[转]php的public、protected、private三种访问控制模式的区别

FROM :http://blog.163.com/weiwenjuan_bj/blog/static/14035033620129304183850/?suggestedreading public:公有类型 在子类中可以通过self::var调用public方法或属性,parent::method调用父类方法 在实例中可以能过$obj-var来调用 public类型的方法或属性 pr

FROM : http://blog.163.com/weiwenjuan_bj/blog/static/14035033620129304183850/?suggestedreading

public: 公有类型

        在子类中可以通过self::var调用public方法或属性,parent::method调用父类方法

        在实例中可以能过$obj->var 来调用　public类型的方法或属性

protected: 受保护类型
        在子类中可以通过self::var调用protected方法或属性,parent::method调用父类方法

        在实例中不能通过$obj->var 来调用  protected类型的方法或属性

private: 私有类型
 该类型的属性或方法只能在该类中使用，在该类的实例、子类中、子类的实例中都不能调用私有类型的属性和方法

2.self 和　parent 的区别
  a).在子类中常用到这两个对像。他们的主要区别在于self可以调用父类中的公有或受保护的属性，但parent不可以调用

  b).self:: 它表示当前类的静态成员(方法和属性)　与 $this　不同,$this是指当前对像

附代码：

<span> 1</span> <span>php
</span><span> 2</span> <span>/*</span><span>*
</span><span> 3</span> <span> * parent　只能调用父类中的公有或受保护的方法，不能调用父类中的属性
</span><span> 4</span> <span> * self 　可以调用父类中除私有类型的方法和属性外的所有数据
</span><span> 5</span>  <span>*/</span>
<span> 6</span> <span>class</span><span> User{
</span><span> 7</span>     <span>public</span> <span>$name</span><span>;
</span><span> 8</span>     <span>private</span> <span>$passwd</span><span>;
</span><span> 9</span>     <span>protected</span> <span>$email</span><span>;    
</span><span>10</span>     <span>public</span>  <span>function</span><span> __construct(){
</span><span>11</span>         <span>//</span><span>print __CLASS__." ";</span>
<span>12</span>         <span>$this</span>->name= 'simple'<span>;
</span><span>13</span>         <span>$this</span>->passwd='123456'<span>;
</span><span>14</span>         <span>$this</span>->email = 'bjbs_270@163.com'<span>;
</span><span>15</span> <span>    }    
</span><span>16</span>     <span>public</span> <span>function</span><span> show(){
</span><span>17</span>         <span>print</span> "good "<span>;
</span><span>18</span> <span>    }    
</span><span>19</span>     <span>public</span> <span>function</span><span> inUserClassPublic() {
</span><span>20</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>21</span> <span>    }    
</span><span>22</span>     <span>protected</span>  <span>function</span><span> inUserClassProtected(){
</span><span>23</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>24</span> <span>    }    
</span><span>25</span>     <span>private</span> <span>function</span><span> inUserClassPrivate(){
</span><span>26</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>27</span> <span>    }
</span><span>28</span> <span>}
</span><span>29</span> 
<span>30</span> <span>class</span> simpleUser <span>extends</span><span> User {    
</span><span>31</span>     <span>public</span> <span>function</span><span> __construct(){        
</span><span>32</span>         <span>//</span><span>print __CLASS__." ";</span>
<span>33</span>         parent::<span>__construct();
</span><span>34</span> <span>    }
</span><span>35</span>     
<span>36</span>     <span>public</span> <span>function</span><span> show(){
</span><span>37</span>         <span>print</span> <span>$this</span>->name."//public "<span>;        
</span><span>38</span>         <span>print</span> <span>$this</span>->passwd."//private "<span>;
</span><span>39</span>         <span>print</span> <span>$this</span>->email."//protected "<span>;
</span><span>40</span> <span>    }
</span><span>41</span>     
<span>42</span>     <span>public</span> <span>function</span><span> inSimpleUserClassPublic() {
</span><span>43</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>44</span> <span>    }
</span><span>45</span>     
<span>46</span>     <span>protected</span> <span>function</span><span> inSimpleUserClassProtected(){
</span><span>47</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>48</span> <span>    }
</span><span>49</span>     
<span>50</span>     <span>private</span> <span>function</span><span> inSimpleUserClassPrivate() {
</span><span>51</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>52</span> <span>    }
</span><span>53</span> <span>}
</span><span>54</span> 
<span>55</span> <span>class</span> adminUser <span>extends</span><span> simpleUser {
</span><span>56</span>     <span>protected</span> <span>$admin_user</span><span>;
</span><span>57</span>     <span>public</span> <span>function</span><span> __construct(){
</span><span>58</span>         <span>//</span><span>print __CLASS__." ";</span>
<span>59</span>         parent::<span>__construct();
</span><span>60</span> <span>    }
</span><span>61</span>     
<span>62</span>     <span>public</span> <span>function</span><span> inAdminUserClassPublic(){
</span><span>63</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>64</span> <span>    }
</span><span>65</span>     
<span>66</span>     <span>protected</span> <span>function</span><span> inAdminUserClassProtected(){
</span><span>67</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>68</span> <span>    }
</span><span>69</span>     
<span>70</span>     <span>private</span> <span>function</span><span> inAdminUserClassPrivate(){
</span><span>71</span>         <span>print</span> <span>__CLASS__</span>.'::'.<span>__FUNCTION__</span>." "<span>;
</span><span>72</span> <span>    }
</span><span>73</span> <span>}
</span><span>74</span> 
<span>75</span> <span>class</span> administrator <span>extends</span><span> adminUser {
</span><span>76</span>     <span>public</span> <span>function</span><span> __construct(){        
</span><span>77</span>         parent::<span>__construct();
</span><span>78</span> <span>    }
</span><span>79</span> <span>}
</span><span>80</span> 
<span>81</span> <span>/*</span><span>*
</span><span>82</span> <span> * 在类的实例中 只有公有属性和方法才可以通过实例化来调用
</span><span>83</span>  <span>*/</span>
<span>84</span> <span>$s</span> = <span>new</span><span> administrator();
</span><span>85</span> <span>print</span> '-------------------'<span>;
</span><span>86</span> <span>$s</span>-><span>show();
</span><span>87</span> ?>