StringBuilder，StringJoiner，String.join三种不同拼接字符串方法

一、StringBuilder拼接字符串方法

StringBuilder sb=new StringBuilder();
        sb.append("你好");
        sb.append(",");
        sb.append("Ava");
        System.out.println(sb);

二、StringJoiner拼接字符串方法

//以逗号隔开
StringJoiner stringJoiner=new StringJoiner(",");
        stringJoiner.add("zhangsan");
        stringJoiner.add("lisi");
        System.out.println(stringJoiner);

//开头和结尾用[]包起来
        StringJoiner sj1=new StringJoiner(",","[", "]");
        sj1.add("你好");
        sj1.add("张三");
        sj1.add("wfwef");
        System.out.println(sj1);

StringJoiner stringJoiner=new StringJoiner(",");
        stringJoiner.add("zhangsan");//新增
        stringJoiner.add("lisi");
        System.out.println(stringJoiner);
        StringJoiner sj=new StringJoiner(",");
        sj.add("www");
        stringJoiner.merge(sj);//合并在一起
        /*stringJoiner.setEmptyValue(" ");*/ //如果stringJoiner对象为空，设置为“ ”值
        stringJoiner.add("ppp");
        System.out.println(stringJoiner);

三、String.join方法

String st=String.join(",","hello","讲人话");//以逗号隔开拼接
  		System.out.println(st);