在点 (.) 上拆分字符串，除非它出现在 Java 中使用正则表达式的分数中

Question

As the title says, I want to split a string using java regex based on dot but only if the dot appears in between alphabets.

Lets say the string is:

System.out.println(5.55);

I need output as

System
out
println(5.55);

Answer 1

Simply use lookahead and lookbehind like this

System.out.println(Arrays.toString("System.out.println(5.55);".split("(?<=\\D)\\.(?=\\D)")));

For further reference what they actually do you could read through this

Answer 2

A lookbehind and lookahead for letters is probably what you want. DEMO

(?<=[a-zA-Z])\.(?=[a-zA-Z])

String content = "asdf.qweflkjasdf.qweflasdfasfd55.523";
Pattern p = Pattern.compile("(?<=[a-zA-Z])\\.(?=[a-zA-Z])");           
System.out.println(p.matcher(content).replaceAll("\n"));

OUTPUT:
asdf
qweflkjasdf
qweflasdfasfd55.523