AlamofireでShiftJISのサーバにデータを送信する

ViewController.swift

import UIKit
import Alamofire

class ViewController: UIViewController {

    @IBOutlet weak var viewLabel: UILabel!
    
    @IBOutlet weak var sendBtn: UIButton!
    
    @IBOutlet weak var inputTxt: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view, typically from a nib.
        NotificationCenter.default.addObserver(self, selector: #selector(ViewController.didForeground), name: NSNotification.Name.UIApplicationWillEnterForeground, object: nil)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @objc func didForeground() {
        if (self.isViewLoaded && self.view.window != nil) {
            print("foreground show")
            viewLabel?.text = "foreground"
        }
    }
    @IBAction func didTouchDown(_ sender: UIButton) {
        do {
        let param : Parameters = ["userInfo": "あああああ"]
        let header : HTTPHeaders = ["Content-Type": "application/x-www-form-urlencoded; charset=shift_JIS"]
        let url = URL(string: "http://foo.local:8080/struts-sample/alamofire.action")
            var request = URLRequest(url: url!)
            request.httpMethod = "POST"
            request.setValue("application/x-www-form-urlencoded; charset=shift_JIS", forHTTPHeaderField: "Content-Type")
            let encodedRequest = try URLEncoding.queryString.encode(request, with: param)
            Alamofire.request(encodedRequest).responseJSON(completionHandler: {response in
                print("---------------------------------------------------------")
                print("response: \(String(describing: response.result.value))")
                do {
                    let json = try JSONSerialization.jsonObject(with: response.data!, options: .allowFragments)
                    let top = json as! NSDictionary
                    print(top["message"]!)
                } catch {
                    print("error")
                }
                print("---------------------------------------------------------")
            })
        
            // こっちは失敗
        Alamofire.request("http://foo.local:8080/struts-sample/alamofire.action", method: .post, parameters: param, headers: header).responseJSON(completionHandler: {response in
            print("response: \(String(describing: response.result.value))")
            do {
                let json = try JSONSerialization.jsonObject(with: response.data!, options: .allowFragments)
                let top = json as! NSDictionary
                print(top["message"]!)
            } catch {
                print("error")
            }
            print("sample: あああああ")
        })
        } catch {
            print("ERROR")
        }
    }
}