// 添加系统库文件
  CFNetwork.framework
  SystemConfiguration.framework
  MobileCoreServices.framework
  CoreGraphics.framework
  libz.1.1.3.tbd
  libxml2.2.tbd

  // 添加第三方库文件
  ASIHTTPRequest-1.8.2

  // 在 TARGETS -> Builed Settings -> Search Paths -> Header Search Paths 中添加文件路径
  /usr/include/libxml2

  // 在 TARGETS -> Build Phases -> Compile Sources -> ...in .../ASIHTTPRequest 后添加
  -fno-objc-arc

  // 包含头文件
  #import "ASIHTTPRequest.h"
  #import "ASIFormDataRequest.h"

  // 设置请求头
  ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"]];
  [request addRequestHeader:@"Referer" value:@"http://www.dreamingwish.com/"];

  // 设置应用后台运行时是否仍然请求数据
  request.shouldContinueWhenAppEntersBackground = YES;

  // 设置请求超时时重试的次数
  request.numberOfTimesToRetryOnTimeout = 3;

  // 设置 KeepAlive 支持

    // Set the amount of time to hang on to a persistent connection before it should expire to 2 minutes
    request.persistentConnectionTimeoutSeconds = 120;

    // Disable persistent connections entirely
    request.shouldAttemptPersistentConnection = NO;

  // 设置是否显示网络请求信息在 status bar 上
  [ASIHTTPRequest setShouldUpdateNetworkActivityIndicator:NO];

  // 网络状态检查
  BOOL isNetworkInUse = [ASIHTTPRequest isNetworkInUse];

  NSURL *url = [NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

  // 创建请求
  ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

  // 设置超时时间，可不设置，使用默认
  request.timeOutSeconds = 5;

  // 发送同步请求
  [request startSynchronous];

  // 获得错误信息
  NSError *error = [request error];

  // 网络请求失败
  if (error) {

    // 网络请求成功
    NSLog(@"网络请求失败:\n%@", error);

  } else {

    // 获得服务器的响应，字符串格式
    NSString *responseString = [request responseString];
    NSLog(@"网络请求成功:\n%@", responseString);

    // 获得服务器的响应，NSData 格式
    NSData *responseData = [request responseData];
    textView.text = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
  }

  NSURL *url = [NSURL URLWithString:@"http://www.dreamingwish.com/wp-content/uploads/2011/10/asihttprequest-auth.png"];

  ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

  // 设置文件存储路径
  [request setDownloadDestinationPath:@"/Users/JHQ0228/Desktop/asi.png"];

  [request startSynchronous];

  // 获得错误信息
  NSError *error = [request error];

  // 网络请求失败
  if (error) {

    NSLog(@"网络请求失败:\n%@", error);

  } else {

    // 网络请求成功
    NSLog(@"网络请求成功:\n");
  }

  NSURL *url = [NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

  // 创建请求
  ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

  // 设置超时时间，可不设置，使用默认
  request.timeOutSeconds = 5;

  // 设置代理，需遵守 <ASIHTTPRequestDelegate> 协议
  request.delegate = self;

  // 发送异步请求
  [request startAsynchronous];

  // 网络请求成功，协议方法
  - (void)requestFinished:(ASIHTTPRequest *)request {

  }

  // 网络请求失败，协议方法
  - (void)requestFailed:(ASIHTTPRequest *)request {

  }

  NSURL *url = [NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

  // 创建请求，加 __weak 除去 block 循环调用警告
  __weak ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

  // 设置超时时间，可不设置，使用默认
  request.timeOutSeconds = 5;

  // 发送异步请求
  [request startAsynchronous];

  // 网络请求成功
  [request setCompletionBlock:^{

  }];

  // 网络请求失败
  [request setFailedBlock:^{

  }];

  // 通常数据是以 'application/x-www-form-urlencoded' 格式发送的，如果上传了二进制数据或者文件，那么格式将自动变为 ‘multipart/form-data'。

    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://www.dreamingwish.com"]];

    // 没有文件
    [request setPostValue:@"Ben" forKey:@"first_name"];
    [request setPostValue:@"Copsey" forKey:@"last_name"];

    // 发送文件
    [request setFile:@"/Users/ben/Desktop/ben.jpg" forKey:@"photo"];

  // 数据的 mime 头是自动判定的，但是如果你想自定义mime头，那么这样：

    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://www.dreamingwish.com"]];

    // Upload a file on disk
    [request setFile:@"/Users/ben/Desktop/ben.jpg" withFileName:@"myphoto.jpg" andContentType:@"image/jpeg" forKey:@"photo"]; 

    // Upload an NSData instance
    NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"myphoto.jpg"]);
    [request setData:imageData withFileName:@"myphoto.jpg" andContentType:@"image/jpeg" forKey:@"photo"];

  // 你可以使用 addPostValue 方法来发送相同 name 的多个数据：

    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://www.dreamingwish.com"]];

    [request addPostValue:@"Ben" forKey:@"names"];
    [request addPostValue:@"George" forKey:@"names"];

  ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:@"http://www.dreamingwish.com"]];

  [request appendPostData:[@"This is my data" dataUsingEncoding:NSUTF8StringEncoding]];

  // Default becomes POST when you use appendPostData: / appendPostDataFromFile: / setPostBody:
  [request setRequestMethod:@"PUT"];