1 GET請(qǐng)求

1,確定URL

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

2,創(chuàng)建請(qǐng)求對(duì)象

NSURLRequest *request = [NSURLRequest requestWithURL:url];

3,獲得一個(gè)會(huì)話(huà)對(duì)象

NSURLSession *session = [NSURLSession sharedSession];

4.創(chuàng)建請(qǐng)求任務(wù)

//第一個(gè)參數(shù):請(qǐng)求對(duì)象
//第二個(gè)參數(shù):completionHandler 完成后執(zhí)行的回調(diào)
            //data:響應(yīng)體
            //response:響應(yīng)頭
            //error:錯(cuò)誤信息
//!!!注意:默認(rèn)情況下completionHandler在子線(xiàn)程中調(diào)用
NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:
^(NSData * _Nullable data, NSURLResponse * _Nullable response,
 NSError * _Nullable error) {
//解析服務(wù)器返回的數(shù)據(jù)
}];

5,執(zhí)行任務(wù)

[dataTask resume];

2 POST請(qǐng)求

1,確定URL

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

2,創(chuàng)建可變請(qǐng)求對(duì)象

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

3,獲得一個(gè)會(huì)話(huà)對(duì)象

NSURLSession *session = [NSURLSession sharedSession];

4.創(chuàng)建請(qǐng)求任務(wù)

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

5,執(zhí)行任務(wù)

[dataTask resume];

3 代理方法

1,確認(rèn)請(qǐng)求路徑

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

2,創(chuàng)建會(huì)話(huà)對(duì)象

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

3,創(chuàng)建任務(wù)Task

NSURLSessionDataTask *dataTask =  [session dataTaskWithURL:url];

4,執(zhí)行Task

[dataTask resume];

5,-----代理-----

//當(dāng)接收到服務(wù)器響應(yīng)的時(shí)候調(diào)用
//默認(rèn)情況下是不會(huì)接收服務(wù)器返回?cái)?shù)據(jù)的,如果需要接收應(yīng)該主動(dòng)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(rèn)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(dāng)接收到服務(wù)器返回?cái)?shù)據(jù)的時(shí)候調(diào)用(會(huì)調(diào)用多次)
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask 
didReceiveData:(NSData *)data
{
    NSLog(@"didReceiveData");
    [self.resultData appendData:data];
}

//當(dāng)請(qǐng)求完成或者是失敗的時(shí)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]);
}