Java 可变参数可以为空吗？
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Can a Java varargs be null?
提问by Supuhstar
I found myself checking for this and asking if it's necessary. I have code like this:
我发现自己正在检查这个并询问是否有必要。我有这样的代码：
public Object myMethod(Object... many) {
if (many == null || many.length == 0)
return this;
for (Object one : many)
doSomethingWith(one);
return that;
}
But then I wondered... Am I being too cautious? Do I have to check if many == null? Is that ever possible in any current Java version?If so, how? If not, I'll probably keep checking, just for futureproofing in case Oracle decides it can be null one day.
但后来我想知道……我是不是太谨慎了？我必须检查many == null吗？在任何当前的 Java 版本中都可能吗？如果是这样，如何？如果没有，我可能会继续检查，以防将来 Oracle 决定它可以为空。
回答by Dave
I tried it with Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0 on Linux 3.5.0-21-generic
我试过了 Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0 on Linux 3.5.0-21-generic
Using myMethod(null)doesn't pass new Object[]{null}, it passes null. Arrays are objects in Javaand therefore nullis valid for the type Object[].
使用myMethod(null)不通过new Object[]{null}，它通过null。数组是 Java 中的对象，因此null对类型有效Object[]。
Your nullcheck is, therefore, not overly cautious.
因此，您的空检查并不过分谨慎。
