

					lb = (ListBean)o;

					lb.setList(list);

				}

				JAXBContext context = null;

				if(null != clas){

					context = JAXBContext.newInstance(cla,clas);

				}else{

					context = JAXBContext.newInstance(cla);

				}

				

				marshallXmlType(lb, writer);

			} catch (Exception e) {

				e.printStackTrace();

			}

			  return writer.toString();

		}

		

		

		public static <T> void marshallXmlType(T value, Writer os) {  

			try {  

				Class<T> clzz = (Class<T>)value.getClass();  

				JAXBContext context = JAXBContext.newInstance(clzz);

				Marshaller m = context.createMarshaller();

				m.setProperty(Marshaller.JAXB_ENCODING, "UTF-8");

				m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);

				m.setProperty(Marshaller.JAXB_FRAGMENT, Boolean.FALSE);

				m.setAdapter(ListAdapter.class,new ListAdapter<Person>());

				QName name = new QName(clzz.getSimpleName());

				JAXBElement<T> element = new JAXBElement<T>(name, clzz, value);  

				m.marshal(element, os);  

			} catch (JAXBException e) {  

				e.printStackTrace();  

			}

		}

		

		public static void main(String[] args) {

			System.out.println(new PersonInfo().getAc01All());

		}

	}



	//List模型类

	

	import java.util.List;



	import javax.xml.bind.annotation.XmlAttribute;

	import javax.xml.bind.annotation.XmlRootElement;

	import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;



	@XmlRootElement(name = "ListBean")

	public class ListBean<T> {

		

		private String name;

		private List<T> list;

		

		@XmlJavaTypeAdapter(ListAdapter.class)

		public List<T> getList() {

			return  list;

		}

	 

		public void setList(List<T> list) {

			this.list = list;

		}

		

		@XmlAttribute

		public String getName() {

			return name;

		}

	 

		public void setName(String name) {

			this.name = name;

		}

	}



	//模型类



	import javax.xml.bind.annotation.XmlAccessType;

	import javax.xml.bind.annotation.XmlAccessorType;

	import javax.xml.bind.annotation.XmlElement;

	import javax.xml.bind.annotation.XmlRootElement;

	import javax.xml.bind.annotation.XmlType;

	

	@XmlRootElement(name = "Person")

	public class Person extends Domain {



		@XmlElement(required = true)

		protected String aac001;

		@XmlElement(required = true)

		protected String aac002;

		@XmlElement(required = true)

		protected String aac003;

	}

	

	//xml2集合转换类

	import java.util.ArrayList;

	import java.util.List;



	import javax.xml.bind.annotation.adapters.XmlAdapter;

	

	public class ListAdapter<T extends Domain> extends XmlAdapter<Domain [], List<Domain>> {



		public T [] marshal(List<Domain> domains) throws Exception {

			Domain [] dos = new Domain[domains.size()];

			int i = 0;

			for (Domain domain : domains) {

				dos[i++] = domain;

				System.out.println(domain.getClass().getSimpleName());

			}

			return (T[]) dos;

		}



		public List<Domain> unmarshal(Domain [] paramValueType) throws Exception {

			List<Domain> list = new ArrayList<Domain>();

			for (Domain domain : list) {

				list.add(domain);

			}

			return list;

		}

	}

	

	//抽象模型类

	

	import java.io.Serializable;



	import javax.xml.bind.annotation.XmlRootElement;

	

	@XmlRootElement(name = "Domain")

	public class Domain implements Serializable {

		private static final long serialVersionUID = -3851152784887793734L;

	}

期望输出的xml格式内容为：



	<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

	<ListBean>

		<Domain>

			<aac001>3001415720</aac001>

			<aac002>542336197608166802</aac002>

			<aac003>巴桑</aac003>

		</Domain>

		<Domain>

			<aac001>3001415721</aac001>

			<aac002>542336196407126826</aac002>

			<aac003>罗布卓玛</aac003>

		</Domain>

		<Domain>

			<aac001>3001415722</aac001>

			<aac002>542336196507030020</aac002>

			<aac003>普珍</aac003>

		</Domain>

	</ListBean>

但是现在代码的输出是这样：



	<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

	<ListBean>

		<list>

			<item/>

			<item/>

			<item/>

		</list>

	</ListBean>

...全文

CXF-JAXB包的处理问题处理cxf版本和jaxb包中冲突问题,解决webservice中遇到的版本问题立即下载

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「已注销」 2012-04-17

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谢谢你啦 cseu 。问题解决了，原来是我的Person对象里面有多余的注解，而且转换方式也不一样。现在好了。真心感谢你！

cseu 2012-04-16

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基于你的代码



import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

import java.util.List;



@XmlRootElement(name = "ListBean")

public class ListBean<T> {



    private String name;

    private List<T> list;



    @XmlElement(name = "Domain")

    public List<T> getList() {

        return list;

    }



    public void setList(List<T> list) {

        this.list = list;

    }



    @XmlAttribute

    public String getName() {

        return name;

    }



    public void setName(String name) {

        this.name = name;

    }

}



import javax.xml.bind.JAXBContext;

import javax.xml.bind.JAXBException;

import javax.xml.bind.Marshaller;

import java.io.ByteArrayOutputStream;

import java.util.ArrayList;

import java.util.List;



public class Test {

    public static void main(String[] args) {

        Person person = new Person();

        person.aac001="aac001";

        person.aac002="aac002";

        person.aac003="aac003";



        List<Person> personList = new ArrayList<Person>();

        personList.add(person);



        ListBean<Person> listBean = new ListBean<Person>();

        listBean.setList(personList);



        try {

            JAXBContext context = JAXBContext.newInstance(ListBean.class, Person.class);

            Marshaller m = context.createMarshaller();

            m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);



            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

            m.marshal(listBean,outputStream);

            System.out.println(outputStream);

        } catch (JAXBException e) {

            e.printStackTrace();

        }

    }

}

其他Domain，Person类一样
我这里跑出来结果是



<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<ListBean>

    <Domain xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="person">

        <aac001>aac001</aac001>

        <aac002>aac002</aac002>

        <aac003>aac003</aac003>

    </Domain>

</ListBean>

「已注销」 2012-04-16

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大神啊我照你说的那样做了，但是要报错：



[javax.xml.bind.JAXBException: class com.keer.common.domain.Person nor any of its super class is known to this context.]

你能不能写一个小小的demo啊，小demo就行了，谢谢

cseu 2012-04-16

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泛型类型是可以识别的
要达到你的效果，可以这样改
in ListBean



    @XmlElement(name = "Domain")

    public List<T> getList() {

        return  list;

    }

获取JAXBContext时，



JAXBContext context = JAXBContext.newInstance(ListBean.class,Person.class);

其他不必要的代码都可以删除

求大神路过，JAXB怎样处理动态集合啊?

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