IOS5.0 自带JSON解析

IOS5.0开始支持JSON，所以不用第三方的解析了。

//将Foundation(NSDictionary、NSData) 转换为JSon格式的NSData 用来发送

//+ dataWithJSONObject:options:error:

 

//将JSON格式的Data转换为Foundation(NSDictionary、NSData)   用来解析

//+ JSONObjectWithData:options:error:

code:

https://github.com/cokecoffe/ios-demo/tree/master/HTTP

 解析json成dic对象

 -(void)fetchedData:(NSData*)responseData {//parse out the json dataNSError* error;
 NSDictionary* json =[NSJSONSerialization
 JSONObjectWithData:responseData //1

 options:kNilOptions
 error:&error];

 NSArray* latestLoans =[json objectForKey:@"loans"]; //2

 NSLog(@"loans: %@", latestLoans); //3
 }

 把对象生成json string
 //build an info object and convert to json
 NSDictionary* info =[NSDictionary dictionaryWithObjectsAndKeys:[loan objectForKey:@"name"],
 @"who",
 [(NSDictionary*)[loan objectForKey:@"location"]
 objectForKey:@"country"],
 @"where",
 [NSNumber numberWithFloat: outstandingAmount],
 @"what",
 nil];

 //convert object to data
 NSData* jsonData =[NSJSONSerialization dataWithJSONObject:info
 options:NSJSONWritingPrettyPrinted error:&error];

 //print out the data contents
 jsonSummary.text =[[NSString alloc] initWithData:jsonData
 encoding:NSUTF8StringEncoding];

 添加json方法至dic
 @interfaceNSDictionary(JSONCategories)
 +(NSDictionary*)dictionaryWithContentsOfJSONURLString:(NSString*)urlAddress;
 -(NSData*)toJSON;
 @end

 @implementationNSDictionary(JSONCategories)
 +(NSDictionary*)dictionaryWithContentsOfJSONURLString:(NSString*)urlAddress{
 NSData* data =[NSData dataWithContentsOfURL:[NSURL URLWithString: urlAddress]];
 __autoreleasing NSError* error =nil;
 id result =[NSJSONSerialization JSONObjectWithData:data
 options:kNilOptions error:&error];
 if(error !=nil)returnnil;
 return result;
 }

 -(NSData*)toJSON{
 NSError* error =nil;
 id result =[NSJSONSerialization dataWithJSONObject:self
 options:kNilOptions error:&error];
 if(error !=nil)returnnil;
 return result;
 }@end

 使用列子
 NSDictionary* myInfo =[NSDictionary dictionaryWithContentsOfJSONURLString:@"http://www.yahoo.com/news.json"];
 NSDictionary* information =[NSDictionary dictionaryWithObjectsAndKeys:@"orange",@"apple",@"banana",@"fig",nil];
 NSData* json =[information toJSON];

 判断是否可json化

 BOOL isTurnableToJSON =[NSJSONSerialization isValidJSONObject: object]