在这里阅读时，应该使用NSURLSession进行HTTP工作，它更加灵活和强大.而且我认为注定要替换NSURLconnection ...

As you read here, you should use NSURLSession for HTTP work, it far more flexible and powerful; and I think is destined to replace NSURLconnection...

https://www.objc.io/issues/5-ios7/from-nsurlconnection-to-nsurlsession/

以下是您的示例...

Here is a example for you...

 func getMetaData(lePath:String, completion: (string: String?, error: ErrorType?) -> Void) {
// **** get_metadata ****
    let request = NSMutableURLRequest(URL: NSURL(string: "https://api.dropboxapi.com/2/files/get_metadata")!)
    let session = NSURLSession.sharedSession()
    request.HTTPMethod = "POST"

    request.addValue("Bearer ab-blah-blah", forHTTPHeaderField: "Authorization")
    request.addValue("application/json",forHTTPHeaderField: "Content-Type")
    request.addValue("path", forHTTPHeaderField: lePath)
    let cursor:NSDictionary? = ["path":lePath]
    do {
        let jsonData = try NSJSONSerialization.dataWithJSONObject(cursor!, options: [])
        request.HTTPBody = jsonData
        print("json ",jsonData)
    } catch {
        print("snafoo alert")
    }

    let task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
        if let error = error {
            completion(string: nil, error: error)
            return
        }
        let strData = NSString(data: data!, encoding: NSUTF8StringEncoding)
        print("Body: \(strData)\n\n")
        do {
            let jsonResult = try NSJSONSerialization.JSONObjectWithData(data!, options:NSJSONReadingOptions.MutableContainers);
            self.jsonParser(jsonResult,field2file: "ignore")
            for (key, value) in self.parsedJson {
                print("key2 \(key) value2 \(value)")
            }

            completion(string: "", error: nil)
        } catch {
            completion(string: nil, error: error)
        }
    })
    task.resume()

}