正確執行對象參數

Question

我只是想確保我正確地做到了這一點。我有點困惑$this->parameter,$parameter和public $parameter

這是我正在做的一個例子。我希望任何聲明爲公開的東西都可以通過$instance->parameter方法訪問。這是否意味着點訪問也會起作用？我是多餘的嗎？

class Email { 
    public $textBody; 
    public $attachments; 
    public $subject; 
    public $emailFolder; 

    function __construct($header) { 
     $this->head = $header; 
     $this->attachments = []; 
     preg_match('/(?<=Subject:).*/', $this->head, $match); 
     $this->subject = $match[0]; 
     if ($this->subject) { 
      $this->subject = "(No Subject)"; 
     } 
     preg_match('/(?<=From:).*/', $this->head, $match); 
     $this->fromVar = $match[0]; 
     preg_match('/(?<=To:).*/', $this->head, $match); 
     $this->toVar = $match[0]; 
     preg_match('/((?<=Date:)\w+,\s\w+\s\w+\s\w+)|((?<=Date:)\w+\s\w+\s\w+)/', $this->head, $match); 
     $this->date = $match[0]; 
     $this->date = str_replace(',', '', $this->date); 
     $this->textBody = ""; 
    } 

    function generateParsedEmailFile($textFile) { 
     if (!(file_exists("/emails"))) { 
      mkdir("/emails"); 
     } 

     $this->emailFolder = 

     $filePath = "/emails/".$this->subject.$this->date; 
     while (file_exists($filePath)) { 
      $filePath = $filePath.".1"; 
     } 
      # ......code continues 
    } 
} 

Answer 1

不，.僅用於連接字符串。 public變量（以及函數）將可以使用->運算符從「外部」直接訪問，而protected和private變量（和函數）需要訪問getter和setter函數。舉例如下：

class MyClass { 
    public $variableA; 
    protected $variableB; 

    public function setB($varB) { 
     $this->variableB = $varB; 
    } 

    public function getB() { 
     return $this->variableB; 
    } 
} 

$object = new MyClass(); 

$object->variableA = "new Content"; // works 
$object->variableB = "new Content"; // generates an error 
$object->setB("new Content");  // works