Xml字符串和Java对象转换利器——XStream

Maven配置：

	com.thoughtworks.xstream
	xstream
	1.4.7

实体类见博客《Json字符串和Java对象转换利器——Jackson》。所有的实体类除了包名不同，成员都一样。

工具类XStreamUtil：

package org.xstream;

import java.io.Writer;
import java.util.List;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
import com.thoughtworks.xstream.io.xml.XppDriver;

public class XStreamUtil {
	
	/**
	 * Java对象转Xml字符串（序列化）
	 * @param object
	 * @return
	 */
	public String bean2Xml(Object object){
		XStream stream = new XStream(new XppDriver() {
			public HierarchicalStreamWriter createWriter(Writer out) {
				return new PrettyPrintWriter(out) {

					public void startNode(String name) {
						// 去掉包名
						if (name.indexOf(".") > -1) {
							name = name.substring(name.lastIndexOf(".") + 1);
						}
						super.startNode(name);
					};
				};
			}
		});
		return stream.toXML(object);
	}
	
	/**
	 * Xml字符串转Java对象（反序列化）
	 * @param xml
	 * @param rootName 根元素名称
	 * @param rootType 根元素对应的Java类型
	 * @param collectionTypes 集合类型
	 * @return
	 */
	public Object xml2Bean(String xml, String rootName, Class rootType, 
			List> collectionTypes){
		XStream stream = new XStream();
		stream.alias(rootName, rootType);
		for (Class clazz : collectionTypes) {
			stream.alias(clazz.getSimpleName(), clazz);
		}
		Object bean = stream.fromXML(xml);
		return bean;
	}
}

测试类XStreamUtilTest：

package org.xstream;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.xstream.po.GetOrdersResponse;
import org.xstream.po.Order;
import org.xstream.po.PaginationResult;
import org.xstream.po.order.CheckoutStatus;

public class XStreamUtilTest {
	
	XStreamUtil streamUtil;
	GetOrdersResponse ordersResponse;
	static String xmlStr;
	
	@Before
	public void before() {
		streamUtil = new XStreamUtil();
		
		ordersResponse = new GetOrdersResponse();
		ordersResponse.setTimestamp("2007-12-10T16:12:55.184Z");
		ordersResponse.setAck("Success");
		ordersResponse.setBuild("e539_core_Bundled_5642307_R1");
		ordersResponse.setVersion("539");
		List orders = new ArrayList();
		for (int i = 0; i < 3; i++) {
			Order order = new Order();
			order.setOrderID("OrderId_" + i);
			order.setBuyerUserID("BuyerUserId_" + i);
			
			CheckoutStatus checkoutStatus = new CheckoutStatus();
			checkoutStatus.setEBayPaymentStatus("EBayPaymentStatus_" + i);
			checkoutStatus.setLastModifiedTime("LastModifiedTime_" + i);
			checkoutStatus.setStatus("Status_" + i);
			order.setCheckoutStatus(checkoutStatus);
			
			orders.add(order);
		}
		ordersResponse.setOrderArray(orders);
		PaginationResult paginationResult = new PaginationResult();
		paginationResult.setTotalNumberOfEntries("10");
		paginationResult.setTotalNumberOfPages("5");
		ordersResponse.setPaginationResult(paginationResult);
	}
	
	@Test
	public void bean2Xml(){
		xmlStr = streamUtil.bean2Xml(ordersResponse);
		System.out.println("--------序列化---------");
		System.out.println(xmlStr);
	}
	
	@Test
	public void xml2Bean(){
		System.out.println("----------反序列化---------");
		System.out.println(streamUtil.xml2Bean(xmlStr, 
				GetOrdersResponse.class.getSimpleName(), GetOrdersResponse.class, 
				Arrays.asList(new Class[]{Order.class})));
	}
}

结果：

--------序列化---------

  2007-12-10T16:12:55.184Z
  Success
  539
  e539_core_Bundled_5642307_R1
  
    10
    5
  
  
    
      OrderId_0
      
        EBayPaymentStatus_0
        LastModifiedTime_0
        Status_0
      
      BuyerUserId_0
    
    
      OrderId_1
      
        EBayPaymentStatus_1
        LastModifiedTime_1
        Status_1
      
      BuyerUserId_1
    
    
      OrderId_2
      
        EBayPaymentStatus_2
        LastModifiedTime_2
        Status_2
      
      BuyerUserId_2
    
  

----------反序列化---------
GetOrdersResponse [ack=Success, build=e539_core_Bundled_5642307_R1, orderArray=[Order [buyerUserID=BuyerUserId_0, checkoutStatus=CheckoutStatus [eBayPaymentStatus=EBayPaymentStatus_0, lastModifiedTime=LastModifiedTime_0, status=Status_0], orderID=OrderId_0], Order [buyerUserID=BuyerUserId_1, checkoutStatus=CheckoutStatus [eBayPaymentStatus=EBayPaymentStatus_1, lastModifiedTime=LastModifiedTime_1, status=Status_1], orderID=OrderId_1], Order [buyerUserID=BuyerUserId_2, checkoutStatus=CheckoutStatus [eBayPaymentStatus=EBayPaymentStatus_2, lastModifiedTime=LastModifiedTime_2, status=Status_2], orderID=OrderId_2]], paginationResult=PaginationResult [totalNumberOfEntries=10, totalNumberOfPages=5], timestamp=2007-12-10T16:12:55.184Z, version=539]

需要注意的是，在反序列化时，如果XML元素冗余，则会抛出UnknownFieldException异常，此时可以设置忽略未知元素：

xstream.ignoreUnknownElements();

如果要将XML元素中的属性与Java对象的字段对应，该怎么办呢？例如有XML元素：

Java类：

class Order{
        private String orderID;
}

此时可以进行如下设置：

xstream.aliasAttribute(Order.class, "orderID", "id");