我正在编写自己的php类，该类中有多个函数。类似这样：

class JSON_API_Hello_Controller {

    public function test_cat(){
        global $json_api;

        $posts = $json_api->introspector->get_posts(array( \'cat\' => 3));
        return $this->posts_object_result_bycat($posts);
    }

    public function test_cat1() {
        global $json_api;

        $posts = $json_api->introspector->get_posts(array( \'cat\' => 2));
        return $this->posts_object_result_bycat($posts);
    }

    protected function posts_object_result_bycat($posts) {
        global $wp_query;

        return array(
            \'count\' => count($posts),
            \'pages\' => (int) $wp_query->max_num_pages,
            \'posts\' => $posts
        );
    }

    public function mix_cat(){

        $first_cat = $this->test_cat();
        $second_cat = $this->test_cat1();
        $json1 = json_decode($first_cat , true);
        $json2 = json_decode($second_cat, true);
        $final_array = array_merge($json1, $json2);
        // Finally encode the result back to JSON.
        $final_json = json_encode($final_array);
    }

} 

我试过这样的东西。我想打电话给test_cat() 和test_cat1() 其他函数中的函数，如mix_cat() 在同一个类中。两种功能(test_cat() &；test_cat1()) 返回json对象。两个返回的json对象都将加入mix_cat() 作用请建议我如何拨打testcat() &；test_cat1() 中的函数mix_cat() 并将这两个函数的结果mix_cat() 作用

function mergeToJSON( $obj1, $obj2 ) {

    $json1 = $this->test_cat();
    $json2 = $this->test_cat1();

    if ( $json1 === FALSE || $json2 === FALSE ) {
        return;
    }

    $array1 = json_decode( $json1, TRUE );
    $array2 = json_decode( $json2, TRUE );
    $data = array_merge( $array1, $array2 );

    return json_encode( $data );
}