使用轻量级的XStream可以很方便的将对象序列化为XML
此外，XStream还可自定义序列化和反序列的转换器(Converter)
下面的转换器可将Map/List序列化，或将其他POJO的序列化XML反转为Map/List
直接上代码 PojoMapConverter.java
<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> package net.cnlab.vo.services.xstream; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.Entry; import com.thoughtworks.xstream.converters.Converter; import com.thoughtworks.xstream.converters.MarshallingContext; import com.thoughtworks.xstream.converters.UnmarshallingContext; import com.thoughtworks.xstream.io.HierarchicalStreamReader; import com.thoughtworks.xstream.io.HierarchicalStreamWriter; public class PojoMapConverter implements Converter { public PojoMapConverter() { super (); } public boolean canConvert(Class clazz) { String classname = clazz.getName(); if (classname.indexOf( " Map " ) >= 0 || classname.indexOf( " List " ) >= 0 || classname.indexOf( " Bean " ) >= 0 ) return true ; else return false ; } public void marshal(Object value, HierarchicalStreamWriter writer, MarshallingContext context) { map2xml(value, writer, context); } protected void map2xml(Object value, HierarchicalStreamWriter writer, MarshallingContext context) { boolean bMap = true ; String classname = value.getClass().getName(); bMap = (classname.indexOf( " List " ) < 0 ); Map < String, Object > map; List < Object > list; String key; Object subvalue; if (bMap) { map = (Map < String, Object > ) value; for (Iterator < Entry < String, Object >> iterator = map.entrySet() .iterator(); iterator.hasNext();) { Entry < String, Object > entry = (Entry < String, Object > ) iterator .next(); key = (String) entry.getKey(); subvalue = entry.getValue(); writer.startNode(key); if (subvalue.getClass().getName().indexOf( " String " ) >= 0 ) { writer.setValue((String) subvalue); } else { map2xml(subvalue, writer, context); } writer.endNode(); } } else { list = (List < Object > ) value; for (Object subval : list) { subvalue = subval; writer.startNode( " child " ); if (subvalue.getClass().getName().indexOf( " String " ) >= 0 ) { writer.setValue((String) subvalue); } else { map2xml(subvalue, writer, context); } writer.endNode(); } } } public Map < String, Object > unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) { Map < String, Object > map = (Map < String, Object > ) populateMap(reader, context); return map; } protected Object populateMap(HierarchicalStreamReader reader, UnmarshallingContext context) { boolean bMap = true ; Map < String, Object > map = new HashMap < String, Object > (); List < Object > list = new ArrayList < Object > (); while (reader.hasMoreChildren()) { reader.moveDown(); String key = reader.getNodeName(); Object value = null ; if (reader.hasMoreChildren()) { value = populateMap(reader, context); } else { value = reader.getValue(); } if (bMap) { if (map.containsKey(key)) { // convert to list bMap = false ; Iterator < Entry < String, Object >> iter = map.entrySet() .iterator(); while (iter.hasNext()) list.add(iter.next().getValue()); // insert into list list.add(value); } else { // insert into map map.put(key, value); } } else { // insert into list list.add(value); } reader.moveUp(); } if (bMap) return map; else return list; } }
通过XStream中注册该转换器，即可用toXML和fromXML转换
使用示例，将xml转为Map/List，然后再转换为xml
<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ --> public static void main(String[] args) { String xml = " <map><stars><star><id>1</id><name>littleflower</name></star><star><id>2</id><name>littleyellow</name></star></stars> <filename>cnlab</filename> <ra>147.0</ra> <dec>0.0</dec> <plate>0.0</plate> <mdj>0.0</mdj> </map> " ; XStream xstream = new XStream( new DomDriver()); xstream.registerConverter( new PojoMapConverter()); Map < String, Object > map = (Map < String, Object > )xstream.fromXML(xml); System.out.println(map); xml = xstream.toXML(map); System.out.println(xml); System.out.println((Map < String, Object > )xstream.fromXML(xml));