XStream Converter Date

类如下：

public class bookinfo implements java.io.Serializable
{
  private Long id;
  
     //Fields
     private java.lang.Long bsno;
     private java.lang.String bookname;
     private java.lang.String isbn;
     private java.lang.String booktype;
     private java.lang.String author;
     private java.util.Date publishdate;
     private java.lang.Long quantityperpackage;
     private java.lang.Long height;

}

在bookinfo中的publishdate是一个date对象，在用XStream做转换的时，由于XStream自带的DateConverter  不能转换形如“2010-10-07”这样的日期格式，只能自定义一个转换器

public class DateConverter  implements Converter {

 @Override
 public boolean canConvert(Class arg0) {

  return Date.class == arg0;
 }
 @Override
 public void marshal(Object arg0, HierarchicalStreamWriter arg1,
   MarshallingContext arg2) {

  
 }
 @Override
 public Object unmarshal(HierarchicalStreamReader reader,
   UnmarshallingContext arg1) {
        GregorianCalendar calendar = new GregorianCalendar(); 
        SimpleDateFormat dateFm = new SimpleDateFormat("yyyy-MM-dd"); //格式化当前系统日期
        try {
                calendar.setTime(dateFm.parse(reader.getValue()));
        } catch (ParseException e) {
                throw new ConversionException(e.getMessage(), e);
        } 
        return calendar.getTime();

 }

 }

最后在程序中注册构造的转换器。。。。

   XStream xstream = new XStream(new DomDriver());
   xstream.registerConverter(new DateConverter());

同样的，在从XML向java对象转换时，如果Long对应的是空字符串，Xstream也会报错，例如，XML文件中如果quantityperpackage的值为空，则转换为Long时会报错，则，同样的编写转换器，在转换器中判断，如果XML中对应的为空，则让Long等于null。

对象的转换器如下：

public class LongConverter  implements Converter {

 @Override
 public boolean canConvert(Class arg0) {

  return Long.class == arg0;
 }
 @Override
 public void marshal(Object arg0, HierarchicalStreamWriter arg1,
   MarshallingContext arg2) {

  
 }
 @Override
 public Object unmarshal(HierarchicalStreamReader reader,
   UnmarshallingContext arg1) {
  Long longnum = new Long("1");
  System.out.println(reader.getValue());
        if("".equals(reader.getValue()))
        {
         System.out.println("long is null");
         longnum = null;
         return longnum;
        }
        else{
         longnum = longnum.valueOf(reader.getValue());
         System.out.println("long is not null");
            return longnum;
        }
       

 }

}

同样在程序中注册构造的转换器。。。。

   XStream xstream = new XStream(new DomDriver());
   xstream.registerConverter(new LongConverter());