XCode中异步调用 WebService获得大数据量的处理方式

调用 webserivce的方法

//异步请求  
NSURLConnection *theConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];  
if (theConnection) {     
    // Create the NSMutableData that will hold   
    // the received data   
    // receivedData is declared as a method instance elsewhere   
    self.receivedData=[[NSMutableData data] retain];     
} else {     
      
} 

其中 receivedData 是定义在 .h 文件中的 NSMutalbeData 类型

要实现4个方法 ，分别在 调用时候，发生错误，获得数据，调用完成的时候触发

//如果调用有错误，则出现此信息  
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error  
{  
    DLog(@"ERROR with theConenction:%@",error );  
   
}  
  
//开始调用请求  
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {  
    // store data  
    DLog(@"didReceiveResponse");  
    [self.receivedData setLength:0  ];            //通常在这里先清空接受数据的缓存  
}  
  
//调用成功(大数据量的时候可能会多次调用)，获得soap信息  
-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *)responseData  
{  
    DLog(@"（在大数据量的时候，可能是一部分）获取的返回responseData 是:%@",[[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] autorelease]);  
    [self.receivedData appendData:responseData];      
}  
  
- (void) connectionDidFinishLoading:(NSURLConnection *) connection  
{  
    DLog(@"%d",[self.receivedData length]);  
    NSString * wsReturnValueString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];  
    DLog(@"webserivce 调用结束，收取到的 全部报文是:%@",wsReturnValueString );  
    DLog(@"WebService数据接受完成");  
}