Most elegant way to join a Map to a String in Java 8

by

You can grab the stream of the map’s entry set, then map each entry to the string representation you want, joining them in a single string using Collectors.joining(CharSequence delimiter).

import static java.util.stream.Collectors.joining;

String s = attributes.entrySet()
                     .stream()
                     .map(e -> e.getKey()+"="+e.getValue())
                     .collect(joining("&"));

But since the entry’s toString() already output its content in the format key=value, you can call its toString method directly:

String s = attributes.entrySet()
                     .stream()
                     .map(Object::toString)
                     .collect(joining("&"));

More Related Contents:

  1. In Java 8 how do I transform a Map to another Map using a lambda?
  2. How to force max to return ALL maximum values in a Java Stream?
  3. Java 8 Nested (Multi level) group by
  4. How to convert a Java 8 Stream to an Array?
  5. Should I return a Collection or a Stream?
  6. What is difference between Collection.stream().forEach() and Collection.forEach()?
  7. How to sum a list of integers with java streams?
  8. Group by and sum objects like in SQL with Java lambdas?
  9. Why does Stream not implement Iterable?
  10. How can I create a stream from an array?
  11. In Java 8, is there a ByteStream class?
  12. Sum values from specific field of the objects in a list
  13. Filter Java Stream to 1 and only 1 element
  14. Find maximum, minimum, sum and average of a list in Java 8
  15. Does Java SE 8 have Pairs or Tuples?
  16. Does Stream.forEach respect the encounter order of sequential streams?
  17. Most efficient way to get the last element of a stream
  18. Why does findFirst() throw a NullPointerException if the first element it finds is null?
  19. Java streams lazy vs fusion vs short-circuiting
  20. Collectors.summingInt() vs mapToInt().sum()
  21. Java 8 Stream IllegalStateException: Stream has already been operated on or closed
  22. How to check if a Java 8 Stream is empty?
  23. Stream Way to get index of first element matching boolean
  24. How to sum values in a Map with a stream?
  25. Is mapToDouble() really necessary for summing a List with Java 8 streams?
  26. Is it possible to cast a Stream in Java 8?
  27. ‘Optional.get()’ without ‘isPresent()’ check
  28. How to apply Filtering on groupBy in java streams
  29. Group sequences of values
  30. Java 8 stream map to list of keys sorted by values

Leave a Comment