【Java】Bean复制几种实现方法性能比较

Apache 的BeanUtils    9431
Apache 的PropertyUtils    8083
Spring 的BeanUtils    4827
反射工具包ReflectASM 自定义工具类    4777

//利用反射工具包ReflectASM自定义工具类
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);
// 参数一需要反射的对象
// 参数二class.getDeclaredMethods 对应方法的index
// 参数对三象集合
descMethodAccess.invoke(desc, setIndex.intValue(),
orgiMethodAccess.invoke(orgi, getIndex));
}
}
}

// 单例模式
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())) { // 是否是私有的，是否是静态的
// 非公共私有变量
String fieldName = StringUtils.capitalize(field.getName()); // 获取属性名称
int getIndex = methodAccess.getIndex("get" + fieldName); // 获取get方法的下标
int setIndex = methodAccess.getIndex("set" + fieldName); // 获取set方法的下标
methodIndexMap.put(orgi.getClass().getName() + "." + "get"
+ fieldName, getIndex); // 将类名get方法名，方法下标注册到map中
methodIndexMap.put(orgi.getClass().getName() + "." + "set"
+ fieldName, setIndex); // 将类名set方法名，方法下标注册到map中
fieldList.add(fieldName); // 将属性名称放入集合里
}
}
fieldMap.put(orgi.getClass(), fieldList); // 将类名，属性名称注册到map中
methodMap.put(orgi.getClass(), methodAccess);
return methodAccess;
}
}

}

/**
* 测试方法：将查出的商品实体数据利用不同工具包下的方法拷贝至一个新的传输实体
* 商品数据量：八万左右
*/
public long costSeconds() {
List<ShopGoodsDTO> shopGoodsDTOList=new ArrayList<>();
ShopGoodsExample shopGoodsExample = new ShopGoodsExample();
shopGoodsExample.createCriteria().andStoreIdEqualTo(743);
// 查询到的商品数据
List<ShopGoods> shopGoodsList = shopGoodsMapper.selectByExample(shopGoodsExample);
long costSeconds=0L;
if(shopGoodsList!=null && shopGoodsList.size()>0){
long startTime=System.currentTimeMillis();
for (ShopGoods shopGoods:shopGoodsList) {
ShopGoodsDTO shopGoodsDTO = new ShopGoodsDTO();
BeanUtils.copyProperties(shopGoodsDTO,shopGoods);
//org.springframework.beans.BeanUtils.copyProperties(shopGoods,shopGoodsDTO);
//BeanUtils.copyProperties(shopGoodsDTO,shopGoods);
// try {
// PropertyUtils.copyProperties(shopGoodsDTO,shopGoods);
// } catch (NoSuchMethodException e) {
// e.printStackTrace();
// }
System.out.println(new Gson().toJson(shopGoodsDTO));
shopGoodsDTOList.add(shopGoodsDTO);
}
long endTime=System.currentTimeMillis();
costSeconds=endTime-startTime;
}
return costSeconds;
}