将Javascript正则表达式转换为Java语法 [英] Convert Javascript regular expression to Java syntax

问题描述

我知道regEx在各种语言中很常见......但是我在编写Java语法时遇到了麻烦。
我有一个用JS编码的正则表达式;

I am aware that regEx are common across languages...But I am having trouble in writing the Java syntax. I have a regular expression coded in JS as;

if((/[a-zA-Z]/).test(str) && (/[0-9]|[\x21-\x2F|\x3A-\x40|\x5B-\x60|\x7B-\x7E]/).test(str))         
return true;

如何在Java中编写相同的内容？

How do I write the same in Java ?

我已导入

import java.util.regex.Matcher;
import java.util.regex.Pattern;

只是添加，我正在尝试它是说\ x是一个无效的转义字符。 。

Just to add, from what I am trying it is saying \x is an invalid escape character..

推荐答案

将前导和尾随'/'字符更改为''，然后用\\替换每个'\' 。

Change the leading and trailing '/' characters to '"', and then replace each '\' with "\\".

与Javascript，Perl和其他脚本语言不同，Java没有针对正则表达式的特殊语法。相反，它们是（通常使用Java字符串文字表示。但'\'是Java字符串文字中的转义字符，因此每个'\'必须使用第二个'\'进行转义。（如果你在正则表达式中有一个字面反斜杠字符，你最终会得到Java字符串文字中的\\\\ !!）

Unlike, Javascript, Perl and other scripting languages, Java doesn't have a special syntax for regexes. Instead, they are (typically) expressed using Java string literals. But '\' is the escape character in a Java string literal, so each '\' in the original regex has to be escaped with a 2nd '\'. (And if you have a literal backslash character in the regex, you end up with "\\\\" in the Java string literal!!)

这是一点点让Java新手感到困惑/畏惧......但这完全是合乎逻辑的。记住这一点在你使用Java字符串文字来表达正则表达式。

This is a bit confusing / daunting for Java novices ... but it is totally logical. Just remember that you are using a Java string literal to express the regex.

然而正如@antak所说，两者之间存在各种差异Java和Javascript中的正则表达式语言。因此，如果您使用Javascript正则表达式并将其音译为Java，则可能无效。

However as @antak notes, there are various differences between regex languages in Java and Javascript. So if you take a Javascript regex and transliterate it to Java as above, it might not work.

以下是一些总结差异的参考资料。

Here are some references that summarize the differences.

• https://en.wikipedia.org / wiki / Comparison_of_regular_expression_engines


• https：// gist。 github.com/CMCDragonkai/6c933f4a7d713ef712145c5eb94a1816

• https://en.wikipedia.org/wiki/Comparison_of_regular_expression_engines
• https://gist.github.com/CMCDragonkai/6c933f4a7d713ef712145c5eb94a1816

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