我正在尝试解析并通过类似于此的HTTP响应获取给我的输出，并且在一个名为'line'的字符串中。 （每次运行时响应内容都会改变）
{"needle":"opuwyxib"," haystack":["igrnevcp","ripfxjuv","amjctpsr","ucdpotrj","usqhrmvz","jblhmqgx","opuwyxib","mbhfylwt","ltkvhjsw","dhnpaurg","muyesbcg","etxmvzyd","chyfigmd","udskerov","ngoqzmve","ukeljaqw","dngqmtrz","xztpbjfs","zgdrcnbp","tkfivrld"]}
如何使用Gson提取它然后使用提取来找到针的索引？