如何在java中找到与输入匹配的正则表达式模式的一部分？

I have pattern "abc|de.|ghi" and an input of "def". How do I find the part of the pattern that matched "def"? So, in this example the result I want is "de.". Not "def", which is all I have been able to get using group and start/end methods.I have pattern "abc|de.|ghi" and an input of "d