我已经制作了一个插件，其中需要post meta？现在我得到了不需要的自定义字段。下面是我用来在post type=recommendation中添加自定义meta的代码

add_meta_box(\'plugin-recommendation-box\', \'Recommendation\', \'add_plugin_recommendation_box\', \'recommendations\', \'normal\', \'default\');


    function add_plugin_recommendation_box(){
    global $post;
    $title = get_post_meta($post->ID, \'recommendation_title1\', true);
    $price = get_post_meta($post->ID, \'recommendation_price\', true);
    $reg_price = get_post_meta($post->ID, \'recommendation_reg_price\', true);
    $rating=    get_post_meta($post->ID, \'recommendation_rating\', true);
    $pros=get_post_meta($post->ID, \'recommendation_pros\', true);
    $cons=get_post_meta($post->ID, \'recommendation_cons\', true);
    $specs=get_post_meta($post->ID, \'recommendation_specs\', true);
    $url=get_post_meta($post->ID, \'recommendation_url\', true);
    $custom_url=get_post_meta($post->ID, \'custom_url\', true);
    $rec_short_dec=get_post_meta($post->ID, \'rec_short_dec\', true);
    $ratings=get_post_meta($post->ID, \'recommendation_ratings\', true);
    $trybtn=get_post_meta($post->ID, \'recommendation_trybtn\', true);
    $curr=get_post_meta($post->ID, \'recommendation_currency\', true);
    $compare_subtitle=get_post_meta($post->ID, \'compare_subtitle\', true);
    $compare_price_1=get_post_meta($post->ID, \'compare_price_1\', true);
    $compare_price_2=get_post_meta($post->ID, \'compare_price_2\', true);
    $compare_price_3=get_post_meta($post->ID, \'compare_price_3\', true);
    $compare_price_4=get_post_meta($post->ID, \'compare_price_4\', true);
    $compare_price_plan_1=get_post_meta($post->ID, \'compare_price_plan_1\', true);
    $compare_price_plan_2=get_post_meta($post->ID, \'compare_price_plan_2\', true);
    $compare_price_plan_3=get_post_meta($post->ID, \'compare_price_plan_3\', true);
    $compare_price_plan_4=get_post_meta($post->ID, \'compare_price_plan_4\', true);
    $compare_price_plan_short_desc=get_post_meta($post->ID, \'compare_price_plan_short_desc\', true);
    $compare_price_short_desc=get_post_meta($post->ID, \'compare_price_short_desc\', true);
    $offer_price_short_desc=get_post_meta($post->ID, \'offer_price_short_desc\', true);
    $offer_sale_text=get_post_meta($post->ID, \'offer_sale_text\', true);
    $offer_image=get_post_meta($post->ID, \'offer_image\', true);
    $offer_subtitle_text=get_post_meta($post->ID, \'offer_subtitle_text\', true);
    $coupon_code=get_post_meta($post->ID, \'coupon_code\', true);
    $coupon_detail=get_post_meta($post->ID, \'coupon_detail\', true);
    $coupon_start_date=get_post_meta($post->ID, \'coupon_start_date\', true);
    $coupon_end_date=get_post_meta($post->ID, \'coupon_end_date\', true);
    $top_10_basic_feature1=get_post_meta($post->ID, \'top_10_basic_feature1\', true);
    $top_10_basic_feature2=get_post_meta($post->ID, \'top_10_basic_feature2\', true);
    $top_10_basic_feature3=get_post_meta($post->ID, \'top_10_basic_feature3\', true);
    $top_10_basic_feature4=get_post_meta($post->ID, \'top_10_basic_feature4\', true);
    $top_10_basic_feature5=get_post_meta($post->ID, \'top_10_basic_feature5\', true);
    $top_10_advance_feature1=get_post_meta($post->ID, \'top_10_advance_feature1\', true);
    $top_10_advance_feature2=get_post_meta($post->ID, \'top_10_advance_feature2\', true);
    $top_10_advance_feature3=get_post_meta($post->ID, \'top_10_advance_feature3\', true);
    $top_10_advance_feature4=get_post_meta($post->ID, \'top_10_advance_feature4\', true);
    $top_10_advance_feature5=get_post_meta($post->ID, \'top_10_advance_feature5\', true);
    $rec_expert_feature1=get_post_meta($post->ID, \'rec_expert_feature1\', true);
    $rec_expert_feature2=get_post_meta($post->ID, \'rec_expert_feature2\', true);
    $expert_feature1_title=get_post_meta($post->ID, \'expert_feature1_title\', true);
    $expert_feature2_title=get_post_meta($post->ID, \'expert_feature2_title\', true); 
    $expert_trend=get_post_meta($post->ID, \'expert_trend\', true);   
    $sch_popup_feature1=get_post_meta($post->ID, \'sch_popup_feature1\', true);
    $sch_popup_feature2=get_post_meta($post->ID, \'sch_popup_feature2\', true);