使用SBJson或其他JSON库将对象转换为Json

Question

我需要一个易于使用的库whit示例，用于将NSObject转换为JSON并再次返回，我在网上发现了大量用于解析JSon的解析示例但在使用SBJSON将NSObject转换为JSON时没有太多，Anybody正文有一个很好的教程或者将NSObject转换为JSON的示例代码？

Answer 1

With SBJSON, it's really simple.

NSString *myDictInJSON = [myDict JSONRepresentation];
NSString *myArrayInJSON = [myArray JSONRepresentation];

Of course, to go the other way array, do:

NSDictionary *myDict = [myDictInJSON JSONValue];
NSArray *myArray = [myArrayInJSON JSONValue];

Answer 2

Using SBJson , to convert a object to JSON string, you have to override the proxyForJson method. Like the following,

The .h file,

@interface MyCustomObject : NSObject {
    NSString *receiverFirstName;
    NSString *receiverMiddleInitial;
    NSString *receiverLastName;
    NSString *receiverLastName2;
}
@property (nonatomic, retain) NSString *receiverFirstName;
@property (nonatomic, retain) NSString *receiverMiddleInitial;
@property (nonatomic, retain) NSString *receiverLastName;
@property (nonatomic, retain) NSString *receiverLastName2;

- (id) proxyForJson;
- (int) parseResponse :(NSDictionary *) receivedObjects;
}

In the implementation file,

    - (id) proxyForJson {

        return [NSDictionary dictionaryWithObjectsAndKeys:
            receiverFirstName, @"ReceiverFirstName",
            receiverMiddleInitial, @"ReceiverMiddleInitial",
            receiverLastName, @"ReceiverLastName",
            receiverLastName2, @"ReceiverLastName2",
            nil ];
    }

And to get the object from the JSON string you have to write a parseResponse method like this,

- (int) parseResponse :(NSDictionary *) receivedObjects {
    self.receiverFirstName = (NSString *) [receivedObjects objectForKey:@"ReceiverFirstName"];
    self.receiverLastName = (NSString *) [receivedObjects objectForKey:@"ReceiverLastName"];

    /* middleInitial and lastname2 are not required field. So server may return null value which
     eventually JSON parser return NSNull. Which is unrecognizable by most of the UI and functions.
     So, convert it to empty string. */ 
    NSString *middleName = (NSString *) [receivedObjects objectForKey:@"ReceiverMiddleInitial"];
    if ((NSNull *) middleName == [NSNull null]) {
        self.receiverMiddleInitial = @"";
    } else {
        self.receiverMiddleInitial = middleName;
    }

    NSString *lastName2 = (NSString *) [receivedObjects objectForKey:@"ReceiverLastName2"];
    if ((NSNull *) lastName2 == [NSNull null]) {
        self.receiverLastName2 = @"";
    } else {
        self.receiverLastName2 = lastName2;
    }

    return 0;
}

Answer 3

From JSON String to Objects:

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

// gives array as output

id objectArray = [parser objectWithString:@"[1,2,3]"]; 

// gives dictionary as output

id objectDictionary = [parser objectWithString:@"{\"name\":\"xyz\",\"email\":\"xyz@email.com\"}"]; 

From Objects to JSON String:

SBJsonWriter *writer = [[SBJsonWriter alloc] init];

id *objectArray = [NSArray arrayWithObjects:@"Hello",@"World", nil];

// Pass an Array or Dictionary object.

id *jsonString = [writer stringWithObject:objectArray];