• 1.同步請求，一旦發(fā)送請求，程序禁止用戶交互，直到服務(wù)器返回?cái)?shù)據(jù)完成，才能進(jìn)行下一步操作
  • 2.異步請求不會阻塞主線程，而回建立一個新的線程來操作，用戶發(fā)出請求以后，可以繼續(xù)對UI操作，程序可以繼續(xù)運(yùn)行
  • 3.GET請求，將參數(shù)直接寫在訪問路徑上。操作簡單，但是容易被外界看到，安全性不高。
  • 4.POST請求，將參數(shù)放到body里面，POST操作相對復(fù)雜，需要將參數(shù)和地址分開，相對更加安全.

GET請求

    NSString *urlString = KgetUrl;
    NSURL *url = [NSURL URLWithString:urlString];
    //創(chuàng)建請求體
    NSURLRequest *request = [NSURLRequest  requestWithURL:url];
    
    //創(chuàng)建一個session對象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //創(chuàng)建請求任務(wù)
    NSURLSessionTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        
        NSString *result = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        
        NSLog(@"GTE:%@",result);
    }];
    //注意不能忘了這一步
    [task resume];

POST請求

 NSString *urlString = KpostUrl;
    NSURL *url = [NSURL URLWithString:urlString];
    //創(chuàng)建請求體，注意是 NSMutableURLRequest
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    //設(shè)置為POST請求
    [request setHTTPMethod:@"POST"];
    
    NSString *postString = KparameterUrl;
    
    NSData *data = [postString dataUsingEncoding:NSUTF8StringEncoding];
    //添加參數(shù)
    [request setHTTPBody:data];
    
    //創(chuàng)建session對象
    NSURLSession *session = [NSURLSession sharedSession];
    
    //創(chuàng)建一個請求任務(wù)
    NSURLSessionTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSString *result = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"POST%@",result);
    }];
    
    [task resume];

代理

- (IBAction)delegateAction:(UIButton *)sender {
    
    //遵循代理 <NSURLSessionDataDelegate>
         //
    NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];
    //新建任務(wù)
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:KgetUrl] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10];
    //創(chuàng)建請求
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request];
    
    [task resume];
    
}

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler{
    
    //當(dāng)網(wǎng)絡(luò)基于HTTP協(xié)議時,response是NSHTTPURLResponse類型的
//    NSHTTPURLResponse *URLResponse = (NSHTTPURLResponse *)response;
//    long long length = URLResponse.expectedContentLength;
//    NSLog(@"%ld",URLResponse.statusCode);
//    NSLog(@"%lld",length);
    
    //允許服務(wù)器回傳數(shù)據(jù)
    completionHandler(NSURLSessionResponseAllow);
}

//接受服務(wù)器傳回來的數(shù)據(jù)，可能執(zhí)行多次
-  (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data{
    
 
    NSString *string=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
    if (string) {
        [self.astring appendString:string];

    }
        NSLog(@"%@",self.astring);


}

//接受或者失敗時調(diào)用
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error{
    NSLog(@"%@******",error);
    
}

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