字典与json字符串互解

+ (NSString *)arrayToJSONString:(NSArray *)array
{
    if (array==nil) {
        return @"";
    }
    NSError *error = nil;
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:array options:kNilOptions error:&error];
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    return jsonString;
    
}

+ (NSArray *)arrWithJsonString:(NSString *)jsonString
{
    if (jsonString == nil) {
        return nil;
    }
    
    NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *err;
    NSArray *dic = [NSJSONSerialization JSONObjectWithData:jsonData
                                                        options:NSJSONReadingMutableContainers
                                                          error:&err];
    if(err)
    {
        //"json解析失败：%@",err);
        return nil;
    }
    return dic;
}

+ (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)
    {
        //"json解析失败：%@",err);
        return nil;
    }
    return dic;
}