前端外刊评论 2018-05-29
场景:将一个层级类对象(领域驱动model对象)转换为平铺类对象(view)
src对象,(红框为子对象)
target对象(平铺对象)
代码思路,先递归反射遍历出所有字段,存到一个map里,再递归赋值给target对象
缺陷:不同子对象间的同名字段会被覆盖成一个值
代码
private static void getSrcALLFieldMap(Object obj,Map<String,Object> collectMap){ Class srcClazz = obj.getClass(); Field[] srcFields = srcClazz.getDeclaredFields(); Stream.of(srcFields).forEach(field -> { field.setAccessible(true); try { if(field.getType().toString().contains("aacoin.account") && !field.getType().isEnum()){ Object subObj = field.get(obj); if(subObj!=null) getSrcALLFieldMap(subObj,collectMap); }else{ collectMap.put(field.getName(),field.get(obj)); } } catch (IllegalAccessException e) { e.printStackTrace(); } }); } private static void setTargetAllField(Object obj, Map<String,Object> srcMap){ Class srcClazz = obj.getClass(); Field[] srcFields = srcClazz.getDeclaredFields(); Stream.of(srcFields).forEach(field -> { field.setAccessible(true); try { if(field.getType().toString().contains("aacoin.trade.otc") && !field.getType().isEnum()){ Object subObj = field.get(obj); if(subObj == null) { Constructor cons = field.getType().getDeclaredConstructor(null); cons.setAccessible(true); subObj = cons.newInstance(null); field.set(obj, subObj); } setTargetAllField(subObj, srcMap); }else{ //collectMap.put(field,obj); Object currentField = srcMap.get(field.getName()); if( currentField !=null && field.getType() == currentField.getClass()){ field.set(obj,currentField); } } } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } }); } public static <T> T convert(Object src,Class<T> tClass){ Constructor<T> cons = null; try { cons = tClass.getDeclaredConstructor(null); } catch (NoSuchMethodException e) { e.printStackTrace(); } cons.setAccessible(true); T result = null; try { result = cons.newInstance(null); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } convert(src,result); return result; } public static <T> T convert(Object src,T result) { Map<String,Object> srcMap = new HashMap(); getSrcALLFieldMap(src,srcMap); setTargetAllField(result,srcMap); return result; }
调用:
adverVO =convert(advert,AdvertVO.class);<br /><br />写的比较随意,直接吞掉了异常,需自行处理,将异常统一规范抛出
class Singleton: def __new__: # 关键在于这,每一次实例化的时候,我们都只会返回这同一个instance对象 if not hasattr: cls.instance =