如何向服务器发出Json请求？

Question

我正在做一个应该与服务器一起工作的应用程序。

需要通过程序使用用户名和密码在服务器上进行授权。 我需要使用以下行向服务器发出请求：

{"login": "mad_fashist", "password": "eqeeuq313371", "method": "authentificator"}

该字符串必须位于杰森。

作为响应，如果身份验证失败，我应该得到一行：

{"validated": "false", "kuid": "", "sid": "", "uid": ""}

并且如果认证通过：

{"validated":"true","kuid":"6","sid":"834fe9b4626502bf9ff23485a408ac40","uid":"69"}

问题是如何发送和接收所有以上？

Answer 1

使用SBJson框架。并执行以下操作：

-(void)requestProjects
{


    //I prepare the string

    NSString *preparedString=[NSString stringWithFormat:@"%@ %@", self.lastDate, self.currentCategory];
    NSDictionary *jsonDict = [NSDictionary dictionaryWithObject:preparedString forKey:@"request"];

    //Prepare convert to json string
    NSString *jsonRequest = [jsonDict JSONRepresentation];

    NSLog(@"jsonRequest is %@", jsonRequest);

    //Set the URL YOU WILL PROVIDE

    NSURL *url = [NSURL URLWithString:@"http:xxxxxxxxxxxxxxxxxxx"];

    //PREPARE the request
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];

    //Prepare data which will contain the json request string.
    NSData *requestData = [NSData dataWithBytes:[jsonRequest UTF8String] length:[jsonRequest length]];

    //Set the propreties of the request 
    [request setHTTPMethod:@"POST"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    [request setValue:[NSString stringWithFormat:@"%d", [requestData length]] forHTTPHeaderField:@"Content-Length"];
    [request setValue:jsonRequest forHTTPHeaderField:@"Query-string"];
    //set the data prepared
    [request setHTTPBody: requestData];

    //Initialize the connection with request
    NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];
    //Start the connection
    [delegate showIndicator];
    [connection start];

}


//delegate methods:

//METHODS TO HANßDLE RESPONSE
#pragma mark NSURLConnection delegate methods
//WHen receiving the response
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

    NSLog(@" Did receive respone");
    [responseData setLength:0];


}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    //While receiving the response data
    [responseData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    //When failed just log
     [delegate hideIndicator];
    NSLog(@"Connection failed!");
    NSLog(@"Error %@", error);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    //When the response data is downloaded 
   // NSLog(@" Data obtained %@", responseData);
    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
   // NSLog(@" Response String %@", responseString);
    //converted response json string to a simple NSdictionary
    //If the response string is really JSONABLE I will have the data u sent me displayed succefully

    NSMutableArray *results = [responseString JSONValue];
    NSLog(@"Response: %@", results);
/// la la al alal alaa
}

您的后端应该定义 Json 中的响应的样子

Answer 2

请参阅 NSJsonSerialization 类。这是ios5.0中新包含的。这是满足您需求的最灵活的一种。您可以在苹果开发者网站中访问它。
链接到 NSJSONSerialization