public class HelloWorld {
??? public static void main(String[] args) {
??// 創(chuàng)建一個(gè)空的StringBuilder對(duì)象
??StringBuilder str=new StringBuilder();
???????
??// 追加字符串
??str.append("jaewkjldfxmopzdm");
??
??????? // 從后往前每隔三位插入逗號(hào)
??for(int i=str.length();i>0;i=i-3){
????? str.insert(i,",");
??}
??????? // 將StringBuilder對(duì)象轉(zhuǎn)換為String對(duì)象并輸出
??System.out.print(str.toString());
?}
}