?????????????????????????????丶???length???????????????????????????????????????￡?

????Builder.com is awesome!

????Builder.com

?????????????

???????и?????????????洢??StringBuffer???????????????????о???????????

????CharAt??????????е?????????

????SetCharAt???????е????????????????滻??

????GetChars???????????????????????

????Insert??????????λ?ò?????????ж??????汾??????????????????

????Substring???????????????????

????Reverse????StringBuffer???????

???????е??????????????????????????????reverse????????——????????????????????????????????????????????????????????????

????StringBuffer sb=new StringBuffer();
????
????sb.ensureCapacity(100);
????
????sb.append(“Builder.com!”);
????
????System.out.println(sb.toString());
????
????sb.reverse();
????
????Systrm.out.println(sb.toString());

?????????

????Builder.com!

????!moc.redliuB

????StringBuffer??????

?????????????ù???????????ó????????????????????????????????????????????????????Щ????????????????????????????String?????????????????????????????StringBuffer????????????????????????????????????Ч??