java中常见错误

Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}

java中报这种错是因为类型错误，比如强转类型错误，本应该更新数据库却是插入，总之就是你的代码有问题。