运用 StringJoiner 高效的拼接字符串

package com.zhong.stringdemo;import java.util.ArrayList;
import java.util.StringJoiner;public class Test {public static void main(String[] args) {ArrayList<String> s = new ArrayList<>();s.add("11");s.add("33");s.add("22");System.out.println(arrayToString1(s));System.out.println(arrayToString2(s));}public static String arrayToString1(ArrayList<String> arr) {if (arr.isEmpty()){return "";}StringBuffer sb = new StringBuffer("[");arr.forEach(x -> sb.append(x).append(", "));sb.deleteCharAt(sb.length() - 1).deleteCharAt(sb.length() -1).append("]");return sb.toString();}public static String arrayToString2(ArrayList<String> arr) {if (arr.isEmpty()){return "";}StringJoiner sj = new StringJoiner(", ", "[", "]");arr.forEach(sj::add);return sj.toString();}
}