PDO和訊息佇列的一點個人理解

　　什麼是訊息佇列，百度百科說，···訊息隊列····是在訊息的傳輸過程中保存訊息的容器。

　　看著網上林林總總的文章，都說是為了應對高並發，處理數據量超級大的一種數據容器，也可以說是利用各種方式，先把數據存儲在一個···容器·····中，然後，再慢慢從這個容器中取得數據，實現·····非同步操作資料庫·····的方式，以便降低資料庫的壓力。

　　不管訊息隊列是什麼，個人姑且認為它就是一種儲存資料的···容器···，就這麼簡單明了，呵呵，因為本人對訊息隊列這東西研究的比較膚淺。

　　不過，在這裡，我還是要賣弄一下一個個人的小實驗代碼，呵呵，假若下面的東西與消息隊列相離太遠，那麼請看官可別見怪哦，因為我上面已經聲明的很清楚了，本人對這東西還是不甚了解，只不過是工作之餘賣弄一下'文采'而已，所以，假如真有誤解消息隊列這個東西，我只能說聲，請你指正我的錯誤，讓筆者迷途知返。

　　先給出連接mysql資料庫設定檔mysql.ini的內容：

<span style="color: #800000; font-weight: bold">[</span><span style="color: #800000">database</span><span style="color: #800000; font-weight: bold">]</span><span style="color: #000000">
driver </span>=<span style="color: #000000"> mysql
host </span>= 127.0.0.1<span style="color: #000000">
port </span>= 3306<span style="color: #000000">
dbname </span>=<span style="color: #000000"> mysql
username </span>=<span style="color: #000000"> root
password </span>= 1234
<span style="color: #800000; font-weight: bold">[</span><span style="color: #800000">options</span><span style="color: #800000; font-weight: bold">]</span><span style="color: #000000">
PDO::MYSQL_ATTR_INIT_COMMAND </span>= set names utf8

　　資料表檔案queue.sql的內容：

<span style="color: #008080">--</span><span style="color: #008080"> 消息队列测试</span><span style="color: #008080">
--</span><span style="color: #008080"> 商品表</span>
<span style="color: #0000ff">create</span> <span style="color: #0000ff">table</span><span style="color: #000000"> goods(
id </span><span style="color: #0000ff">int</span> unsigned <span style="color: #0000ff">primary</span> <span style="color: #0000ff">key</span><span style="color: #000000"> auto_increment,
goodsname </span><span style="color: #0000ff">varchar</span>(<span style="color: #800000; font-weight: bold">40</span>) <span style="color: #808080">not</span> <span style="color: #0000ff">null</span> comment <span style="color: #ff0000">'</span><span style="color: #ff0000">商品名</span><span style="color: #ff0000">'</span><span style="color: #000000">,
price </span><span style="color: #0000ff">decimal</span>(<span style="color: #800000; font-weight: bold">9</span>,<span style="color: #800000; font-weight: bold">2</span>) <span style="color: #808080">not</span> <span style="color: #0000ff">null</span> comment <span style="color: #ff0000">'</span><span style="color: #ff0000">价格</span><span style="color: #ff0000">'</span><span style="color: #000000">,
category_id </span><span style="color: #0000ff">tinyint</span> unsigned <span style="color: #808080">not</span> <span style="color: #0000ff">null</span> comment <span style="color: #ff0000">'</span><span style="color: #ff0000">商品类别id</span><span style="color: #ff0000">'</span><span style="color: #000000">,
sort </span><span style="color: #0000ff">tinyint</span> comment <span style="color: #ff0000">'</span><span style="color: #ff0000">商品排序</span><span style="color: #ff0000">'</span><span style="color: #000000">,
description </span><span style="color: #0000ff">varchar</span>(<span style="color: #800000; font-weight: bold">255</span>) comment <span style="color: #ff0000">'</span><span style="color: #ff0000">商品描述</span><span style="color: #ff0000">'</span><span style="color: #000000">,
remark </span><span style="color: #0000ff">varchar</span>(<span style="color: #800000; font-weight: bold">255</span>) comment <span style="color: #ff0000">'</span><span style="color: #ff0000">备注</span><span style="color: #ff0000">'</span><span style="color: #000000">
)engine InnoDB </span><span style="color: #0000ff">default</span> charset<span style="color: #808080">=</span><span style="color: #000000">utf8;
</span><span style="color: #0000ff">insert</span> <span style="color: #0000ff">into</span> goods <span style="color: #0000ff">values</span>(<span style="color: #0000ff">default</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">iPhone5s</span><span style="color: #ff0000">'</span>,<span style="color: #800000; font-weight: bold">5999</span>,<span style="color: #800000; font-weight: bold">1</span>,<span style="color: #800000; font-weight: bold">1</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">美国入口贵重电子产品</span><span style="color: #ff0000">'</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">请多多销售</span><span style="color: #ff0000">'</span>),(<span style="color: #0000ff">default</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">宏基手提电脑1</span><span style="color: #ff0000">'</span>,<span style="color: #800000; font-weight: bold">4888</span>,<span style="color: #800000; font-weight: bold">3</span>,<span style="color: #800000; font-weight: bold">1</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">价格划算好电脑</span><span style="color: #ff0000">'</span>,<span style="color: #0000ff">null</span>),(<span style="color: #0000ff">default</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">f-30绒衣</span><span style="color: #ff0000">'</span>,<span style="color: #800000; font-weight: bold">200</span>,<span style="color: #800000; font-weight: bold">2</span>,<span style="color: #800000; font-weight: bold">1</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">以纯白色厚皮羽绒服</span><span style="color: #ff0000">'</span>,<span style="color: #0000ff">null</span>),(<span style="color: #0000ff">default</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">n-100鞋子</span><span style="color: #ff0000">'</span>,<span style="color: #800000; font-weight: bold">300</span>,<span style="color: #800000; font-weight: bold">4</span>,<span style="color: #800000; font-weight: bold">1</span>,<span style="color: #ff0000">'</span><span style="color: #ff0000">Nick品牌</span><span style="color: #ff0000">'</span>,<span style="color: #0000ff">null</span>);

　　以下是簡單的訊息佇列實作PDO商品入庫的程式碼：

　　鄭重提醒：請認真看我的註釋，請認真看我的註釋，請認真看我的註釋。重要的訊息要說三遍，呵呵！

<?<span style="color: #000000">php
namespace Home;
</span><span style="color: #008080">header</span>('content-type:text/html;charset=utf-8;'<span style="color: #000000">);
</span><span style="color: #008000">//</span><span style="color: #008000">引入PDO类</span>
<span style="color: #0000ff">use</span><span style="color: #000000"> \PDO;
</span><span style="color: #0000ff">use</span><span style="color: #000000"> \PDOStatement;
</span><span style="color: #0000ff">use</span><span style="color: #000000"> \PDOException;
</span><span style="color: #008000">/*</span><span style="color: #008000">简单消息队列</span><span style="color: #008000">*/</span>
<span style="color: #0000ff">class</span><span style="color: #000000"> Queue{
    </span><span style="color: #008000">//</span><span style="color: #008000">容器可以是私有，最好是公有</span>
    <span style="color: #0000ff">static</span> <span style="color: #0000ff">public</span> <span style="color: #800080">$container</span>=<span style="color: #0000ff">array</span><span style="color: #000000">();
    </span><span style="color: #008000">//</span><span style="color: #008000">把PDO对象存放到属性中是为了跨方法使用</span>
    <span style="color: #0000ff">static</span> <span style="color: #0000ff">private</span> <span style="color: #800080">$pdo</span><span style="color: #000000">;
    </span><span style="color: #008000">//</span><span style="color: #008000">构造函数实现初始化PDO连接数据库</span>
    <span style="color: #0000ff">public</span> <span style="color: #0000ff">function</span> __construct(<span style="color: #800080">$file</span> = './mysql.ini'){<span style="color: #008000">//</span><span style="color: #008000">mysql数据库的配置文件，./mysql.ini与这个类是同一个目录
        //parse_ini_file函数作用，解析并获取ini文件的参数，加true是二维数组</span>
        <span style="color: #800080">$dbini</span>        = <span style="color: #008080">parse_ini_file</span>(<span style="color: #800080">$file</span>,<span style="color: #0000ff">true</span><span style="color: #000000">);
        </span><span style="color: #800080">$driver</span>        = <span style="color: #800080">$dbini</span>['database']['driver'<span style="color: #000000">];
        </span><span style="color: #008000">//</span><span style="color: #008000">这里的数据库是mysql的总数据库</span>
        <span style="color: #800080">$dbname</span>        = <span style="color: #800080">$dbini</span>['database']['dbname'<span style="color: #000000">];
        </span><span style="color: #800080">$host</span>        = <span style="color: #800080">$dbini</span>['database']['host'<span style="color: #000000">];
        </span><span style="color: #800080">$port</span>        = <span style="color: #800080">$dbini</span>['database']['port'<span style="color: #000000">];
        </span><span style="color: #008000">//</span><span style="color: #008000">构造PDO连接数据库的第一个参数，这个参数这么设置纯属是PDO类的语法，不懂的可以百度一下，这里就不做详解了</span>
        <span style="color: #800080">$dsn</span> = <span style="color: #800080">$driver</span>.':'.'dbname='.<span style="color: #800080">$dbname</span>.';host='.<span style="color: #800080">$host</span>.';port='.<span style="color: #800080">$port</span><span style="color: #000000">;
        </span><span style="color: #008000">//</span><span style="color: #008000">其他连接数据库参数</span>
        <span style="color: #800080">$username</span>    = <span style="color: #800080">$dbini</span>['database']['username'<span style="color: #000000">];
        </span><span style="color: #800080">$password</span>    = <span style="color: #800080">$dbini</span>['database']['password'<span style="color: #000000">];
        </span><span style="color: #800080">$options</span>    = <span style="color: #800080">$dbini</span>['options'];<span style="color: #008000">//</span><span style="color: #008000">初始化设置PDO选项</span>
        <span style="color: #0000ff">try</span><span style="color: #000000">{
            self</span>::<span style="color: #800080">$pdo</span> = <span style="color: #0000ff">new</span> PDO(<span style="color: #800080">$dsn</span>,<span style="color: #800080">$username</span>,<span style="color: #800080">$password</span>,<span style="color: #800080">$options</span><span style="color: #000000">);
            </span><span style="color: #008000">//</span><span style="color: #008000">设置PDO属性。抛出错误报告</span>
            self::<span style="color: #800080">$pdo</span>->setAttribute(PDO::ATTR_ERRMODE,PDO::<span style="color: #000000">ERRMODE_EXCEPTION);
            </span><span style="color: #0000ff">try</span><span style="color: #000000">{
                </span><span style="color: #008000">//</span><span style="color: #008000">选择商品数据表所在的数据库</span>
                self::<span style="color: #800080">$pdo</span>-><span style="color: #008080">exec</span>('use queue'<span style="color: #000000">);
            }</span><span style="color: #0000ff">catch</span>(PDOException <span style="color: #800080">$e</span><span style="color: #000000">){
                </span><span style="color: #0000ff">echo</span> <span style="color: #800080">$e</span>-><span style="color: #000000">getMessage();
            }
        }</span><span style="color: #0000ff">catch</span>(PDOException <span style="color: #800080">$e</span><span style="color: #000000">){
            </span><span style="color: #0000ff">echo</span> <span style="color: #800080">$e</span>-><span style="color: #000000">getMessage();
        }
    }
    </span><span style="color: #008000">/*</span><span style="color: #008000">
    *入列
    *$data数组
    *成功返回1，失败返回false，或者null
    </span><span style="color: #008000">*/</span>
    <span style="color: #0000ff">public</span> <span style="color: #0000ff">function</span> _unshift(<span style="color: #800080">$data</span> =<span style="color: #0000ff">array</span><span style="color: #000000">()){
        </span><span style="color: #0000ff">if</span>(!<span style="color: #008080">is_array</span>(<span style="color: #800080">$data</span>) || <span style="color: #0000ff">empty</span>(<span style="color: #800080">$data</span>)){<span style="color: #0000ff">return</span> <span style="color: #0000ff">false</span><span style="color: #000000">;}
        </span><span style="color: #800080">$sql</span> = 'default'<span style="color: #000000">;
        </span><span style="color: #0000ff">foreach</span>(<span style="color: #800080">$data</span> <span style="color: #0000ff">as</span> <span style="color: #800080">$k</span>=><span style="color: #800080">$v</span><span style="color: #000000">){
            </span><span style="color: #800080">$sql</span> .= ',"'.<span style="color: #800080">$v</span>.'"'<span style="color: #000000">;
        }
        </span><span style="color: #008000">//</span><span style="color: #008000">把$data转为sql语句，添加到队列容器contain中</span>
        <span style="color: #800080">$sql</span> = 'insert into goods values('.<span style="color: #800080">$sql</span>.')'<span style="color: #000000">;
        </span><span style="color: #0000ff">return</span> @<span style="color: #008080">array_unshift</span>(self::<span style="color: #800080">$container</span>,<span style="color: #800080">$sql</span><span style="color: #000000">);
    }
    </span><span style="color: #008000">/*</span><span style="color: #008000">
    *出列
    *成功返回最后插入的数据id
    *失败返回失败信息
    </span><span style="color: #008000">*/</span>
    <span style="color: #0000ff">private</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">function</span><span style="color: #000000"> _pop(){
        </span><span style="color: #0000ff">try</span>{<span style="color: #008000">//</span><span style="color: #008000">获取尾部的sql语句，出列</span>
            <span style="color: #800080">$sql</span> = <span style="color: #008080">array_pop</span>(self::<span style="color: #800080">$container</span><span style="color: #000000">);
            self</span>::<span style="color: #800080">$pdo</span>-><span style="color: #008080">exec</span>(<span style="color: #800080">$sql</span><span style="color: #000000">);
            </span><span style="color: #008000">//</span><span style="color: #008000">把剩余的容器值赋给中间变量</span>
            <span style="color: #800080">$middle</span> = self::<span style="color: #800080">$container</span><span style="color: #000000">;
            </span><span style="color: #008000">//</span><span style="color: #008000">判断中间变量是否为空，不为空则继续获取容器尾部的数据，继续出列</span>
            <span style="color: #0000ff">while</span>(<span style="color: #800080">$middle</span><span style="color: #000000">){
                </span><span style="color: #800080">$sql</span> = <span style="color: #008080">array_pop</span>(<span style="color: #800080">$middle</span><span style="color: #000000">);
                self</span>::<span style="color: #800080">$pdo</span>-><span style="color: #008080">exec</span>(<span style="color: #800080">$sql</span><span style="color: #000000">);
                </span><span style="color: #008000">//</span><span style="color: #008000">把数据再转给容器，也就是转给while循环外面的$middle，这样才能实现循环，让容器里面的数据全部出列，插入到数据库中</span>
                self::<span style="color: #800080">$container</span> = <span style="color: #800080">$middle</span><span style="color: #000000">;
            }
            </span><span style="color: #008000">//</span><span style="color: #008000">返回的是，最后插入的id，失败是null</span>
            <span style="color: #0000ff">return</span> self::<span style="color: #800080">$pdo</span>-><span style="color: #000000">lastInsertId();

            }</span><span style="color: #0000ff">catch</span>(PDOException <span style="color: #800080">$e</span><span style="color: #000000">){
                </span><span style="color: #0000ff">return</span> <span style="color: #800080">$e</span>-><span style="color: #000000">getMessage();
            }
    }
    </span><span style="color: #008000">//</span><span style="color: #008000">析构函数，对象回收时调用，通过它实现自动让容器数据入库</span>
    <span style="color: #0000ff">public</span> <span style="color: #0000ff">function</span><span style="color: #000000"> __destruct(){
        </span><span style="color: #008000">//</span><span style="color: #008000">当对象被回收时，判断容器是否存在消息，假如存在，则调用_pop方法，把消息出列</span>
        <span style="color: #0000ff">if</span>(self::<span style="color: #800080">$container</span><span style="color: #000000">){
            self</span>::<span style="color: #000000">_pop();
        }
    }
}</span>

　　下面是同一級目錄下呼叫這個類別的檔案的內容，當然，你也可以在上面那個queue類別的下面呼叫_unshift方法實作訊息佇列的操作

<?<span style="color: #000000">php
</span><span style="color: #0000ff">include</span> './queue.php'<span style="color: #000000">;
</span><span style="color: #0000ff">use</span> Home\Queue;<span style="color: #008000">//</span><span style="color: #008000">引入命名空间的Queue类</span>
<span style="color: #800080">$ob</span> = <span style="color: #0000ff">new</span><span style="color: #000000"> Queue;
</span><span style="color: #008000">//</span><span style="color: #008000">消息入列</span>
<span style="color: #800080">$ob</span>->_unshift(<span style="color: #0000ff">array</span>('goodsname'=>'vivo手机8888','price'=>1120,'category_id'=>1,'sort'=>1,'description'=>'vivo品牌','remark'=>'好用'<span style="color: #000000">));
</span><span style="color: #800080">$ob</span>->_unshift(<span style="color: #0000ff">array</span>('goodsname'=>'小米手机888','price'=>1998,'category_id'=>1,'sort'=>1,'description'=>'小米品牌手机','remark'=>'国产好货'<span style="color: #000000">));
</span><span style="color: #008000">//</span><span style="color: #008000">之所以打印出来，完成是为了看看效果，至于，有没有实现商品入库，你得去看看你的数据库了，呵呵</span>
<span style="color: #008080">var_dump</span>(Queue::<span style="color: #800080">$container</span>);