sendAsynchronousRequest 过时

- (IBAction)onLoginBtnClick:(UIButton *)sender {
NSLog(@"start to login.");
NSString *loginUrl = [[LSMConstantsUtil hostUrl] stringByAppendingString:[LSMConstantsUtil loginPath]];
NSURL *url = [NSURL URLWithString:loginUrl];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
request.HTTPMethod = @"POST";

UITextField *userNameField = [self.view viewWithTag:10];
NSString *userName = userNameField.text;
UITextField *userPasswordField = [self.view viewWithTag:11];
NSString *userPassword = userPasswordField.text;
NSDictionary *parameterDict = @{
@"userName" : userName,
@"userPassword": userPassword
};
NSData *data = [NSJSONSerialization dataWithJSONObject:parameterDict options:NSJSONWritingPrettyPrinted error:nil];
request.HTTPBody = data;

[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
NSString *sessionIdVar = [[AppDelegate app] sessionId];

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
if (data == nil || connectionError) return;
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
if (dict[@"sessionId"] != nil && ![dict[@"sessionId"]  isEqual: @""]) {
[[AppDelegate app] setSessionId:dict[@"sessionId"]];
}
NSString *state = dict[@"state"];
if ([@"noUser" isEqualToString:state]) {
NSLog(@"Login---noUser");
}
else if ([@"failed" isEqualToString:state]) {
NSLog(@"Login---failed");
}
else if ([@"successful" isEqualToString:state]) {
NSLog(@"Login---successful");
}
NSString *sessionIdVar = [[AppDelegate app] sessionId];
NSLog([@"sessionId:" stringByAppendingString:sessionIdVar]);
}];
}