java字符串'1,2,3,'转换为'1','2','3'

方法一：public class Num {    public static void main(String[] args){           String str1="1,2,3";              String ret="'"+str1.replace(",", "','")+"'";              System.out.println(ret);                }}方法二：public class Num {        public static void main(String[] args){            String str1="1,2,3";            String[] str2=str1.split(",");            String ret="";            for(String i : str2){                     ret+="'"+i+"',";          }         System.out.println(ret);//最后有，         System.out.println(ret.substring(0, ret.length()-1));//最后没有，      }}