网络请求

网络请求

• 网络监测

  1.根据主机名判断网络是否连接

  2.注册网络监听通知

  3.开启监听

网络监测代码

    #import "ViewController.h"
    #import "Reachability.h"
    
    @interface ViewController ()
    
    @property (nonatomic, strong) Reachability * reach;
    
    @end
    
    @implementation ViewController
    
    - (void)viewDidLoad {
       [super viewDidLoad];
       // Do any additional setup after loading the view, typically from a nib.
       
       //根据主机名判断网络是否连接
       self.reach = [Reachability reachabilityWithHostName:@"www.baidu.com"];
       
       //注册网络监听通知
       [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged) name:kReachabilityChangedNotification object:nil];
       
       //开启监听
       [self.reach startNotifier];
    }
    
    - (void)reachabilityChanged {
       
       switch (self.reach.currentReachabilityStatus) {
           case NotReachable:
               NSLog(@"没有网络");
               break;
           case ReachableViaWiFi:
               NSLog(@"WiFi网络");
               break;
           case ReachableViaWWAN:
               NSLog(@"移动蜂窝网");
               break;
           default:
               NSLog(@"未知网络");
               break;
       }
    }
    
    - (void)dealloc {
       
       //把当前的对象所有通知删除
       [[NSNotificationCenter defaultCenter] removeObserver:self];
    
       //停止监听
       [self.reach stopNotifier];
    }
    
    - (void)didReceiveMemoryWarning {
       [super didReceiveMemoryWarning];
       // Dispose of any resources that can be recreated.
  }

@end

网络请求

• 1.建URL，访问网络资源的唯一地址

• 2.创建网络请求

• 3.建立连接

代码

#import "ViewController.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIWebView *webView;

@end

@implementation ViewController

- (void)viewDidLoad {
   [super viewDidLoad];
   // Do any additional setup after loading the view, typically from a nib.
   
   
   //1、创建URL，访问网络资源的唯一地址
   
   NSURL * url = [NSURL URLWithString:@"http://192.168.1.123/demo.json"];
   
   //2、创建网络请求
   
   /*
    cachePolicy 缓存策略
    
    NSURLRequestUseProtocolCachePolicy = 0, //自动缓存策略
    
    NSURLRequestReloadIgnoringLocalCacheData = 1, //每次都请求网络，无论本地是否存在缓存
    
    NSURLRequestReturnCacheDataElseLoad = 2,//如果有缓存返回缓存，没有就加载网络
    NSURLRequestReturnCacheDataDontLoad = 3,//如果有缓存返回缓存，没有也不加载网络
    
    timeoutInterval 请求超时 默认超时时间是60 一般设置 10 - 20s
    
    */
   
   
//    NSURLRequest * request = [NSURLRequest requestWithURL:url];
   
   NSURLRequest * request = [NSURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:15];
   
   //3、建立连接
   
   //sendAsynchronousRequest 建立异步网络连接
   //queue  可以传主队列，或全局队列
   
   //[NSOperationQueue mainQueue]   不用调到主队列直接更新
   
   //[[NSOperationQueue alloc] init]  则需要调回主线程更新UI
   
   [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
       //response 服务器响应信息，一般下载时有用
       //data  服务器返回的数据
       //connectionError 网络请求错误
       
       //服务器与客户端是以二进制流通讯的
       
//        NSLog(@"%@",data);
//        
//        [data writeToFile:@"/Users/dahuan/Desktop/test" atomically:YES];
       
       NSLog(@"%@",[NSThread currentThread]);
       
//        if (connectionError) {
//            
//            NSLog(@"错误信息：%@",connectionError);
//            
//        } else {
//            
//            NSLog(@"响应信息：%@",response);
//            
//            NSString * string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//            
//            NSLog(@"%@",string);
//            
//            [self.webView loadHTMLString:string baseURL:nil];
//        }
//
//        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
//            //更新UI
//        }];
  
       
   }];
   
   
}

- (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
   // Dispose of any resources that can be recreated.
}

@end

同步网络请求

    #import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    NSURL * url = [NSURL URLWithString:@"http://192.168.1.123/demo.json"];
    
    NSURLRequest * request = [NSURLRequest requestWithURL:url];
    
    //同步网络请求
    
    NSURLResponse * response = nil;
    NSError * error = nil;
    
    NSData * data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
    
    NSString * string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"%@",string);
    
    NSLog(@"%@",response);
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end