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();
    }
}