XStream序列化对象，java.util.Map自定义Converter

如果你不知道XStream是什么东东，请看我以前的一篇文章：

http://fuliang.iteye.com/blog/379429

 

今天用XStream序列化对象，其中有Map类型的字段，结果不让人满意：

 <ExtractResult>
  <dataRecords>
    <DataRecord>
      <properties>
        <property>
          <string>region</string>
          <string>非洲中东</string>
        </property>
        <property>
          <string>routeReference</string>
          <string>首都机场集合，搭乘土耳其航空直飞伊斯坦布尔，夜宿机上。</string>
        </property>
        <property>
          <string>routeDays</string>
          <string>10</string>
        </property>
        <property>
          <string>price</string>
          <string>￥13500起</string>
        </property>
        <property>
          <string>subject</string>
          <string>常规</string>
        </property>
        <property>
          <string>dayOfBookingExpired</string>
          <string>2010-02-01</string>
        </property>
        <property>
          <string>departure</string>
          <string>北京</string>
        </property>
        <property>
          <string>dayOfDeparture</string>
          <string>2010-02-10</string>
        </property>
        <property>
          <string>title</string>
          <string>[团队游]埃及土耳其10日千年文明之旅(春节)</string>
        </property>
      </properties>
    </DataRecord>
  </dataRecords>
</ExtractResult>

其中的key和value被序列化成：

 

<string>region</string>
<string>非洲中东</string>

我比较想要的结果是

 

<property key="region" value="非洲中东"/>

查看了XStream的文档，可以通过自定义Converter来转换，经过尝试，只需要很简单的步骤就可以完成：

 

import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter;
import com.thoughtworks.xstream.io.ExtendedHierarchicalStreamWriterHelper;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.mapper.Mapper;

/**
 * @author fuliang
 * 
 */
public class MapCustomConverter extends AbstractCollectionConverter {

    /**
	 * @param mapper
	 */
	public MapCustomConverter(Mapper mapper) {
		super(mapper);
	}

	public boolean canConvert(Class type) {
        return type.equals(HashMap.class)
                || type.equals(Hashtable.class)
                || type.getName().equals("java.util.LinkedHashMap")
                || type.getName().equals("sun.font.AttributeMap") // Used by java.awt.Font in JDK 6
                ;
    }

    public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) {
        Map map = (Map) source;
        for (Iterator iterator = map.entrySet().iterator(); iterator.hasNext();) {
            Entry entry = (Entry) iterator.next();
            ExtendedHierarchicalStreamWriterHelper.startNode(writer, "property", Entry.class);

            writer.addAttribute("key",  entry.getKey().toString());
            writer.addAttribute("value", entry.getValue().toString());
            writer.endNode();
        }
    }

    public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
        Map map = (Map) createCollection(context.getRequiredType());
        populateMap(reader, context, map);
        return map;
    }

    protected void populateMap(HierarchicalStreamReader reader, UnmarshallingContext context, Map map) {
        while (reader.hasMoreChildren()) {
            reader.moveDown();
            Object key = reader.getAttribute("key");
            Object value = reader.getAttribute("value");
            map.put(key, value);
            reader.moveUp();
        }
    }
}

然后这么使用：

XStream xStream = new XStream();
xStream.registerConverter(new MapCustomConverter(new DefaultMapper(XmlOutputFormatter.class.getClassLoader())));
xStream.alias("DataRecord", ExtractDataRecord.class);
xStream.alias("ExtractResult", ExtractResult.class);
xStream.alias("property", Entry.class);
return xStream.toXML(extractResult);

 

序列化后的结果很漂亮：

 

<ExtractResult>
  <dataRecords>
    <DataRecord>
      <properties>
        <property key="region" value="港澳"/>
        <property key="routeReference" value="搭乘国际航班直飞桃园国际机场，办理相关手续后，前往用晚餐。前往酒店入住休息。"/>
        <property key="routeDays" value="8"/>
        <property key="price" value="￥5680起"/>
        <property key="subject" value="常规"/>
        <property key="dayOfBookingExpired" value="2010-01-15"/>
        <property key="departure" value="北京"/>
        <property key="dayOfDeparture" value="2010-01-25"/>
        <property key="title" value="[团队游]台湾8日宝岛乡情之旅"/>
      </properties>
    </DataRecord>
  </dataRecords>
</ExtractResult>

评论

1 楼 widekk 2013-06-05  

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