性狀 Trait
性狀(Trait)是PHP5.4.0引入的概念，既像接口砌们，也像類，但是兩者都不是浪感。
性狀有兩個(gè)作用：1.表明類可以做什么（像接口）饼问；2.將代碼模塊化（像類)。
性狀能把模塊化的實(shí)現(xiàn)方式注入多個(gè)無關(guān)的類中（類與類之間沒有業(yè)務(wù)功能相似處）莱革，而且還能促進(jìn)代碼重構(gòu)讹开。

性狀創(chuàng)建：

trait MyTrait
{
    protected $trait_test_var;
    protected $trait_test_result;

    public function setVar($test_var)
    {
        $this->trait_test_var = $test_var;
        $this->trait_test_result = $this->trait_test_var + 1;
    }

    public function getVarResult()
    {
        return $this->trait_test_result;
    }
}

然后旦万，再創(chuàng)建一個(gè)測試類：

// 父類（交通工具）
class Vehicle
{
    protected $driver;
    protected $drive_style;

    public function __construct($driver)
    {
        $this->driver = $driver;
    }

    public function doThing()
    {
        echo 'I am ' . $driver . ' and,i am driving';
    }

}

//子類(小汽車)
class Car extends Vehicle
{
    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and,i am driving car';
    }
}

創(chuàng)建好之后镶蹋。
在子類car中加入"use MyTrait"

class Car extends Vehicle
{

    use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and,i am driving car';
    }
}

然后，使用car：

$car = new Car('jeep');
$car->setVar(1);
var_dump($car->getVarResult()); // 輸出 2

如果還有另外一輛車狰腌，例如 jeep

class Jeep extends Vehicle
{
    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and i am driving jeep';
    }
}

這輛 jeep也想使用 MyTrait 時(shí)，我們也可以在其中加入 "use MyTrait"琼腔，像這樣

class Jeep extends Vehicle
{
    use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and i am driving jeep';
    }
}

然后使用：

$car = new Car('jeep');
$car->setVar(1);
var_dump($car->getVarResult()); // 輸出 2

$jeep = new Jeep('jeep');
$jeep->setVar(3);
var_dump($jeep->getVarResult());  // 輸出 4

但是踱葛，這樣每一個(gè)子類中都使用"use MyTrait "引入，這樣做不大好甥材，可以進(jìn)行優(yōu)化。
可以在父類Vehicle中使用"use MyTrait"引入洲赵，像這樣：

class Vehicle
{
    use MyTrait;

    protected $driver;
    protected $drive_style;

    public function __construct($driver)
    {
        $this->driver = $driver;
    }

    public function doThing()
    {
        echo 'I am ' . $driver . ' and,i am driving';
    }

}


class Car extends Vehicle
{

    #use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and,i am driving car';
    }
}

class Jeep extends Vehicle
{
    #use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and i am driving jeep';
    }
}

這樣做商蕴，同樣可以使用。

完整代碼如下：

trait MyTrait
{
    protected $trait_test_var;
    protected $trait_test_result;

    public function setVar($test_var)
    {
        $this->trait_test_var = $test_var;
        $this->trait_test_result = $this->trait_test_var + 1;
    }

    public function getVarResult()
    {
        return $this->trait_test_result;
    }
}


class Vehicle
{
    use MyTrait;

    protected $driver;
    protected $drive_style;

    public function __construct($driver)
    {
        $this->driver = $driver;
    }

    public function doThing()
    {
        echo 'I am ' . $driver . ' and,i am driving';
    }

}


class Car extends Vehicle
{

    #use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and,i am driving car';
    }
}

class Jeep extends Vehicle
{
    #use MyTrait;

    public function doThing()
    {
        echo 'I am ' . $this->driver . ' and i am driving jeep';
    }
}




$car = new Car('jeep');
$car->setVar(1);
var_dump($car->getVarResult()); // 輸出 2

$jeep = new Jeep('jeep');
$jeep->setVar(3);
var_dump($jeep->getVarResult());