从 c# 到java

refs:

http://stackoverflow.com/questions/6219773/is-there-any-keyword-in-java-which-is-similar-to-the-as-keyword-of-c-sharp

C# 有 as is 方便转换,java没有

只有这个

public static T as(Object o, Class<T> tClass) {     return tClass.isInstance(o) ? (T) o : null;}User user = as(obj, User.class);