HttpClient.setGlobalCachePolicy(NSURLRequestCachePolicy.UseProtocolCachePolicy) //set the GlobalCachePolicy
//设置全局的缓存策略
  HttpClient.setGlobalNeedSendParametersAsJSON(false) // set need set parameters as json
//设置是否以Json格式发送数据
  HttpClient.setGlobalUsername("yourUserName") //Set the global authentication username
//设置全局的认证用户名
  HttpClient.setGlobalPassword("123456") //Set the global authentication password
//设置全局的认证密码
  HttpClient.setGlobalTimeoutInterval(40) //Set the global Http request time out
//设置全局的请求超期时间
  HttpClient.setGlobalUserAgent("Firefox") // set useragent
//设置全局的UserAgeng

  GlobalCachePolicy//(default value is NSURLRequestCachePolicy.UseProtocolCachePolicy ),
  GlobalCachePolicy//(默认是NSURLRequestCachePolicy.UseProtocolCachePolicy ),
  GlobalNeedSendParametersAsJSON//(the default value is false),
  GlobalNeedSendParametersAsJSON//(默认是 is false),
  GlobalTimeoutInterval//(the default value is 20), 
  GlobalTimeoutInterval//(默认是 is 20), 
  GlobalUserAgent//(the default value is HttpClient)  
  GlobalUserAgent//(默认是 is HttpClient) 

  private init(address:String,method:httpMethod,parameters:Dictionary<String,AnyObject>?, cache:Int,cancelToken:String?,queryPara:Dictionary<String,AnyObject>?, requestOptions:Dictionary<String,AnyObject>?,headerFields:Dictionary<String,AnyObject>?, progress:((progress:Float)->())?,completion:(response:AnyObject?,urlResponse:NSHTTPURLResponse?,error:NSError?)->()){}

  address:String
  // the request address(请求地址，是个String),

  method:httpMethod
  //there is a enum, specifically request method(Http请求方式，是个枚举，参考httpMethod枚举)
  parameters:Dictionary<String,AnyObject>?

  // this is the request parameters, when you use get method.the parameters will be added to the url, and when you use the pose method. all the parameters will be wraped in the http post content (这个就是请求的参数了，是个<String,AnyObject>?的可空字典，如果你使用Get请求方式，这些参数会以key=value的形式添加到Url后面。如果你使用Post请求，所有参数都会放在Http content包里面 )

  cache:Int
  //if you need cache this url, you can set the cache time bigger than 0. it any work at Get method, in post method this feature can not work (这个是设置缓存，单位是秒。如果设置的数字大于0，那么这个Url的get请求会被缓存起来，时间是你设置的秒数，参数小于 等于0无效。Post请求这个参数也无效 )

  cancelToken:String?
  //this is the cancel token, if you want cancel this request, just call the static funtion HttpClient.cancelRequestWithIndentity(token:string)
(这个是取消的Token，这个字符串，如果你想取消请求，只要调用这个HttpClient.cancelRequestWithIndentity(token:string)函数就行 )

  queryPara:Dictionary<String,AnyObject>?
  // this parameter is special.  you can use it on this condition. when you use post method but also want to add some parameters to the url, then use this parameter(和parameters有点一不样，queryPara比较特别。它也是个可空的<String,AnyObject>字典，它只适合于这种场景：如果你使用Post请求，但是你也想在Url里面添加些key=value的参数，就使用这个参数 )

  requestOptions:Dictionary<String,AnyObject>?
  // this parameter let you personalization this request.make it not obey the global config. for instance, if you need set this request timeout . you need add timeout in the dictionary. and pass it to the request.
(requestOptions参数是你用来个性化请求用的，也是个它也是个可空的<String,AnyObject>字典。来使它不遵循全局的Http设置。比如说，你想设置该次请求的超期时间，那么你将超期时间加到字典里，再加上这个参数即可 )

  headerFields:Dictionary<String,AnyObject>?
  // the paramter is to set the Http request header. ( headerFields也是个可空的<String,AnyObject>字典，用来设置Http请求头)

  progress:((progress:Float)->())?
  // this is the upload&download progress ( progress是一个可空的block,是用来监视上传&下载进程)

  completion:(response:AnyObject?,urlResponse:NSHTTPURLResponse?,error:NSError?)->())
  // this is the completion call-back handler, response is a NSdata object, and you can fetch Http response info from urlResponse if error occur, the response will be nil and you can fetch the error info from error object ( completion 是一个可空的请求完成后的回调block, response实际是一个NSData对象，可以从urlResponse里获取Http response 的相关信息。如果有错误发生，那么error不为nil且response为nil，可以从error里面获取该次请求的错误，)

  public static func get(address:String,parameters:Dictionary<String,AnyObject>?,cache:Int,cancelToken:String?, queryPara:Dictionary<String,AnyObject>?, completion:(response:AnyObject?,urlResponse:NSHTTPURLResponse?,error:NSError?)->())
// this is the primary get static fun，It can complete the simple basic get request.
// 这是最主要的Get静态函数，可以完成最简单基本的get请求。

  HttpClient.get("http://www.baidu.com", parameters: nil, cache: 20, cancelToken: nil, completion: { (response, urlResponse, error) -> () in
                if error != nil{ 
                    println("there is a error\(error)")
                    return
                } // if error is not nil,then mean some error occur during the http request process,you must handle it.
                //如果error不是nil，说明http请求过程了发生了一些错误。你必须处理它。
                if let data = response as? NSData{
                    if let result = NSString(data: data, encoding: NSUTF8StringEncoding){
                      println(result)
                    }
                }
                //if error is nil, then handle the response.
                //没有错误，再直接处理reponse就行
            })

  First: check the error parameter, if error is not nil, handle the error and display the correct message to the user
第一步：检查error参数，如果error不是nil，处理这个错误再正确地向用户展示信息。
  Second: convert the response to the NSData, accord the request result, it can be a Image NSData , Text NSData or JSON.
第二步：将response转换成NSData，根据请求结果，它可能是Image的NSData，Text NSData或者JSON
  Third: convert the NSData to the Model or Object and use it
第三步，将NSData转换成Model或者JSON

let path: AnyObject? = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true).first
let myPath = (path as! NSString).stringByAppendingPathComponent("img.jpg")
let httpOption = [HttpClientOption.SavePath:myPath,HttpClientOption.TimeOut:NSNumber(int: 100)]
// comstmize the Http request 个性化Http请求
let para = ["a":"123"]
HttpClientManager.Get("http://img1.gamersky.com/image2015/09/20150912ge_10/gamersky_45origin_89_201591217486B7.jpg").addParams(para).cache(100).requestOptions(httpOption).progress({ (progress) -> () in
                print(progress)
            }).completion({ (response, urlResponse, error) -> () in
                if error != nil{
                    print("there is a error\(error)")
                    return
                }
                if let data = response as? NSData{
                    if let result = UIImage(data: data){
                        let tvc = ImgViewController()
                        tvc.img = result
                        self.navigationController?.pushViewController(tvc, animated: true)
                    }
                }

            })
//Unlike commom static function, use HttpClientManager functional programming style is more friendly, you do not need set unnecessary parameters to nil.just use . grammar. but if you use Objectice-C, more 【】 will mill make more improper
//不像普通的静态函数，使用HttpClientManager的函数式风格编程更友好，你不需要将不需要的参数再设置成nil了。只要用.语法就可以了，不过如果你使用Objective-C的话，太多的【】可能会看起来比较乱

cache: 20,

HttpClient.clearUrlCache("www.baidu.com") //if you can clear one specific cache, just pass the cache url
//如果你想根据Url来清空缓存，只要传Cache的url就行
HttpClient.clearCache() //call  clearCache（） clear all the url cache
//调用 clearCache（）来清空全部缓存

cancelToken: "cancel", //set the cancel token 设定取消的Token
HttpClient.cancelRequestWithIndentity("cancel")  //use cancel token to cancel 传入Token来取消请求
HttpClient.cancelAllRequests() //cancel all the request 取消所有请求

let myPath = "path" //declare a path, 声明一个路径
let httpOption = [HttpClientOption.SavePath:myPath,HttpClientOption.TimeOut:NSNumber(int: 100)] //declare Http request option 个性化Http请求字典