假设您的后端需要一个url编码的表单请求,那么您应该将参数字典转换为url编码的字符串

这是一个例子

let parameters : [String:Any] = ["ajax":1,"test":"abuela"]

var queryItems : [URLQueryItem] = []
for key in parameters.keys {
    if let value = parameters[key] as? String {
        queryItems.append(URLQueryItem(name: key, value: value))
    }else{
        queryItems.append(URLQueryItem(name: key, value: String(describing:parameters[key]!)))
    }
}

var urlComponents = URLComponents()
urlComponents.queryItems = queryItems

那么如果你

print(urlComponents.percentEncodedQuery!)

你会得到

test=abuela&ajax=1

然后,您需要添加 urlString

urlString.append("&" + urlComponents.percentEncodedQuery!)

完整代码

let configuration = URLSessionConfiguration.default;
let session = URLSession(configuration: configuration, delegate: nil, delegateQueue: nil)
var urlString = String()
urlString.append(Constant.BASE_URL)
urlString.append(methodName)

var queryItems : [URLQueryItem] = []
for key in parameters.keys {
    if let value = parameters[key] as? String {
        queryItems.append(URLQueryItem(name: key, value: value))
    }else{
        queryItems.append(URLQueryItem(name: key, value: String(describing:parameters[key]!)))
    }
}

var urlComponents = URLComponents()
urlComponents.queryItems = queryItems

print(urlComponents.percentEncodedQuery!)
urlString.append("&" + urlComponents.percentEncodedQuery!)

let encodedUrl = urlString.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
let serverUrl: URL = URL(string: urlString)!
var request : URLRequest = URLRequest(url: serverUrl, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 60.0)


request.httpMethod = "POST"
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")

let postDataTask : URLSessionDataTask = session.dataTask(with: request, completionHandler:
{
    data, response, error in
    if data != nil && error == nil{
        let res = String(data: data!, encoding: .utf8)
        let dict = convertToDictionary(text: res!)
        if let httpResponse = response as? HTTPURLResponse {
            //print("error \(httpResponse.statusCode)")
            if httpResponse.statusCode == 200
            {
                DispatchQueue.main.async {
                    successBlock (response!,(dict)!)
                }
            }
            else
            {
                if (error?.localizedDescription) != nil
                {
                    errorBlock((error?.localizedDescription)! as String)
                }
                else
                {
                    errorBlock("")
                }
            }
        }
        else
        {
            errorBlock((error?.localizedDescription)! as String)
        }
    }
    else{
        if let httpResponse = error as? HTTPURLResponse {
            //print("error \(httpResponse.statusCode)")
        }
        errorBlock((error?.localizedDescription)! as String)
    }
})
postDataTask.resume()

如果后端正在等待 application/json http正文编码

您正在httpBody中传递JSON对象,但您的contentType标头错误,而不是 "application/x-www-form-urlencoded" "application/json" ,我认为您的json转换是错误的,请尝试直接使用requestDict JSONSerialization 将在有效的JSON对象中转换字典,您可以在 request.httpBody

代替

request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")

通过

request.setValue("application/json", forHTTPHeaderField: "Content-Type")

使用它将requestDict参数字典转换为JSON

request.httpBody = try! JSONSerialization.data(withJSONObject: requestDict)