在我的 iPhone 应用程序中，我需要访问网络服务器才能登录我的系统。客户端要求数据库仅在服务器上。所以我在 ASP.NET 和 MySQL 数据库中创建了一个管理面板，其中存储了登录信息。
现在，当我在代码中使用下面给出的方法从服务器获取数据时，需要花费太多时间（即超过一分钟）来响应。
在我之前从服务器获取特定数据的情况下，当我下次尝试获取它时会快速获取该值。但是对于新数据，它又需要很多时间，或者更确切地说是超时。
有时请求甚至超时。
我应该怎么做才能减少延迟并加快整个登录过程？
有一个更好的方法吗？
有关以下代码的信息：
firstname.text 是我的用户名。
lastname.text 是我的密码。
label.text 是我用来存储从服务器获取的密码的临时标签。
allUsers 是存储从服务器获得的响应的数组。
我也使用 JSON 来解析网络服务器和 iPhone 之间的数据。
我使用 plist 来存储我的网址。Plist名称是url.plist。
代码如下：
SBJSON *json = [SBJSON new];
json.humanReadable = YES;
NSString *service = @"/getUserInfo";
//NSString *requestString = [NSString stringWithFormat:@"{\"method\":\"%@\"}", service];
NSString *requestString = [NSString stringWithFormat:@"{\"firstname\":\"%@\"}",firstName.text,nil];
NSLog(@"Request String: %@", requestString);
NSData *requestData = [NSData dataWithBytes: [requestString UTF8String] length: [requestString length]];
NSString *fileLoc = [[NSBundle mainBundle] pathForResource:@"url" ofType:@"plist" ];
NSDictionary *fileContents = [[NSDictionary alloc] initWithContentsOfFile:fileLoc];
NSString *urlLoc = [fileContents objectForKey:@"baseURL"];
urlLoc = [urlLoc stringByAppendingString:service];
NSLog(@"URL is %@",urlLoc);
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:
[NSURL URLWithString: urlLoc]];
NSString *postLength = [NSString stringWithFormat:@"%d", [requestData length]];
[request setHTTPMethod: @"POST"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody: requestData];
//Data returned by WebService
NSError *respError = nil;
NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: nil error: &respError ];
if (respError) {
NSString *msg = [NSString stringWithFormat:@"Connection failed! Error - %@ %@",
[respError localizedDescription],
[[respError userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]];
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Check your network connection"
message:msg delegate:self cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[alertView show];
NSArray *keys = [NSArray arrayWithObjects:@"firstname", @"lastname", nil];
NSArray *objects = [NSArray arrayWithObjects:@"failed to", @"refresh data...", nil];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];
allUsers = [[NSArray alloc] initWithObjects:dictionary, nil];
//[self setUserData:allUsers];
//[tblView reloadData];
//[allUsers release];
}
else
{
NSString *responseString = [[NSString alloc] initWithData:returnData encoding: NSUTF8StringEncoding];
NSDictionary *results = [responseString JSONValue];
// Additional steps as the webservice is adding an additional "{d:" so stripping of that
NSString *extractUsers = [results objectForKey:@"d"];
// The actual string that Web services returned, so re-scan the same and convert it as object
NSDictionary *finalResult = [extractUsers JSONValue];
allUsers = [finalResult objectForKey:@"users"];
NSLog(@"Data is : %@",allUsers);
NSLog(@"Final Value is : %@",[[allUsers objectAtIndex:0] valueForKey:@"lastname"]);
if([allUsers count]>0)
{
label.text = [[allUsers objectAtIndex:0] valueForKey:@"lastname"];
}
else
{
label.text = @"";
}
[responseString release];
[request release];
}
[inProgressIndicator stopAnimating];
[fileContents release];
//Release all the allocated data
[json release];
}