复制对象属性时用到apache common-beanutils这个工具包中的
BeanUtils.copyProperties
但经测试100W次复制单一属性的对象用了2354豪秒,这是因为通过JDK的method.invoke去反射调用方法复制对象中的属性,用http://code.google.com/p/reflectasm/这个工具包可以提高性能
public class BeanUtils { private static Map<Class,MethodAccess> methodMap = new HashMap<Class,MethodAccess>(); private static Map<String,Integer> methodIndexMap = new HashMap<String,Integer>(); private static Map<Class,List<String>> fieldMap = new HashMap<Class,List<String>>(); public static void copyProperties(Object desc,Object orgi){ MethodAccess descMethodAccess = methodMap.get(desc.getClass()); if(descMethodAccess == null){ descMethodAccess = cache(desc); } MethodAccess orgiMethodAccess = methodMap.get(orgi.getClass()); if(orgiMethodAccess == null){ orgiMethodAccess = cache(orgi); } List<String> fieldList = fieldMap.get(orgi.getClass()); for (String field : fieldList) { String getKey = orgi.getClass().getName() + "." + "get" + field; String setkey = desc.getClass().getName() + "." + "set" + field; Integer setIndex = methodIndexMap.get(setkey); if(setIndex != null){ int getIndex = methodIndexMap.get(getKey); descMethodAccess.invoke(desc, setIndex.intValue(), orgiMethodAccess.invoke(orgi, getIndex)); } } } private static MethodAccess cache(Object orgi){ synchronized (orgi.getClass()) { MethodAccess methodAccess = MethodAccess.get(orgi.getClass()); Field[] fields = orgi.getClass().getDeclaredFields(); List<String> fieldList = new ArrayList<String>(fields.length); for (Field field : fields) { if(Modifier.isPrivate(field.getModifiers()) && ! Modifier.isStatic(field.getModifiers())){ //非公共私有变量 String fieldName = StringUtils.capitalize(field.getName()); int getIndex = methodAccess.getIndex("get"+fieldName); int setIndex = methodAccess.getIndex("set"+fieldName); methodIndexMap.put(orgi.getClass().getName()+"."+"get"+fieldName, getIndex); methodIndexMap.put(orgi.getClass().getName()+"."+"set"+fieldName, setIndex); fieldList.add(fieldName); } } fieldMap.put(orgi.getClass(),fieldList); methodMap.put(orgi.getClass(), methodAccess); return methodAccess; } } }
用此方法运行100W次,大约用时800毫秒,约相差3倍.