ios - URLConnection sendSynchronousRequest 问题？

Question

我正在对 Web 服务进行同步调用，有时我会从 Web 服务返回正确的结果，有时我会收到指示运行时错误的 HTML 结果。在 iOS 端我必须做些什么才能正确调用网络服务。这是我的代码:

NSURLResponse *response = nil; 
NSError *error = nil;         
NSString *requestString = @"some parameters!";        
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];

[request addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];        
[request setHTTPMethod:@"POST"];
[request setHTTPBody:[requestString dataUsingEncoding:NSUTF8StringEncoding]];

NSData *data = [NSURLConnection sendSynchronousRequest:request 
                                     returningResponse:&response 
                                                 error:&error];    
NSString *responseData = [[NSString alloc] initWithData:data 
                                               encoding:NSUTF8StringEncoding];

是不是我发布不当？

Answer 1

你必须像这样设置 urlconnection 的委托(delegate)方法

NSMutableURLRequest* urlRequest = [[NSMutableURLRequest alloc] initWithURL:url];
 [urlRequest setHTTPMethod:@"POST"];
 urLConnection=[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];

下面的委托(delegate)方法可以解决问题

    - (void)connection:(NSURLConnection*)connection didReceiveResponse:(NSURLResponse*)response {
    NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
    [receivedData setLength:0];
}

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

    [receivedData appendData:data];

}  

如果连接失败，您将在以下委托(delegate)中收到错误

  - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{}

你最好从已完成的连接中得到响应，它告诉你所有数据都已收到

    - (void)connectionDidFinishLoading:(NSURLConnection *)connection  
{  
recievedData //the complete data 
}