swiftwebview如何持久化cookie？

问题： swift webview如何持久化cookie？
描述:

swift webview如何持久化cookie？每次干掉app后再此打开app就又要重新网页登录，我只是个后端程序员，求助怎么做才能不需要登录？

代码如下：

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var webview: UIWebView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        let url = URL(string: "http://mysite.com/wap")
        let request = URLRequest(url: url!)
        
        webview.loadRequest(request)
    }

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


}

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解决方案1:

有大神知道吗，求助，别沉下去了。。