String ==》List
//方法一
List<String> list = Arrays.asList(str.split(","));
//方法二
List<String> list = Arrays.asList(StringUtils.split(str, ","));
List ==》 String
//StringUtils.join(): 参数一:集合 参数二:连接符
String join = StringUtils.join(list, "-");
//String.join()
String str = String.join(",", list);
//遍历list集合存入StringBuilder
StringBuilder sb = new StringBuilder();
for(int i = 0;i < list.size();i++){
sb.append(list.get(i));
}
//流
String str = list.stream().collect(Collectors.joining(","));