对php的iPhone请求和响应会降低速度。

Question

我正在使用php文件从mysql到iPhone应用程序中获取数据，以说明我在php中使用此代码的意思。

<?php

$host = "localhost";
$user_name = "user_name";
$password = "password";
$db_name = "db_name";
$con = mysql_connect($host,$user_name,$password)or die (mysql_error());
mysql_select_db($db_name)or die (mysql_error());
mysql_query("set names utf8");

$SQL= "SELECT * FROM emails WHERE 1";

$RS = mysql_query($SQL) or die(mysql_error());
mysql_query("set character_set_server='utf8'");

while($row=mysql_fetch_assoc($RS))
$output[]=$row;

    $json_encode =json_encode($output);
    $utf8_decode = utf8_decode($json_encode);
    echo $json_encode;
    mb_convert_encoding($json_encode, 'UTF-8');
    $html_entity_decode = html_entity_decode($json_encode);

?>

在iPhone中，我使用了以下代码：

NSString *phpUrl = @"url of my php file";

SBJsonParser *parser = [[SBJsonParser alloc] init];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:phpUrl]];

NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

NSString *json_string = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];

NSArray *statuses = [parser objectWithString:json_string error:nil];

for (NSDictionary *status in statuses)
{
    NSString *sEmailID = [status objectForKey:@"ID"];
    NSString *sEmail = [status objectForKey:@"Email"];
    NSString *sPassword = [status objectForKey:@"Password"];
    NSString *sSMTP = [status objectForKey:@"SMTP"];
}

这对我来说很好，我得到了我的数据。我也在我的应用程序中多次使用这种方式。但我的问题是，请求和响应导致我的应用程序的速度降低，并使其工作得如此缓慢。是否有任何方法可以降低请求和响应的速度，或者是否有任何替代方法来代替这一点？提前谢谢。

Answer 1

问题是您正在发送一个同步请求，这将阻塞您的线程，直到请求完成。通常，不建议这样做，这也是因为您无法正确处理错误。您应该改为执行异步请求。如下所示：

NSString *phpUrl = @"url of my php file";

SBJsonParser *parser = [[SBJsonParser alloc] init];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:phpUrl]];

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
    if (error != nil) {
        NSLog(@"%@", error);
        return;
    }

    NSString *json_string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSArray *statuses = [parser objectWithString:json_string error:nil];

    for (NSDictionary *status in statuses)
    {
        NSString *sEmailID = [status objectForKey:@"ID"];
        NSString *sEmail = [status objectForKey:@"Email"];
        NSString *sPassword = [status objectForKey:@"Password"];
        NSString *sSMTP = [status objectForKey:@"SMTP"];
    }
}];

RTM获取更多详细信息。