String a = “iajfs kajsdfhkasj jhiuhew held at ,Guangzhou, Guangdong,China hkjsdhfakh askdfjas”;java 中想要取得Guangzhou,Guangdong应该用什么方法?sorry, 我没说清楚,Guangzhou,Guangdong这两个单词可能是任意的字符串但格式是这样的“held at Guangzhou,Guangdong,”