[mysqli :: init 및 mysqli :: 데이터베이스 연결 작업 프로세스를 단순화하기 위해 기능을 결합하는 방법

gitbox 2025-06-13

1. mysqli :: init和mysqli :: connect的基本概念

mysqli :: init

mysqli :: init是 mysqli 扩展中一个非常重要的方法, 它用于初始化一个mysqli对象。该方法不需要传入任何参数, 返回一个新的mysqli对象, 之后可以使用该对象调用其他的 mysqli 方法。

 <span><span><span class="hljs-variable">$mysqli</span></span><span> = </span><span><span class="hljs-title function_ invoke__">mysqli_init</span></span><span>();
</span></span>

mysqli :: connect

mysqli :: connect是mysqli类的一个实例方法类的一个实例方法, 专门用于建立与 mysql 数据库的连接。它需要传入数据库主机、用户名、密码和数据库名等参数。如果连接成功, 它将返回一个有效的mysqli对象, 否则返回false 。

 <span><span><span class="hljs-variable">$mysqli</span></span><span>-&gt;</span><span><span class="hljs-title function_ invoke__">connect</span></span><span>(</span><span><span class="hljs-string">'localhost'</span></span><span>, </span><span><span class="hljs-string">'user'</span></span><span>, </span><span><span class="hljs-string">'password'</span></span><span>, </span><span><span class="hljs-string">'database'</span></span><span>);
</span></span>

2. 使用mysqli :: init和mysqli :: connect简化连接过程

通过结合这两个函数通过结合这两个函数, 我们可以将数据库连接过程封装到一个函数中, 从而实现代码的复用和简洁。下面是如何将这两个函数结合使用的示例。

示例：创建一个数据库连接类

<span><span><span class="hljs-class"><span class="hljs-keyword">class</span></span></span><span> </span><span><span class="hljs-title">Database</span></span><span> {
    </span><span><span class="hljs-keyword">private</span></span><span> </span><span><span class="hljs-variable">$mysqli</span></span><span>;

    </span><span><span class="hljs-keyword">public</span></span><span> </span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">__construct</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$host</span></span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>) {
        </span><span><span class="hljs-comment">// &#20351;&#29992; mysqli::init &#21021;&#22987;&#21270;&#23545;&#35937;</span></span><span>
        </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli = </span><span><span class="hljs-title function_ invoke__">mysqli_init</span></span><span>();
        
        </span><span><span class="hljs-comment">// &#20351;&#29992; mysqli::connect &#24314;&#31435;&#36830;&#25509;</span></span><span>
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;</span><span><span class="hljs-title function_ invoke__">connect</span></span><span>(</span><span><span class="hljs-variable">$host</span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>)) {
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"&#25968;&#25454;&#24211;&#36830;&#25509;&#25104;&#21151;&#65281;"</span></span><span>;
        } </span><span><span class="hljs-keyword">else</span></span><span> {
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"&#25968;&#25454;&#24211;&#36830;&#25509;&#22833;&#36133;&#65306;"</span></span><span> . </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;connect_error;
        }
    }

    </span><span><span class="hljs-keyword">public</span></span><span> </span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">getConnection</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
        </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli;
    }
}
</span></span>

在上面的示例中, 我们将mysqli :: init和mysqli :: connect结合在一个数据库类中, 这样我们就可以通过创建类的实例来进行数据库连接操作。这个方式不仅简化了代码, 还可以更方便地进行错误处理和扩展。

使用类进行连接

<span><span><span class="hljs-variable">$db</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title class_">Database</span></span><span>(</span><span><span class="hljs-string">'localhost'</span></span><span>, </span><span><span class="hljs-string">'root'</span></span><span>, </span><span><span class="hljs-string">'password'</span></span><span>, </span><span><span class="hljs-string">'test_db'</span></span><span>);
</span></span>

3. 优化数据库连接过程

虽然上述代码已经简化了数据库连接的流程虽然上述代码已经简化了数据库连接的流程, 但在实际开发中但在实际开发中, 我们常常需要避免每次都重新连接数据库。为了优化数据库连接, 可以使用单例模式, 确保数据库连接只创建一次。确保数据库连接只创建一次。

示例：数据库连接类使用单例模式

<span><span><span class="hljs-class"><span class="hljs-keyword">class</span></span></span><span> </span><span><span class="hljs-title">Database</span></span><span> {
    </span><span><span class="hljs-keyword">private</span></span><span> </span><span><span class="hljs-variable">$mysqli</span></span><span>;
    </span><span><span class="hljs-keyword">private</span></span><span> </span><span><span class="hljs-built_in">static</span></span><span> </span><span><span class="hljs-variable">$instance</span></span><span> = </span><span><span class="hljs-literal">null</span></span><span>;

    </span><span><span class="hljs-keyword">private</span></span><span> </span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">__construct</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$host</span></span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>) {
        </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli = </span><span><span class="hljs-title function_ invoke__">mysqli_init</span></span><span>();
        </span><span><span class="hljs-keyword">if</span></span><span> (!</span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;</span><span><span class="hljs-title function_ invoke__">connect</span></span><span>(</span><span><span class="hljs-variable">$host</span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>)) {
            </span><span><span class="hljs-keyword">die</span></span><span>(</span><span><span class="hljs-string">'&#25968;&#25454;&#24211;&#36830;&#25509;&#22833;&#36133;: '</span></span><span> . </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;connect_error);
        }
    }

    </span><span><span class="hljs-keyword">public</span></span><span> </span><span><span class="hljs-built_in">static</span></span><span> </span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">getInstance</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$host</span></span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>) {
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-built_in">self</span></span><span>::</span><span><span class="hljs-variable">$instance</span></span><span> == </span><span><span class="hljs-literal">null</span></span><span>) {
            </span><span><span class="hljs-built_in">self</span></span><span>::</span><span><span class="hljs-variable">$instance</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title class_">Database</span></span><span>(</span><span><span class="hljs-variable">$host</span></span><span>, </span><span><span class="hljs-variable">$user</span></span><span>, </span><span><span class="hljs-variable">$password</span></span><span>, </span><span><span class="hljs-variable">$dbname</span></span><span>);
        }
        </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-built_in">self</span></span><span>::</span><span><span class="hljs-variable">$instance</span></span><span>;
    }

    </span><span><span class="hljs-keyword">public</span></span><span> </span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">getConnection</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
        </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli;
    }
}
</span></span>

通过这种方式通过这种方式, 我们确保了每次访问数据库时都返回同一个mysqli实例, 避免了多次连接数据库的开销, 提高了性能。提高了性能。

使用单例模式获取数据库连接

<span><span><span class="hljs-variable">$db</span></span><span> = </span><span><span class="hljs-title class_">Database</span></span><span>::</span><span><span class="hljs-title function_ invoke__">getInstance</span></span><span>(</span><span><span class="hljs-string">'localhost'</span></span><span>, </span><span><span class="hljs-string">'root'</span></span><span>, </span><span><span class="hljs-string">'password'</span></span><span>, </span><span><span class="hljs-string">'test_db'</span></span><span>);
</span></span>

Database :: getInstance ()方法时方法时, 都会返回同一个数据库连接实例, 这样在项目中可以更高效地管理数据库连接。

4. 处理数据库连接错误

在进行数据库连接时, 我们经常需要捕获并处理连接错误。可以通过mysqli :: connect_error属性来获取错误信息, 并根据错误类型采取相应的措施。

 <span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;connect_error) {
    </span><span><span class="hljs-keyword">die</span></span><span>(</span><span><span class="hljs-string">'&#25968;&#25454;&#24211;&#36830;&#25509;&#22833;&#36133;: '</span></span><span> . </span><span><span class="hljs-variable language_">$this</span></span><span>-&gt;mysqli-&gt;connect_error);
}
</span></span>

通过这种方式通过这种方式, 能够确保当连接失败时能够确保当连接失败时, 能清晰地输出错误信息, 帮助开发人员迅速定位问题。

5. 总结

mysqli :: init和mysqli :: connect方法, 我们可以简化数据库连接的过程, 减少重复代码的编写。封装成类或使用单例模式, 能够使数据库连接更加高效、简洁, 同时提高代码的可维护性。理解和灵活使用这些方法同时提高代码的可维护性。理解和灵活使用这些方法, 将对你的 php 开发工作大有裨益。

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