如何测试文本字段值是否是有效的电子邮件？ [复制]

Question

可能重复：
What is the best regular expression for validating email addresses?

我想测试用户是否输入了有效的电子邮件格式。如何在 J2ME 中编写代码？

Answer 1

对于对可能正确的正则表达式来解析电子邮件地址感兴趣的人：这是 afaik 正确的一些 perl 模块的代码（但我不知道如何验证它，所以我只是重复其他人，希望受过更多教育的人声称）：

准备好了吗？好的，我们开始：

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Answer 2

为 J2ME 使用第三方正则表达式库。例如：regexp-me 或 dk.brics.automaton 使用可用的许多正则表达式之一来验证它（如 Regular expressions in J2ME 中所建议的那样）。比如What is the best regular expression for validating email addresses?中的那些。

或使用此问题答案中建议的代码 sn-p：Is there email validator code for Java ME or BlackBerry?。

Wicket Framework 有简单的EmailAddressValidator，到目前为止对我来说效果很好。它使用以下正则表达式，使用Pattern.compile 中的Pattern.CASE_INSENSITIVE 标志：

"^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9-]+)*((\\.[A-Za-z]{2,}){1}$)"

它还有一个符合RFC-822 的验证器：RfcCompliantEmailAddressValidator。而here 是符合RFC-2822 的正则表达式。这似乎是关于电子邮件地址的最新规范。

您可能会使用简单的验证器，但不使用简单验证器验证但使用符合 RFC 的验证器进行验证的地址也可能是用户错误。

Answer 3

使用正则表达式。这里有一个blog post 来告诉你怎么做。来自博文：

public boolean isValidEmailAddress(String emailAddress){  
   String  expression="^[\\w\\-]([\\.\\w])+[\\w]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";  
   CharSequence inputStr = emailAddress;  
   Pattern pattern = Pattern.compile(expression,Pattern.CASE_INSENSITIVE);  
   Matcher matcher = pattern.matcher(inputStr);  
   return matcher.matches();  

 } 

由于您在 J2ME 平台上并且无法访问 Java 的正则表达式，您可以尝试名为 regexp-me 的第三方库。