如何在java中打印void
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how to print void in java
提问by upog
The below statement returns void
下面的语句返回 void
Pattern lazy = Pattern.compile("X??");
Matcher lazyMatcher = lazy.matcher("X");
if (lazyMatcher.matches()) {
System.out.println(lazyMatcher.group());
}
Is there way to print void in java.
有没有办法在java中打印void。
I tried below 2 statements , but does not help
我尝试了以下 2 条语句，但无济于事
System.out.println((String)lazyMatcher.group());
System.out.println(lazyMatcher.group().toString());
============================================================================= Updating
================================================== ============================ 更新
why am i getting String when i call below
为什么我在下面打电话时得到 String
System.out.println(lazyMatcher.group().getClass()) // returns string
System.out.println(lazyMatcher.group()) // returns void
采纳答案by Adam Arold
There is the Void.classyou can use.
If you try Void.class.toString()it will return
有Void.class你可以使用的。如果你尝试Void.class.toString()它会返回
class java.lang.Void
回答by Ben Green
void is not an object. All the void return type states is that nothing will be returned from the method. So the answer is no, there is no way to print void, as there is nothing to print.
void 不是一个对象。所有 void 返回类型状态是该方法不会返回任何内容。所以答案是否定的，没有办法打印 void，因为没有什么可打印的。
With regards to your edited question, you are getting a String because Matcher.group() returns a string not void. See the documentation
关于您编辑的问题，您得到一个字符串，因为 Matcher.group() 返回一个不为空的字符串。查看文档
回答by smerlung
void is nothing. You don't print it. If you wan't to print "void" you can do
空是什么。你不打印。如果你不想打印“void”，你可以做
System.out.println("void");
回答by Aneesh
You cant print something that isn't there.
你不能打印不存在的东西。
