检查字符串中的非数字字符 [英] Check non-numeric characters in string

问题描述

我想检查字符串是否仅包含数字字符或它也包含字母数字字符.

I want to check whether the String contains only numeric characters or it contains alpha-numeric characters too.

我必须在数据库事务中实施此检查，该事务将要获取并通过该检查传递约十万条记录，因此我需要优化性能的答案.

I have to implement this check in database transaction where about a hundred-thousand records are going to be fetched and passed through this check, so I need optimized performance answer.

当前，我已经通过try-catch块实现了这一点:我在try块中的Integer中解析了字符串，并在catch块中检查了NumberFormatException.请提出建议，如果我错了.

Currently, I have implemented this through a try-catch block: I parsed the string in Integer in try block and checked for the NumberFormatException in the catch block. Please suggest if I'm wrong.

推荐答案

您可以使用正则表达式进行检查.

You can check this with a regex.

假设(仅数字值):

String a = "493284835";
a.matches("^[0-9]+$"); // returns true

假设(仅字母数字值):

Suppose that (alphanumeric values only):

String a = "dfdf4932fef84835fea";
a.matches("^([A-Za-z]|[0-9])+$"); // returns true

正如Pangea在评论区所说:

As Pangea said in the comments area :

如果性能至关重要，则最好编译正则表达式.参见下面的示例:

If the performance are critical, it's preferrable to compile the regex. See below for an example :

String a = "dfdf4932fef84835fea";
Pattern pattern = Pattern.compile("^([A-Za-z]|[0-9])+$");
Matcher matcher = pattern.matcher(a);

if (matcher.find()) {
    // it's ok
}

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