Java新特性玩转JDK8之joining函数 - 超级大汇总——DBC的博客超级大汇总—

拼接函数 Collectors.joining

//3种重载⽅法
Collectors.joining()
Collectors.joining("param")
Collectors.joining("param1", "param2", "param3")

其中⼀个的实现

 public static Collector<CharSequence, ?, String> joining() {
 return new CollectorImpl<CharSequence, StringBuilder, String>(
 StringBuilder::new, StringBuilder::append,
 (r1, r2) -> { r1.append(r2); return r1; },
 StringBuilder::toString, CH_NOID);
 }

说明：

该⽅法可以将Stream得到⼀个字符串， joining函数接受三个参数，分别表示元素之间的连
接符、前缀和后缀。

String result = Stream.of("springboot", "mysql", "html5",
"css3").collect(Collectors.joining(",", "[", "]"));

小例子

        List<String> list = Arrays.asList("springboot教程","springcloud教程","java教程","架构教程");
        String result1 = list.stream().collect(Collectors.joining());
        System.out.println(result1);

        String result2 = list.stream().collect(Collectors.joining("||"));
        System.out.println(result2);

        String result3 = list.stream().collect(Collectors.joining("||","[","]"));
        System.out.println(result3);


        String result = Stream.of("springboot","mysql","html5","css3").collect(Collectors.joining(",","[","]"));
        System.out.println(result);

控制台输出

本文作者为DBC，转载请注明。