网络请求

网络请求

• 网络监测

  1.根据主机名判断网络是否连接

  2.注册网络监听通知

  3.开启监听

网络监测代码

import "ViewController.h"

import "Reachability.h"

@interface ViewController ()

@property (nonatomic, strong) Reachability * reach;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

//根据主机名判断网络是否连接
self.reach = [Reachability reachabilityWithHostName:@"www.baidu.com"];

//注册网络监听通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged) name:kReachabilityChangedNotification object:nil];

//开启监听
[self.reach startNotifier];
}

- (void)reachabilityChanged {

switch (self.reach.currentReachabilityStatus) {
case NotReachable:
NSLog(@"没有网络");
break;
case ReachableViaWiFi:
NSLog(@"WiFi网络");
break;
case ReachableViaWWAN:
NSLog(@"移动蜂窝网");
break;
default:
NSLog(@"未知网络");
break;
}
}

- (void)dealloc {

//把当前的对象所有通知删除
[[NSNotificationCenter defaultCenter] removeObserver:self];

//停止监听
[self.reach stopNotifier];
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end

网络请求

• 1.建URL，访问网络资源的唯一地址

• 2.创建网络请求

• 3.建立连接

代码

import "ViewController.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIWebView *webView;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

//1、创建URL，访问网络资源的唯一地址

NSURL * url = [NSURL URLWithString:@"http://192.168.1.123/demo.json"];

//2、创建网络请求

/*
cachePolicy 缓存策略

NSURLRequestUseProtocolCachePolicy = 0, //自动缓存策略

NSURLRequestReloadIgnoringLocalCacheData = 1, //每次都请求网络，无论本地是否存在缓存

NSURLRequestReturnCacheDataElseLoad = 2,//如果有缓存返回缓存，没有就加载网络
NSURLRequestReturnCacheDataDontLoad = 3,//如果有缓存返回缓存，没有也不加载网络

timeoutInterval 请求超时 默认超时时间是60 一般设置 10 - 20s

*/

// NSURLRequest * request = [NSURLRequest requestWithURL:url];

NSURLRequest * request = [NSURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:15];

//3、建立连接

//sendAsynchronousRequest 建立异步网络连接
//queue 可以传主队列，或全局队列

//[NSOperationQueue mainQueue] 不用调到主队列直接更新

//[[NSOperationQueue alloc] init] 则需要调回主线程更新UI

[NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {
//response 服务器响应信息，一般下载时有用
//data 服务器返回的数据
//connectionError 网络请求错误

//服务器与客户端是以二进制流通讯的

// NSLog(@"%@",data);
//
// [data writeToFile:@"/Users/dahuan/Desktop/test" atomically:YES];

NSLog(@"%@",[NSThread currentThread]);

// if (connectionError) {
//
// NSLog(@"错误信息：%@",connectionError);
//
// } else {
//
// NSLog(@"响应信息：%@",response);
//
// NSString * string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//
// NSLog(@"%@",string);
//
// [self.webView loadHTMLString:string baseURL:nil];
// }
//
// [[NSOperationQueue mainQueue] addOperationWithBlock:^{
// //更新UI
// }];

}];

}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end

同步网络请求

import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSURL * url = [NSURL URLWithString:@"http://192.168.1.123/demo.json"];

NSURLRequest * request = [NSURLRequest requestWithURL:url];

//同步网络请求

NSURLResponse * response = nil;
NSError * error = nil;

NSData * data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

NSString * string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

NSLog(@"%@",string);

NSLog(@"%@",response);

}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end