1、同步请求可以从因特网请求数据,一旦发送同步请求,程序将停止用户交互,直至服务器返回数据完成,才可以进行下一步操作,
2、异步请求不会阻塞主线程,而会建立一个新的线程来操作,用户发出异步请求后,依然可以对UI进行操作,程序可以继续运行
3、GET请求,将参数直接写在访问路径上。操作简单,不过容易被外界看到,安全性不高,地址最多255字节;
4、POST请求,将参数放到body里面。POST请求操作相对复杂,需要将参数和地址分开,不过安全性高,参数放在body里面,不易被捕获。
005 |
NSURL *url = [NSURL URLWithString:@ "http://api.hudong.com/iphonexml.do?type=focus-c" ]; |
011 |
NSURLRequest *request = [[NSURLRequest alloc]initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10]; |
017 |
NSURLRequestUseProtocolCachePolicy(基础策略) |
019 |
NSURLRequestReloadIgnoringLocalCacheData(忽略本地缓存) |
021 |
NSURLRequestReturnCacheDataElseLoad(首先使用缓存,如果没有本地缓存,才从原地址下载) |
023 |
NSURLRequestReturnCacheDataDontLoad(使用本地缓存,从不下载,如果本地没有缓存,则请求失败,此策略多用于离线操作) |
025 |
NSURLRequestReloadIgnoringLocalAndRemoteCacheData(无视任何缓存策略,无论是本地的还是远程的,总是从原地址重新下载) |
027 |
NSURLRequestReloadRevalidatingCacheData(如果本地缓存是有效的则不下载,其他任何情况都从原地址重新下载) |
031 |
NSData *received = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; |
035 |
NSString *str = [[NSString alloc]initWithData:received encoding:NSUTF8StringEncoding]; |
045 |
NSURL *url = [NSURL URLWithString:@ "http://api.hudong.com/iphonexml.do" ]; |
049 |
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10]; |
051 |
[request setHTTPMethod:@ "POST" ]; |
053 |
NSString *str = @ "type=focus-c" ; |
055 |
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding]; |
057 |
[request setHTTPBody:data]; |
063 |
NSData *received = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; |
067 |
NSString *str1 = [[NSString alloc]initWithData:received encoding:NSUTF8StringEncoding]; |
076 |
NSURL *url = [NSURL URLWithString:@ "http://api.hudong.com/iphonexml.do?type=focus-c" ]; |
080 |
NSURLRequest *request = [[NSURLRequest alloc]initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10]; |
084 |
NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self]; |
089 |
NSURL *url = [NSURL URLWithString:@ "http://api.hudong.com/iphonexml.do" ]; |
093 |
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10]; |
095 |
[request setHTTPMethod:@ "POST" ]; |
097 |
NSString *str = @ "type=focus-c" ; |
099 |
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding]; |
101 |
[request setHTTPBody:data]; |
105 |
NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self]; |
111 |
- ( void )connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response |
115 |
NSHTTPURLResponse *res = (NSHTTPURLResponse *)response; |
117 |
NSLog(@ "%@" ,[res allHeaderFields]); |
119 |
self.receiveData = [NSMutableData data]; |
129 |
-( void )connection:(NSURLConnection *)connection didReceiveData:(NSData *)data |
133 |
[self.receiveData appendData:data]; |
139 |
-( void )connectionDidFinishLoading:(NSURLConnection *)connection |
143 |
NSString *receiveStr = [[NSString alloc]initWithData:self.receiveData encoding:NSUTF8StringEncoding]; |
145 |
NSLog(@ "%@" ,receiveStr); |
151 |
-( void )connection:(NSURLConnection *)connection |
153 |
didFailWithError:(NSError *)error |
157 |
NSLog(@ "%@" ,[error localizedDescription]); |