Java 中正整数的正则表达式（不包括以零开头的那些）
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/5998247/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Regular expression in Java for positive integers (excluding those starting with zero)
提问by skyork
I currently use "(\d){1,9}", but it fails to invalidate numbers such as "0134". The expression must only validate numbers that are positive INTEGERS. Thanks.
我目前使用“(\d){1,9}”，但它无法使诸如“0134”之类的数字无效。该表达式必须仅验证正整数的数字。谢谢。
回答by Roland Illig
Right now you use the expression [0-9]{1,9}, so this clearly allows the number 0134. When you want to require that the first character is not a zero, you have to use [1-9][0-9]{0,8}.
现在您使用表达式[0-9]{1,9}，所以这显然允许数字0134。当您想要求第一个字符不是零时，您必须使用[1-9][0-9]{0,8}.
By the way: 0134 isa positive integer. It is an integer number, and it is positive. ;)
顺便说一句：0134是一个正整数。它是一个整数，并且是正数。;)
edit:
编辑：
To prevent integer overflow you can use this pattern:
为了防止整数溢出，您可以使用以下模式：
[1-9][0-9]{0,8}[1-1][0-9]{9}[2-2][0-1][0-9]{8}[2-2][1-1][0-3][0-9]{7}[2-2][1-1][4-4][0-6][0-9]{6}- …
[1-9][0-9]{0,8}[1-1][0-9]{9}[2-2][0-1][0-9]{8}[2-2][1-1][0-3][0-9]{7}[2-2][1-1][4-4][0-6][0-9]{6}- …
I think you get the idea. Then you combine these expressions with |, and you are done.
我想你应该已经明白了。然后将这些表达式与 组合在一起|，就大功告成了。
Alternatively, have a look at the Integer.valueOf(String)method, how it parses numbers and checks for overflow. Copy that code and change the part with the NumberFormatException.
或者，看看该Integer.valueOf(String)方法，它如何解析数字并检查溢出。复制该代码并使用NumberFormatException.
回答by manojlds
You can use a regex like below:
您可以使用如下正则表达式：
^(?!^0)\d{1,9}$
What you mean to say is positive integers without leading zeroesI believe.
你的意思是我相信没有前导零的正整数。
