如何在Java中制作没有任何for循环的String替换程序？

Question

For Example :-

String str = "Hello How are u!"

Replacement character with each other.

a one
e two
i three
o four
u five

OutPut

Htwollfour Hfourw onertwo five!

How do I do that without any looping ?

Answer 1

One way is to use a stream. And a map:

Map<Character, String> mapping = new HashMap<>();
mapping.put('a', "one");
mapping.put('e', "two");
mapping.put('i', "three");
mapping.put('o', "four");
mapping.put('u', "five");

String res = "Hello How are u!".chars()
        .mapToObj(ch -> mapping.getOrDefault((char) ch, 
                                  Character.toString((char) ch)))
        .collect(Collectors.joining());

System.out.println(res);

And that prints Htwollfour Hfourw onertwo five!