String#join
前回に引き続き、文字列の連結。
//String#joinメソッド。第一引数に区切り文字 //文字列連結 String joined = String.join(",", "a", "b", "c"); System.out.println(joined); //String配列の要素の連結 String[] arr = {"aa", "bb", "cc"}; String arrJoined = String.join(":", arr); System.out.println(arrJoined); //List<String> の要素の連結 List<String> list = Arrays.asList("aaa", "bbb", "ccc"); String listJoined = String.join("*", list); System.out.println(listJoined); //Streamを使用した場合 List<String> list2 = Arrays.asList("XX", "YY", "ZZ"); String listJoined2 = list2.stream().collect(Collectors.joining("|")); System.out.println(listJoined2);
結果
a,b,c aa:bb:cc aaa*bbb*ccc XX|YY|ZZ