用Castor 处理XML文档

——Castor可以完成Java和XML的相互转换这里将介绍Castor来完成Java对象到xml的相互转换。

它是怎么样转换的？和前面不同的是castor可以用一个mapping.xml文件来描述转换后的Java对象的xml基本形态，类似于xStream的annotation，这点还是非常不错的。

下面我们就来看看Castor是怎么样完成Java 对象到XML之间的相互转换吧。

一、准备工作1、官方资源本示例会运用到如下依赖包（jar包）：2、程序测试运行代码package com.hoo.test;import java.io.IOException;import java.io.StringReader;import java.io.StringWriter;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.exolab.castor.mapping.Mapping;import org.exolab.castor.mapping.MappingException;import org.exolab.castor.xml.MarshalException;import org.exolab.castor.xml.Marshaller;import org.exolab.castor.xml.Unmarshaller;import org.exolab.castor.xml.ValidationException;import org.junit.After;import org.junit.Before;import org.junit.Test;import com.hoo.entity.Account;import com.hoo.entity.AccountArray;import com.hoo.entity.Birthday;import com.hoo.entity.ListBean;import com.hoo.entity.MapBean;/*** <b>function:</b>Castor完成Java对象到XML的相互转换* 依赖jar: castor-1.3.jar* castor-1.3-core.jar* junit-4.8.2.jar* log4j-1.2.16.jar* commons-logging.jar* @author hoojo* @createDate 2011-4-21 下午07:57:26* @file CastorTest.java* @package com.hoo.test* @project WebHttpUtils* @blog /IBM_hoojo* @email hoojo_@* @version 1.0*/public class CastorTest {private Account bean = null;private Mapping mapping = new Mapping();private StringWriter writer = null;private StringReader reader = null;@Beforepublic void init() {bean = new Account();bean.setAddress("北京");bean.setEmail("email");bean.setId(1);bean.setName("jack");Birthday day = new Birthday();day.setBirthday("2010-11-22");bean.setBirthday(day);try {/*** 加载mapping.xml，此文件是对需要转换的Java对象的配置描述， * 即：转换后的Java对象的xml内容的转换规则*/mapping.loadMapping(System.getProperty("user.dir") +"\\src\\mapping.xml");} catch (IOException e) {e.printStackTrace();} catch (MappingException e) {e.printStackTrace();}}@Afterpublic void destory() {bean = null;mapping = null;try {if (writer != null) {writer.flush();writer.close();}if (reader != null) {reader.close();}} catch (IOException e) {e.printStackTrace();}System.gc();}public void fail(Object o) {System.out.println(o);}public void failRed(Object o) {System.err.println(o);}}Mapping对象可以完成Java对象到XML的编组和解组，它需要先设定一个mapping.xml，通过xml对JavaObject的描述。

来完成JavaObject的编组、解组工作。

3、看看即将被转换的JavaEntity代码Accountpackage com.hoo.entity;public class Account {private int id;private String name;private String email;private String address;private Birthday birthday;//setter、getter@Overridepublic String toString() {return this.id + "#" + + "#" + this.email + "#" + this.address + "#" + this.birthday;}}Birthdaypackage com.hoo.entity;public class Birthday {private String birthday;public Birthday(String birthday) {super();this.birthday = birthday;}//getter、setterpublic Birthday() {}@Overridepublic String toString() {return this.birthday;}}AccountArraypackage com.hoo.entity;public class AccountArray {private Account[] accounts;private int size;public int getSize() {size = accounts.length;return size;}public void setSize(int size) {this.size = size;}public Account[] getAccounts() {return accounts;}public void setAccounts(Account[] accounts) {this.accounts = accounts;}}ListBeanpackage com.hoo.entity;import java.util.List;public class ListBean {private String name;private List list;//setter、getter}MapBeanpackage com.hoo.entity;import java.util.Map;public class MapBean {private Map<String, Object> map;public Map<String, Object> getMap() {return map;}public void setMap(Map<String, Object> map) { this.map = map;}}二、编组JavaObject到XML1、将JavaBean编组，转换成XML/*** <b>function:</b>将Javabean编组，转换成XML* @author hoojo* @createDate 2011-4-22 下午12:08:48*/@Testpublic void writeBean2XML() {writer = new StringWriter();try {//编组Marshaller.marshal(bean, writer);fail(writer);} catch (MarshalException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}代码很简单，通过Marshaller的marshal方法来完成Java对象到XML的编组（序列化、转换）工作。

运行后的结果如下：<?xml version="1.0" encoding="UTF-8"?><account id="1"><address>北京</address><email>email</email><name>jack</name><birthday><birthday>2010-11-22</birthday></birthday></account>2、将List集合转换成XML/*** <b>function:</b>将List转换成xml* @author hoojo* @createDate 2011-4-22 下午12:11:00*/@Testpublic void writeList2XML() {writer = new StringWriter();List<Account> list = new ArrayList<Account>();list.add(bean);bean = new Account();bean.setName("tom");bean.setId(223);list.add(bean);try {Marshaller.marshal(list, writer);fail(writer);} catch (MarshalException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}运行后，结果如下：<?xml version="1.0" encoding="UTF-8"?><array-list><account xmlns:xsi="/2001/XMLSchema-instance"xmlns:java="" id="1" xsi:type="java:com.hoo.entity.Account"><address>北京</address><email>email</email><name>jack</name><birthday><birthday>2010-11-22</birt hday></birthday></account><account xmlns:xsi="/2001/XMLSchema-instance"xmlns:java="" id="223" xsi:type="java:com.hoo.entity.Account"> <name>tom</name></account></array-list>怎么样，List存放的是2个Account吧。