您的问题有点模棱两可。

Your question is a little ambiguous.

如果您只想知道字符串是否包含字母或数字（但可能仅 字母或 数字）没有别的，那么正则表达式：

If you just want to know whether the string contains letters or numbers (but perhaps only letters or only numbers) and nothing else, then the regex :

pass.matches("^[a-zA-Z0-9]+$");

将返回true。

如果你想检查它是否包含两个字母和数字，没有别的，那么它更复杂，但是类似于：

If you want to check whether it contains both letters and numbers, and nothing else, then it is more complex, but something like:

pass.matches("^[a-zA-Z0-9]*(([a-zA-Z][0-9])|([0-9][a-zA-Z]))[a-zA-Z0-9]*$");

所有***的