下面是Swift 3.0中Alamofire 4.0的示例代码

let url = "http://testurl.com"
    let parameters = [
        "email": "asd@fgh.hjk",
        "password": "55555"
    ]
    Alamofire.request(url, method: .post, parameters: parameters, encoding: URLEncoding.default).responseJSON { response in
        switch response.result {
        case .success:
            if let value = response.result.value {
                print(value)
            }
        case .failure(let error):
            print(error)
        }
    }

所以我的解决方案是....你必须在Alamofire中指定参数编码。所以代码看起来像这样。
雨燕2.0

func registerNewUserFormData(completionHandler: (Bool, String?) -> ()){
        // build parameters
        let parameters = ["email": "test@test.cz", "password": "123456"]
        // build request
        Alamofire.request(.POST, urlDomain + "register", parameters: parameters, encoding: .URL).responseJSON { response in
            switch response.result {
            case .Success:
                print("Validation Successful")
                if let JSON = response.result.value {
                    print(JSON)
                }
            case .Failure(let error):
                print(error)
            }
        }
    }

"雨燕5"

let url = "http://testurl.com"
let parameters = [
    "email": "asd@fgh.hjk",
    "password": "55555"
]
AF.request(url, method: .post, parameters: parameters, encoding: URLEncoding.default).responseJSON { response in
    switch response.result {
    case .success:
        if let value = response.result.value {
            print(value)
        }
    case .failure(let error):
        print(error)
    }
}