JSON解析器返回Null

时间:2012-05-14 06:58:05

标签: ios json parsing

我正在尝试学习如何解析JSON数据,以便处理大型数据库。我写了代码登录网站。

我从成功的登录请求中获得了以下JSON数据:

JSON string : correct username and password [{"user_id":"7","first_name":"dada","last_name":"Kara","e_mail":"yaka@gmail","fullname":"Dada Kara","forum_username":"ycan"}]

我使用以下代码进行解析,但它不解析它

-(IBAction)loginButton:(id)sender{

    NSString *username = usernameTextfield.text; 
    NSString *password = passwordTextfield.text;

    NSMutableURLRequest *request =[NSMutableURLRequest requestWithURL:[NSURL URLWithString:kPostUrl]];
    [request setHTTPMethod:@"POST"];

    NSString *post =[[NSString alloc] initWithFormat:@"e_mail=%@&password=%@", username, password];
    [request setHTTPBody:[post dataUsingEncoding:NSASCIIStringEncoding]];

    NSURLResponse *response;
    NSError *err;

    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
    //NSString *responseStr = [NSString stringWithUTF8String:[responseData bytes]];
    //NSLog(@"Response : %@", responseStr);

    NSString *json_string = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    NSLog(@"JSON string : %@", json_string);

    SBJsonParser *parser = [[SBJsonParser alloc] init];
    NSDictionary *responseObj = [parser objectWithString:json_string error:nil];
    NSArray *name = [responseObj objectForKey:@"first_name"];

    NSLog(@"Name : %@", name);
}

我的NSLog名称的结果为NULL

问题在哪里以及我如何解析这样的数据,所以当涉及到很多行时,我可以将它保存到iphone上的本地FMDB数据库

------------------------------ EDIT ------------- --------------------------------------------------

实际问题是来自服务器的响应JSON字符串包含字符串的echo开头,json解析器只在双引号“”之间解析,所以我只需要修剪字符串中的echo并解析新字符串。

和宾果!

//trim in coming echo
    NSString *newString1 = [json_string stringByReplacingOccurrencesOfString:@"correct username and password\n" withString:@""];



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

    NSArray *responseObj = [parser objectWithString:newString1 error:nil];

    NSDictionary *dataDict = [responseObj objectAtIndex:0];

    NSString *userID = [dataDict objectForKey:@"user_id"];

    NSLog(@"user_id: %@", userID);

输出:user_id:7

2 个答案:

答案 0 :(得分:2)

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

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

NSDictionary *dataDict = [responseObj objectAtIndex:0];

NSString *name = [dataDict objectForKey:@"first_name"];

您是否打印过收到的数据?它显示从服务器接收数据?如果是,则尝试使用不同的编码。

答案 1 :(得分:0)

您可以在Mac App Store中使用Objectify(15美元)或JSON加速器(0.99美元)等工具为您自动生成数据模型,使模型像执行object.firstName一样简单。