http请求的源码

网络编程是iOS开发的重要一环，重要性就不多讲了，下面的代码也比较简单，我在这里也不多解释了。

NSString *url = 。。。//这里打包URL
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:K_IN_TIME_OUT];//K_IN_TIME_OUT是以秒为单位的过期时间，30即可

NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
//NSLog(@"Connect successfully.");
} else {
//NSLog(@"Fail to connect ");
}
[url release];

#pragma mark -
#pragma mark NSURLConnection Delegate Methods
- (void)connection:(NSURLConnection*)connection didReceiveResponse:(NSURLResponse*)response {
NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
int responseStatusCode = [httpResponse statusCode];

....

//请求成功返回，responseStatusCode 是返回代码。
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

//由于http请求的数据是TCP的方式，分段返回的，所以这个函数可能会多次被调用。receivedData 是NSMutableData *
if (nil == receivedData ) {
receivedData = [[NSMutableData alloc]initWithData:data];
}
else {
[receivedData appendData:data];
}
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection{

//请求完成，得到了返回数据在receivedData中。
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
//http请求出错时被调用。
}

注意上面的代码中的内存管理问题。