- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    NSDictionary *dict = @{@"aaa":@"11",@"bb":@"22",@"cc":@"33"};
    
    NSString *str = [self dictionaryToJson:dict];
    NSDictionary *dict1 = [self dictionaryWithJsonString:str];
    
    NSLog(@"%@",str);
    NSLog(@"%@",dict1);
    
}

#pragma mark 字符串转化成字典
- (NSDictionary *)dictionaryWithJsonString:(NSString *)jsonString {
    
    if (jsonString == nil) {
        
        return nil;
        
    }
    
    NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *err;
    NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData
                         
                                                        options:NSJSONReadingMutableContainers
                         
                                                          error:&err];
    if(err) {
        
        NSLog(@"json解析失败：%@",err);
        return nil;
    }
    
    return dic;
}

#pragma mark 字典转化成字符串
- (NSString*)dictionaryToJson:(NSDictionary *)dic

{
    
    NSError *parseError = nil;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&parseError];
    return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}