英文:
How do you get the type of a primitive literal in Java?
问题
我刚刚了解到在长整型数值后面使用"L"来表示它们是长整型，就像在浮点数类型后面使用"f"一样。我想知道当你写成：
long value = 3;
而不是
long value = 3L;
会发生什么。
所以我在想：
编译器会将3视为整数，然后隐式地转换为长整型吗？
然后我尝试使用 instanceof 来检查值为"3"的类型（但我不能使用它，因为它是原始类型），或者使用反射（getClass()，但显然我不能因为它不是引用类型）。有没有办法检查值"3"的类型，或者由于Java是静态类型语言，这是不可能的？
谢谢，
Bernard
英文:
I just learned about using "L" after long values to signify that they're long types, just like when you use "f" after float types. I was wondering what happens when you write;
long value = 3;
instead of
long value = 3L;
So I was wondering;
Does the compiler consider 3 an integer and then just convert it implicitly to a long?
Then I tried to check the type of the value "3" by using instanceof (but I can't use it since it is a primitive type) or reflection (getClass(), but obviously I can't because it isn't a reference type). Is there anyway to check what type the value "3" is or is this impossible since Java is statically typed?
Thanks,
Bernard
答案1
得分: 1
根据Java 14语言规范的第3.10.1节 整数字面值：
> 如果整数字面值以ASCII字母L或l（小写的L）作为后缀，则其类型为long；否则其类型为int（参见§4.2.1）。
英文:
According to section 3.10.1 Integer Literals of the Java 14 Language Specification:
> An integer literal is of type long if it is suffixed with an ASCII letter L or l (ell); otherwise it is of type int (§4.2.1).
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