[20210224] StringUtils defaultString, StringJoiner

[JuHyun419]

apache commons - StringUtils.defaultString()

    // pom.xml
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.8.1</version>
    </dependency>


    public static String defaultString(String str) {
        return defaultString(str, "");
    }

    public static String defaultString(String str, String defaultStr) {
        return str == null ? defaultStr : str;
    }

StringJoiner(Java8 util) ... String의 join과 비슷

    public static String solution(String s) {
        String[] sSplit = s.split(" ");
        StringJoiner stringJoiner = new StringJoiner(",");

        for (String str : sSplit) {
            String firstWordToUpper = str.substring(0, 1).toUpperCase();
            String otherWord = str.substring(1).toLowerCase();
            stringJoiner.add(firstWordToUpper + otherWord);
        }

        return stringJoiner.toString();
    }

    public static void main(String[] args) {
        String str = "3people unFollowed me";
        System.out.println(solution(str));
    }

3people,Unfollowed,Me