1.解析json 

使用开源json包，项目地址： 

      

NSData * responseData = [respones responseData]; 

      

     NSString * strResponser = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; 

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

     NSMutableDictionary *dicMessageInfo = [parser objectWithString:strResponser]; // 解析成json解析对象 

[parser release]; 

     //发送者 

     NSString * sender = [dicMessageInfo objectForKey:@"sender"]; 

2.json嵌套对象解析： 

//要上传的字符串 

    NSString *dataStr=[[NSString alloc] initWithString:@"{\"cross\":{\"1\":\"true\",\"2\":\"false\",\"3\":\"true\"}}"]; 

//获取响应返回字符串 

NSData * responseData = [respones responseData]; 

        

        NSString * strResponser = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];

//嵌套解析 

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

            

            NSMutableDictionary *dicMessageInfo = [parser objectWithString:strResponser]; // 解析成json解析对象 

            

            NSMutableDictionary * cross = [dicMessageInfo objectForKey:@"cross"]; 

            

            NSString *cross1= [cross objectForKey:@"1"]; 

            //解析json到各个字符串 

            //发送者 

            [parser release]; 

            NSLog(@"cross1: %@",cross1); 

3.拼接json字符串 

通过使用SBJson中的SBJsonWriter类的方法- (NSString*)stringWithObject:(id)value可以将一个对象中的值格式化为json字符串，符合key/value格式的数据封装到NSDictionary后可以使用该方法进行格式化，其他数据通过拼接字符串的方式格式化。 

在拼接过程中可以使用类NSMutableString的方法： 

- (void)appendString:(NSString *)aString;、 

- (void)appendFormat:(NSString *)format, ... NS_FORMAT_FUNCTION(1,2); 

动态添加字符串。 

拼接的字符串可通过json在线验证的方式验证其格式是否正确，网址为： 

 

-(NSString *) getJsonString 

{

 

    NSMutableString *json = [NSMutableString stringWithCapacity:128]; 

    NSString *jsonString=nil; 

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

    [json appendString:@"{\"data\":{"]; 

    [json appendFormat:@"\"%@\":\"%d\",",@"reset",reset]; 

    if(missionStatus!=NULL) 

    {

 

        jsonString=[writer stringWithObject:status]; 

        if(jsonString!=NULL) 

        {

 

            [json appendString:@"\"status\":"]; 

            [json appendString:jsonString]; 

        } 

    } 

    [json appendString:@"}}"]; 

    return json; 

} 

4.利用多个NSDictionary，拼接多层嵌套的json字符串，减少因手工拼接忘记加引号导致的json格式错误 

示例代码： 

NSDictionary *dataDictionary= [NSDictionary dictionaryWithObjectsAndKeys:mac,@"mac", 

                                   game,@"game", 

                                   devicetoken,@"devicetoken", 

                                   device,@"device", 

                                   gv,@"gv", 

                                   lang,@"lang", 

                                   os,@"os", 

                                   hardware,@"hardware", 

                                   down,@"down",nil]; 

    NSDictionary *parmDictionary= [NSDictionary dictionaryWithObjectsAndKeys:@"getSession",@"act", 

                                   dataDictionary,@"data",nil]; 

    NSDictionary *jsonDictionary=[NSDictionary dictionaryWithObjectsAndKeys:pv,@"pv", 

                                  parmDictionary,@"param",nil]; 

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

    

    NSString *jsonString=nil; 

    jsonString=[writer stringWithObject:jsonDictionary]; 

    NSLog(@"%@",jsonString); 

5.json字符串在线校验网址： 

http://jsonlint.com/