String.join

https://docs.oracle.com/javase/8/docs/api/ http://www.matools.com/api/java8 1 使用场景 String集合快速转化为指定分隔符分割的字符串;最后一个元素后面无分隔符; 1.1 java8前 @Test public void test() { //分隔符 final String SEPARATOR = ","; List cities = Arrays.asList("Milan", "London", "New York", "San Francisco"); StringB