java string \u600e\u6837\u622a\u53d6\u524dn\u4e2a\u5b57\u7b26\uff1f\u7684\u89e3\u51b3\u65b9\u6848\u5217\u8868

\u672c\u89c6\u9891\u8bb2\u89e3\u7684\u662fJava\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\u8bed\u8a00\u4e2d\u5173\u4e8eStringBuffer\u7684\u77e5\u8bc6\uff0c\u91cd\u70b9\u8bb2\u89e3\u4e86substring\u65b9\u6cd5\u622a\u53d6\u5b57\u7b26\u4e32\u53ca\u6ce8\u610f\u70b9\uff0c\u9700\u8981\u6ce8\u610f\u7684\u662f\u4e00\u4e2a\u8303\u56f4\u662f\u534a\u95ed\u534a\u5f00\u533a\u95f4\u3002

\u901a\u8fc7charAt\u65b9\u5f0f\u83b7\u53d6\u7b2c\u4e00\u4e2a\u5b57\u7b26
\u4f8b\u5982\uff1a
String str = "adadsauo";//\u5b9a\u4e49\u4e00\u4e2a\u5b57\u7b26\u4e32char fir = str.charAt(0);//\u83b7\u53d6\u5b57\u7b26\u4e32\u7684\u7b2c\u4e00\u4e2a\u5b57\u7b26charAt(int index)\u65b9\u6cd5\uff0c\u8fd4\u56de\u5b57\u7b26\u4e32\u6307\u5b9a\u7d22\u5f15\u4f4d\u7f6e\u7684char\u503c\u3002\u7d22\u5f15\u8303\u56f4\u4e3a0~length()-1