//创建单个字典
        NSDictionary *dic = [NSDictionary dictionaryWithObject:@"obj" forKey:@"key"];
        //创建多个字典
        NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"obj1", @"key1",@"obj2", @"key2",nil];
        //根据已有字典创建新的字典  
    NSDictionary *dic1 = [NSDictionary dictionaryWithDictionary:dic];
    //将从新分配的字典初始化为键-对象对
    NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"obj1",@"key1",@"obj2",@"key2",nil];
    //特殊语法创建
    NSDictionary *dic = @{obj1,key1,obj2,key2,.......};

//创建单个字典
        NSDictionary *dic = [NSDictionary dictionaryWithObject:@"obj" forKey:@"key"];
        //创建多个字典
        NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"obj1", @"key1",@"obj2", @"key2",nil];
        //根据已有字典创建新的字典  
    NSDictionary *dic1 = [NSDictionary dictionaryWithDictionary:dic];
    //将从新分配的字典初始化为键-对象对
    NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"obj1",@"key1",@"obj2",@"key2",nil];
    //特殊语法创建
    NSDictionary *dic = @{obj1,key1,obj2,key2,.......};