How to get a list of properties with the same level?

Question

Java

Hello, please help me answer the following question.
There is a familiar application.property file. It stores properties in the following form:
propLevel1.data1
propLevel1.data2
propLevel2.data1
propLevel2.data2
How can you get a list of properties that start with propLevel1.* without "extra blood"? Most likely, there are already ready-made solutions that I cannot find.

Answer 1

If these are Java properties, and we use Java 8, then you can try this

Properties props = new Properties() //как-то в общем мы получили сей объект, это не важно
List<String> vals = props.stringPropertyNames().stream().filter(key -> key.startWith("propLevel1")).map(props::getProperty).collect(Collectors.toList());