How to Join a List of Strings By a Delimiter in Java
Suppose we have an
ArrayList, and we want to join all the elements together by some character, or delimiter.
List<String> list = Arrays.asList("a","b","c");
Let’s say we want to join these elements with commas to create the string:
1. Join a list using
We can easily use
String.join() to concatenate multiple strings by a delimiter, which is specified in the first parameter.
String res = String.join(",", list);
2. Join a list using the Stream API
We can use the Stream API’s
Collectors.joining() method to achieve the same functionality.
String res = list.stream().collect(Collectors.joining(","));
3. Join a list using
The third option is to scrap the list entirely.
If we know that all we want to do is join the elements into a string, then we can use
StringJoiner from the get-go.
StringJoiner joiner = new StringJoiner(","); joiner.add("a"); joiner.add("b"); joiner.add("c"); String res = joiner.toString();