登陆

1.得到session对象

 NSURLSession *session = [NSURLSession sharedSession];

2.任务请求都是一个任务

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

 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

 request.HTTPMethod = @"POST";

 request.HTTPBody = [@"username=lihuan&pwd=pp" dataUsingEncoding:NSUTF8StringEncoding];

 NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

取出登陆之后的数据

 }];

 [task resume];