iOS 蛇形式(下划线)命名转化为驼峰式

+ (NSString *)convertToCamelCaseFromSnakeCase:(NSString *)key {
    NSMutableString *str = [NSMutableString stringWithString:key];
    while ([str containsString:@"_"]) {
        NSRange range = [str rangeOfString:@"_"];
        if (range.location + 1 < [str length]) {
            char c = [str characterAtIndex:range.location+1];
            [str replaceCharactersInRange:NSMakeRange(range.location, range.length+1) withString:[[NSString stringWithFormat:@"%c",c] uppercaseString]];
        }
    }
    return str;
}