Being a programmer, at some point of time we encountered a situation in which you wanted to join (not concat) multiple strings of delimited items in Java. Worst can be if you are provided multiple string literals. Just think for a second and how will you build a string of delimited items using these literals. Eg.<\/p>\n
[java]
\nString str1 = "java";
\nString str2 = "scala";
\nString str3 = "groovy";<\/p>\n
StringBuilder sb = new StringBuilder();
\nsb.append(str1).append(",").append(str2).append(",").append(str3);
\nsb.toString();<\/p>\n
[\/java]<\/p>\n
Or, many times we find ourselves in a situation where you want to pass a collection to IN clause of HQL or SQL. In this era of programming this is how we do this so obvious work<\/p>\n
[java]
\n\/\/ List<String> listOfNames = ….
\n StringBuilder sbObj = new StringBuilder();
\n for (String str : listOfNames) {
\n if (sbObj.length() > 0) {
\n sbObj.append(‘,’);
\n }
\n sbObj.append(str);
\n }
\n sbObj.toString();<\/p>\n
[\/java]<\/p>\n
Code reviewer will acquit you due to lack of good solutions evidence. But not anymore, In Java 8 we finally can join Strings with ease.<\/p>\n
StringJoiner\u00a0is a class added in Java 8. As the name suggests, we can use this class to join strings. There are two constructors, one taking the separator (delimiter) and one allowing a prefix and suffix.<\/p>\n
1.\u00a0StringJoiner(CharSequence delimiter)<\/strong><\/span><\/p>\n [java] \/\/ add() calls can be chained 2. StringJoiner(CharSequence delimiter, CharSequence prefix, CharSequence suffix)<\/strong><\/span><\/p>\n The String like “[Richard:Gilfoyle:Erlich]” may be constructed as follows:<\/p>\n [java] Moreover, StringJoiner is used as a behind scene tool by the two new static join()\u00a0<\/span><\/strong>methods of String class<\/strong><\/span>:<\/p>\n \/\/ \u00a0join(CharSequence delimiter, CharSequence… elements)<\/strong><\/span><\/p>\n [java] \/\/ join(CharSequence delimiter, Iterable<? extends CharSequence> elements)<\/strong><\/span><\/p>\n [java] A new joining Collector is also available for the new Stream API:<\/p>\n [java] String joinedFirstNames = list.stream() \/\/ "Richard, Erlich, Jared"<\/p>\n [\/java]<\/p>\n Now, \u00a0join string smartly \ud83d\ude09<\/p>\n","protected":false},"excerpt":{"rendered":" Being a programmer, at some point of time we encountered a situation in which you wanted to join (not concat) multiple strings of delimited items in Java. Worst can be if you are provided multiple string literals. Just think for a second and how will you build a string of delimited items using these literals. […]<\/p>\n","protected":false},"author":820,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":10,"footnotes":""},"categories":[1],"tags":[4844,1513,3551],"class_list":["post-35616","post","type-post","status-publish","format-standard","hentry","category-technology","tag-java","tag-java8","tag-string"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t
\nStringJoiner joiner = new StringJoiner(",");
\njoiner.add("java");
\njoiner.add("scala");
\njoiner.add("groovy");
\nString desiredStr = joiner.toString(); \/\/ "java,scala,groovy"<\/p>\n
\n joined = new StringJoiner("-")
\n .add("java")
\n .add("scala")
\n .add("groovy")
\n .toString(); \/\/ "java-scala-groovy"
\n[\/java]<\/p>\n
\nStringJoiner sj = new StringJoiner(":", "[", "]");
\nsj.add("Richard").add("Gilfoyle").add("Erlich");
\nString desiredString = sj.toString();
\n[\/java]<\/p>\n
\n String joined = String.join("\/", "2016", "06", "15" ); \/\/ "2016\/06\/15"
\n[\/java]<\/p>\n
\n List<String> list = Arrays.asList("java", "scala", "groovy");
\n joined = String.join(";", list); \/\/ "java;scala;groovy"
\n[\/java]<\/p>\n
\nList<Employee> list = Arrays.asList(
\n new Employee("Richard", "Hendriks"),
\n new Employee("Erlich", "Bachmann"),
\n new Employee("Jared", "Dunn ")
\n );<\/p>\n
\n .map(Employee::getFirstName)
\n .collect(Collectors.joining(","));<\/p>\n