php - Doctrine : OneToOne entity relationship doesn't work

Question

我正在使用 php，我有两个实体 Message 和 Post。帖子是消息实体中的一个属性，它应该是一对一的单向关系。但是当我在我的 Controller 中调用 message->getPost()->getText() 时，我收到了这个错误消息:

Trying to get property of non-object in C:\wamp64\www\Test\monApplication\controller\mainController.php

消息实体:

<?php

/**
 * @Entity
 * @Table(name="message")
 */
class message{

    /** @Id @Column(type="integer")
     *  @GeneratedValue
     */
    public $id;

    /**
     * @ORM\OneToOne(targetEntity="post", cascade={"persist"})
     * @JoinColumn(name="post", referencedColumnName ="id")
     */
    private $post;

    /** @Column(type="integer") */
    public $likes;

    public function getPost(){
        return $this->post;
    }
    public function getLikes(){
         return $this->likes;
    }
}

?>

Post 实体

<?php

/**
 * @Entity
 * @Table(name="post")
 */
class post{

    /** @Id @Column(type="integer")
     *  @GeneratedValue
     */
    public $id;

    /** @Column(type="string", length=2000) */
    public $texte;

    /** @Column(type="string", length=200) */
    public $image;

    /** @Column(type="TIMESTAMP", length=4000) */
    public $date;
}

?>

我的数据库连接类:

<?php

define ('HOST', 'localhost') ;
define ('USER', 'root'  ) ;
define ('PASS', '' ) ;
define ('DB', 'tp' ) ;

use Doctrine\ORM\Tools\Setup;
use Doctrine\ORM\EntityManager;

class dbconnection{

private static $instance=null, $entityManager;
private $error=null ;

private function __construct(){
    $config = Setup::createAnnotationMetadataConfiguration(array("../../monApplication/model/"), true);

    $param = array(
    'dbname' => DB,
    'user'  => USER,
    'password' => PASS,
    'host'  => HOST,
    'driver' => 'pdo_mysql');

    try{
        self::$entityManager = EntityManager::create($param, $config);
    }
    catch(Exception $e) {
        echo "Probleme connexion base de données:".$e->getMessage();
        $this->error = $e->getMessage();
    }

}

public static function getInstance(){
    if(self::$instance == null){
        self::$instance = new dbconnection();
    }
    return self::$instance;
}

public function closeConnection(){
    self::$instance=null;
}

public function getEntityManager(){
    if(!empty(self::$entityManager))
        return self::$entityManager;
    else
        return NULL;
}


public function __clone(){

}

public function getError(){
    return $this->error;
}

}

我的主 Controller :

<?php

class mainController
{

    public static function showMessage($request,$context){
        $messages = messageTable::getAllMessages();
        echo $message[0]->getPost()->text;   

        return context::SUCCESS;
    }
}

最后我的项目架构是这样的:

Answer 1

努力改变

private $post;

到

public $post;

(你应该使用 protected 变量)

你还有另外两个问题:

/** @Column(type="string", length=2000) */
public $texte;

应该是:

/** @Column(type="text") */
public $texte;

因为字符串的长度限制为 255 个字符。

你的属性是“texte”所以你应该有

echo $message[0]->getPost()->texte; 

代替

echo $message[0]->getPost()->text;