如何在php中访问私有属性，甚至可以？

Question

I have a simple example of code in which i would like to set the private property $ttlBal.

<$php
$balance = new Customer;
$greeting = fopen("greeting.txt", "r");
while(!feof($greeting)){
    echo fgets($greeting) . "<br>";
}
fclose($greeting);
$balance->acctBal = 12;
$balance->deposits = 12;
$balance->fdr = 12;


$balance->findAvail($balance->acctBal, $balance->deposits, $balance->ttlBal);
class Customer{
    public $acctBal; 
    public $deposits;
    private $acctAvail;
    private $ttlBal;
    public $fdr;

    public function findAvail($bal, $dep, $ttlBal){
        echo $this->ttlBal = $bal - $dep;
    }
}
?>

This brings about an error that I cannot access the private property $ttlBal. In which way can I access this.

Answer 1

You should add a public setter method to your class:

class Foo {
    private $var;

    public function setVar($value) {
        $this->var = $value;
    }
}

Also in many cases protected is what you want if you use private . If you just want to hide the variable from public access, use protected .

Answer 2

Youe error is here $balance->ttlBal

Either you will make the property public or you would implement get() and set() methods for it in Customer class.

As an example

public function get_ttlBal()
{
    return $this->ttlBal;
}

and then you can call

$balance->findAvail($balance->acctBal, $balance->deposits, $balance->get_ttlBal());

Answer 3

To access private properties, previously set by setter function, you should write and use getter method.

public function getVar() {
    return $this->_var;
}