iOS网络篇－URLConnection基本使用

知识点

1.HTTP协议的简介（见上节）

2.URLConnection同步请求

3.URLConnection异步请求

4.URLConnection异步请求Block版本

5.URLConnectionPOST请求

6.URLConnection的封装

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2.NSURL，用OC中用来表示URL的类

创建URL：

[NSURL URLWithString:urlStr];

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3.NSURLRequest，用来表示一个请求

//创建Request：
[NSURLRequest requestWithURL:url];
//创建带超时的Request
[NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:0.01f];

//创建可变的Request，可修改Request的属性，如Method等，POST用到
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
request.HTTPMethod = @"POST";

//设置请求体
NSString *paramStr = @"username=qf1508&password=123456";
request.HTTPBody = [paramStr dataUsingEncoding:NSUTF8StringEncoding];

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4.NSURLConnection，表示一个请求响应的连接

//发送同步请求
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

//发送异步请求
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {}];

//发送异步请求，delegate版本
[NSURLConnection connectionWithRequest:request delegate:self];

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4.NSURLConnection的Delegate回调函数

//接收到服务器的响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;

//接收到服务器发送过来的数据，数据是分段发给我们的，所以这个方法会被调用多次
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;

//服务器所有的数据都发送完成之后，会调用这个方法
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;

//请求失败(url不合法、超时、网络中断等等)时会调用这个方法
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;

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:ios9.0不支持http ,推荐https

1接口是https

2修改info.plist

<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>