如何在Java中模拟C＃as-operator [英] How to emulate C# as-operator in Java

问题描述

在某些情况下，使用类型转换返回一个空值是很实际的，而不是抛出一个ClassCastException。 C＃有作为运算符来执行此操作。在Java中有一些等价的东西，所以你不必显式检查ClassCastException？

There are situations, where it is practical to have a type-cast return a null value instead of throwing a ClassCastException. C# has the as operator to do this. Is there something equivalent available in Java so you don't have to explicitly check for the ClassCastException?

推荐答案

，如@Omar Kooheji所建议：

Here's an implementation of as, as suggested by @Omar Kooheji:

public static <T> T as(Class<T> clazz, Object o){
    if(clazz.isInstance(o)){
        return clazz.cast(o);
    }
    return null;
}

as(A.class, new Object()) --> null
as(B.class, new B())  --> B

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