/* Create a Foundation object from JSON data. Set the NSJSONReadingAllowFragments option if the parser should allow top-level objects that are not an NSArray or NSDictionary. Setting the NSJSONReadingMutableContainers option will make the parser generate mutable NSArrays and NSDictionaries. Setting the NSJSONReadingMutableLeaves option will make the parser generate mutable NSString objects. If an error occurs during the parse, then the error parameter will be set and the result will be nil.The data must be in one of the 5 supported encodings listed in the JSON specification: UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE. The data may or may not have a BOM. The most efficient encoding to use for parsing is UTF-8, so if you have a choice in encoding the data passed to this method, use UTF-8.*/
+ (id)JSONObjectWithData:(NSData *)data options:(NSJSONReadingOptions)opt error:(NSError **)error;/* Create a JSON object from JSON data stream. The stream should be opened and configured. All other behavior of this method is the same as the JSONObjectWithData:options:error: method.*/
+ (id)JSONObjectWithStream:(NSInputStream *)stream options:(NSJSONReadingOptions)opt error:(NSError **)error;

- (void)jsonParse{//初始化文件路径。NSString* path  = [[NSBundle mainBundle] pathForResource:@"nanjing" ofType:@"txt"];//将文件内容读取到字符串中，注意编码NSUTF8StringEncoding 防止乱码，NSString* jsonString = [[NSString alloc] initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];//将字符串写到缓冲区。NSData* jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];//解析json数据，使用系统方法 JSONObjectWithData:  options: error:NSDictionary* dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableLeaves error:nil];//接下来一步一步解析。知道得到你想要的东西。NSArray* arrayResult =[dic objectForKey:@"results"]; NSDictionary* resultDic = [arrayResult objectAtIndex:0];NSDictionary* geometryDic = [resultDic objectForKey:@"geometry"];NSLog(@"geometryDic: %@,  resultDic:%@",geometryDic,resultDic);NSDictionary* locationDic = [geometryDic objectForKey:@"location"];NSNumber* lat = [locationDic objectForKey:@"lat"];NSNumber* lng = [locationDic objectForKey:@"lng"];NSLog(@"lat = %@, lng = %@",lat,lng);[jsonString release];}

- (void)jsonParse{//初始化网络路径。NSString* path  = @"http://maps.googleapis.com/maps/api/geocode/json?address=nanjing&sensor=true";//初始化 url NSURL* url = [NSURL URLWithString:path];//将文件内容读取到字符串中，注意编码NSUTF8StringEncoding 防止乱码，NSString* jsonString = [[NSString alloc]initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];//将字符串写到缓冲区。NSData* jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];//解析json数据，使用系统方法 JSONObjectWithData:  options: error:NSDictionary* dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableLeaves error:nil];//一下为自定义解析， 自己想怎么干就怎么干NSArray* arrayResult =[dic objectForKey:@"results"]; NSDictionary* resultDic = [arrayResult objectAtIndex:0];NSDictionary* geometryDic = [resultDic objectForKey:@"geometry"];NSLog(@"geometryDic: %@,  resultDic:%@",geometryDic,resultDic);NSDictionary* locationDic = [geometryDic objectForKey:@"location"];NSNumber* lat = [locationDic objectForKey:@"lat"];NSNumber* lng = [locationDic objectForKey:@"lng"];NSLog(@"lat = %@, lng = %@",lat,lng);[jsonString release];}

- (void)jsonParse{//初始化网络路径。NSString* path  = @"http://maps.googleapis.com/maps/api/geocode/json?address=nanjing&sensor=true";//初始化 url NSURL* url = [NSURL URLWithString:path];NSURLRequest* request = [NSURLRequest requestWithURL:url];//将请求到的字符串写到缓冲区。NSData* jsonData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];//解析json数据，使用系统方法 JSONObjectWithData:  options: error:NSDictionary* dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableLeaves error:nil];//一下为自定义解析， 自己想怎么干就怎么干NSArray* arrayResult =[dic objectForKey:@"results"]; NSDictionary* resultDic = [arrayResult objectAtIndex:0];NSDictionary* geometryDic = [resultDic objectForKey:@"geometry"];NSLog(@"geometryDic: %@,  resultDic:%@",geometryDic,resultDic);NSDictionary* locationDic = [geometryDic objectForKey:@"location"];NSNumber* lat = [locationDic objectForKey:@"lat"];NSNumber* lng = [locationDic objectForKey:@"lng"];NSLog(@"lat = %@, lng = %@",lat,lng);}