1、网络监测
//根据主机名判断网络是否连接
Reachability *reach = [Reachability reachabilityWithHostName:@"www.baidu.com"];
self.reach = reach;
//注册网络监听通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged) name:kReachabilityChangedNotification object:nil];
//开启监听
[reach startNotifier];
//根据currentReachabilityStatus判断网络状态
NotReachable = 0, //没有网络
ReachableViaWiFi = 2, //不用花钱WIFI
ReachableViaWWAN = 1 //2G,3G,4G
- (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];
}
2、异步网络请求
//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 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
}];
}];
3、同步网络请求
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);
4、NSURLConnection代理方法
self.data = [NSMutableData data];
NSString * urlString = @"http://192.168.1.123/把悲伤留给自己.mp3";
//NSString 中包含中文字符时转换为NSURL
urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL * url = [NSURL URLWithString:urlString];
NSURLRequest * request = [NSURLRequest requestWithURL:url];
NSURLConnection * connect = [NSURLConnection connectionWithRequest:request delegate:self];
//开启网络连接
[connect start];
//服务器返回响应信息1
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
NSLog(@"%@",response);
}
//接受数据（多次调用）2
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.data appendData:data];
NSLog(@"%@",data);
}
//请求完成3
- (void)connectionDidFinishLoading:(NSURLConnection *)connection{
[self.data writeToFile:@"/Users/dahuan/Desktop/aaaaa.mp3" atomically:YES];
NSLog(@"网络请求完成");
}