Java正则表达式字符串替换

Question

I am trying to write regex for replacing string.

There are string examples:

I am student.

I <a href="am.html">am</a> student.

I want to write regex which will replace "am" with <a> html tag, and get second string as result of replacing the first string.

Problem is nesting in quotes and text inside tag.

For example if I try to replace string "am" in this example:

I <a href="am.html">am</a> am student.

Result should be:

I <a href="am.html">am</a> <a href="am.html">am</a> student.

Thanks in advance!

Answer 1

如果是这样的简单情况，则可以使用简单的环顾四周方法来确保所匹配的事物没有被>和<包围，但是它周围有单词边界（ \\b ）：

(?<!>)\bam\b(?!<)

Answer 2

下面的正则表达式匹配的只有am的空白包围。

str.replaceAll("(?<=\\s)am(?=\\s)","<a href=\"am.html\">am</a>")

Answer 3

I can see some answers related to regex string posted already so there's no need for me to post another one. But as for this simple case, how about something as simple as replacing String? Or perhaps the real problem is more complicated than this? My solution for this case is:

s.replaceAll(" am ", " <a href=\"am.html\">am</a> ");