Java集合类相关常用操作

Java的List可以通过执行String.join()函数将其转化为某个分隔符分隔的字符串，类似Python的’,’.join([1,2,3])

String join API

List<String> strings = new LinkedList<>();
strings.add("Java");strings.add("is");
strings.add("cool");
String message = String.join(" ", strings);
//message returned is: "Java is cool"

Set<String> strings = new LinkedHashSet<>();
strings.add("Java"); strings.add("is");
strings.add("very"); strings.add("cool");
String message = String.join("-", strings);
//message returned is: "Java-is-very-cool"