Shulou(Shulou.com)06/03 Report--

This article is mainly used to record the use of XStream, especially the "object default value" and the use of Map converter.

1, add Maven dependency

Com.thoughtworks.xstream xstream 1.4.11.1

2, create an object that can use default values

Import java.lang.reflect.Field;import com.thoughtworks.xstream.converters.reflection.ObjectAccessException;import com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider The instance of public class FieldDefaultValueProvider extends PureJavaReflectionProvider {/ * @ param object target class * @ param fieldName XML displays the specified field * @ param definedIn parent class or the class itself * / @ Override public void writeField (Object object, String fieldName, Object value, Class definedIn) {Field field = fieldDictionary.field (object.getClass (), fieldName, definedIn); / / returns the field validateFieldAccess (field) that exists in xml / / the verification field can be accessed try {if (value instanceof String) {String trim = ((String) value) .trim (); / / empty if at the beginning and end of the string (trim.length () = = 0) / / if it is an empty string, no assignment is made, using the default initial value return; field.set (object,trim) } else {field.set (object, value);}} catch (IllegalArgumentException e) {throw new ObjectAccessException ("Could not set field" + object.getClass () + "." + field.getName (), e) } catch (IllegalAccessException e) {throw new ObjectAccessException ("Could not set field" + object.getClass () + "." + field.getName (), e);}

3, create an object for transforming Map

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 Public class MapCustomConverter extends AbstractCollectionConverter {public MapCustomConverter (Mapper mapper) {super (mapper);} @ Override 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") } @ Override 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 ();} @ Override 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 ();}

4, create a XStream object

Private static XStream getXStream () {/ / XStream xstream = new XStream (); / requires XPP3 library / / XStream xstream = new XStream (new DomDriver ()); / / does not need XPP3 library / / XStream xstream = new XStream (new StaxDriver ()); / / does not need XPP3 library to start using Java6 XStream xstream = new XStream (new FieldDefaultValueProvider (), new DomDriver ()); / / creates Xstram object xstream.autodetectAnnotations (true) Xstream.addPermission (AnyTypePermission.ANY); xstream.registerConverter (new MapCustomConverter (new ClassLoaderReference (XStream.class.getClassLoader (); XStream.setupDefaultSecurity (xstream); xstream.allowTypes (new Class [] {CollectTaskMeta.class, FtpConfig.class, TaskParallel.class, TaskRootConfig.class, Sql.class})) Xstream.processAnnotations (new Class [] {CollectTaskMeta.class, FtpConfig.class, TaskParallel.class, TaskRootConfig.class, Sql.class}); return xstream;}

5. Use XStream to parse the file

Import org.springframework.util.ResourceUtils;XStream xstream = getXStream (); TaskRootConfig meteInfo = null;try {meteInfo = (TaskRootConfig) xstream.fromXML (ResourceUtils.getFile ("classpath:taskconfig.xml"));} catch (FileNotFoundException e) {e.printStackTrace ();}

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.