1 GET請求

1,確定URL

NSURL *url = [NSURL URLWithString:@"xxx"];

2,創(chuàng)建請求對象

NSURLRequest *request = [NSURLRequest requestWithURL:url];

3,獲得一個會話對象

NSURLSession *session = [NSURLSession sharedSession];

4.創(chuàng)建請求任務

//第一個參數(shù):請求對象
//第二個參數(shù):completionHandler 完成后執(zhí)行的回調(diào)
            //data:響應體
            //response:響應頭
            //error:錯誤信息
//!!!注意:默認情況下completionHandler在子線程中調(diào)用
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:
^(NSData * _Nullable data, NSURLResponse * _Nullable response,
 NSError * _Nullable error) {
//解析服務器返回的數(shù)據(jù)
}];

5,執(zhí)行任務

[dataTask resume];

2 POST請求

1,確定URL

NSURL *url = [NSURL URLWithString:@"xxx"];

2,創(chuàng)建可變請求對象

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
//修改請求方式為POST
request.HTTPMethod = @"POST"; 
//設置請求體
request.HTTPBody = [@"username=520it&pwd=520&type=JSON" dataUsingEncoding:NSUTF8StringEncoding]; 

3,獲得一個會話對象

NSURLSession *session = [NSURLSession sharedSession];

4.創(chuàng)建請求任務

NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:
^(NSData * _Nullable data, NSURLResponse * _Nullable response, 
NSError * _Nullable error) {
//解析服務器返回的數(shù)據(jù)
}];

5,執(zhí)行任務

[dataTask resume];

3 代理方法

1,確認請求路徑

NSURL *url = [NSURL URLWithString:@"xxx"];

2,創(chuàng)建會話對象

NSURLSession *session = [NSURLSession sessionWithConfiguration:
[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[NSOperationQueue mainQueue]];

3,創(chuàng)建任務Task

NSURLSessionDataTask *dataTask =  [session dataTaskWithURL:url];

4,執(zhí)行Task

[dataTask resume];

5,-----代理-----

//當接收到服務器響應的時候調(diào)用
//默認情況下是不會接收服務器返回數(shù)據(jù)的,如果需要接收應該主動告訴系統(tǒng)
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask 
didReceiveResponse:(NSURLResponse *)response 
completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    NSLog(@"didReceiveResponse");
    /*
     NSURLSessionResponseCancel = 0,     取消(默認的做法)
    NSURLSessionResponseAllow = 1,      允許(接收數(shù)據(jù))
    NSURLSessionResponseBecomeDownload = 2,
    NSURLSessionResponseBecomeStream NS_ENUM_AVAILABLE(10_11, 9_0) = 3,
     */
    completionHandler(NSURLSessionResponseAllow);
}

//當接收到服務器返回數(shù)據(jù)的時候調(diào)用(會調(diào)用多次)
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask 
didReceiveData:(NSData *)data
{
    NSLog(@"didReceiveData");
    [self.resultData appendData:data];
}

//當請求完成或者是失敗的時候調(diào)用
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task 
didCompleteWithError:(NSError *)error
{
     NSLog(@"didCompleteWithError");
    
    //解析數(shù)據(jù)
    NSLog(@"%@",[[NSString alloc]initWithData:self.resultData encoding:NSUTF8StringEncoding]);
}