简介
StringJoiner是java8新增的工具类，StringJoiner是依赖StringBuilder实现，性能和StringBuilder差不多，也是非线程安全的。
示例public static void main(String[] args) { String res1 = String.join("-", "2020","11","11"); System.out.println(res1); //2020-11-11 String res2 = String.join("*", List.of("aa","bb","cc")); System.out.println(res2);//aa*bb*cc List<String> list1= List.of("11","22","33","44"); String res3 = list1.stream() .map(item->item) .collect(Collectors.joining("-")); System.out.println(res3);//11-22-33-44 List<Dept> list2 = List.of(new Dept(10,"ACCOUNTING","NEWYORK"), new Dept(20,"RESEARCH","DALLAS"), new Dept(30,"SALES","CHICAGO")); String res4 = list2.stream().map(item->item.getDname()) .collect(Collectors.joining(", ","{","}")); System.out.println(res4); //{ACCOUNTING, RESEARCH, SALES} StringJoiner sj1 = new StringJoiner(","); sj1.add("zhangsan"); sj1.add("lisi"); sj1.add("wanger"); System.out.println(sj1);// zhangsan,lisi,wanger StringJoiner sj2 = new StringJoiner("/","C:/","/abc.txt").add("aa") .add("bb") .add("cc"); System.out.println(sj2); //C:/aa/bb/cc/abc.txt }
结果：
