iOS 多线程编程<十七、NSURLSession的基本用法>

苹果推出NSURLSession是为了代替NSURLConnection

看一下NSURLSession的基本用法：代码如下

<span style="font-size:10px;">//
//  ViewController.m
//  NSURLSession
//
//  Created by fe on 2016/11/7.
//  Copyright © 2016年 fe. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()<NSURLSessionDataDelegate>

@end

@implementation ViewController

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[self sessionDelegate];
}

- (void)get1
{
//1:创建URLSession
NSURLSession *session = [NSURLSession sharedSession];

//2:根据会话对象来创建task
/*
第一个参数：请求对象
第二个参数：data：响应体
response：响应头
error：错误信息
*/
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.baidu.com"]];
NSURLSessionDataTask *dataTask  =  [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
NSLog(@"%@---%@",error,[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil]);

}];

[dataTask resume];
}

- (void)get2
{
//1:创建URLSession
NSURLSession *session = [NSURLSession sharedSession];

//2:根据会话对象来创建task
/*
第一个参数：请求对象
第二个参数：data：响应体
response：响应头
error：错误信息
*/
NSURL *url = [NSURL URLWithString:@"https://www.baidu.com"];
NSURLSessionDataTask *dataTask  =  [session dataTaskWithURL:url completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {

}];

[dataTask resume];
}

- (void)sessionDelegate
{
//1:创建session，并设置代理
/*
第一个参数：配置信息
第三个参数：控制代理方法在哪个线程调用
*/
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:[[NSOperationQueue alloc] init]];
//2:创建task
NSURLSessionTask *dataTask = [session dataTaskWithURL:[NSURL URLWithString:@"https://www.baidu.com"]];
//3:启动
[dataTask resume];
}

#pragma mark - NSURLSessionDataDelegate -
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask
didReceiveResponse:(NSURLResponse *)response
completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler;
{
/*
NSURLSessionResponseCancel = 0   取消（默认）
NSURLSessionResponseAllow = 1    允许接受数据
NSURLSessionResponseBecomeDownload = 2
NSURLSessionResponseBecomeStream
*/
//请求策略，如果不设置请求策略，默认为NSURLSessionResponseCancel，则接收不到数据
completionHandler(NSURLSessionResponseAllow);
}
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask
didReceiveData:(NSData *)data;
{

}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{

}
@end</span>