public?class?StringTestdemo?{
????public?static?void?main(String[]?args)?{
????	int?p?=?0;
		//?創建一個空的StringBuilder對象
????	StringBuilder?str=new?StringBuilder();
????	
		
????????
		//?追加字符串
		str.append("jaewkjldfxmopzdm");
		
????????//?從后往前每隔三位插入逗號
		
		for?(int?i?=?0;?i?<?str.length();?i--)?{
			p=str.length()-i;
			
			
		}
		
		StringBuilder?ol=str.insert((str.length()-p),?",");
		System.out.println(ol);
????????
		
????????
????????
		
????????//?將StringBuilder對象轉換為String對象并輸出
		//System.out.print(str.toString());
	}
}