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<h1 class="page__title" itemprop="headline">ServiceComb Pack 0.4.0 Cluster : 集群实现
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2 分钟 阅读
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<p>Alpha可以通过扩展部署多个实例实现高可用部署，并且通过在节点上设置启动参数 <code class="highlighter-rouge">alpha.event.scanner.enabled=false</code> 关闭一些节点后台定时执行的事务扫描，避免多个节点同时扫描事物表可能导致的性能问题。但是当启动事务扫描的进程宕机后会导致没有进程进行事务扫描，从而无法进行超时事务补偿。
在0.4.0版本中，我们通过一种基于数据库表的抢占锁机制，实现Alpha集群中主节点的动态选举，并让事务扫描方法只在主节点上执行。当主节点宕机后其他节点通过抢占的方式选出一个新的主节点，本文将介绍在0.4.0版本相关的代码实现。</p>
<h2 id="快速体验">快速体验</h2>
<p>在0.4.0版本中开启动态主节点集群模式支持只需要增加启动参数 <code class="highlighter-rouge">alpha.cluster.master.enabled=true</code></p>
<ul>
<li>启动两个节点</li>
</ul>
<div class="language-bash highlighter-rouge"><div class="highlight"><pre class="highlight"><code>java <span class="nt">-jar</span> alpha-server-0.4.0-SNAPSHOT-exec.jar <span class="se">\</span>
<span class="nt">--server</span>.port<span class="o">=</span>8090 <span class="se">\</span>
<span class="nt">--alpha</span>.server.port<span class="o">=</span>8080 <span class="se">\</span>
<span class="nt">--spring</span>.datasource.url<span class="o">=</span><span class="s2">"jdbc:postgresql://127.0.0.1:5432/saga?useSSL=false"</span> <span class="se">\</span>
<span class="nt">--spring</span>.datasource.username<span class="o">=</span>saga-user <span class="se">\</span>
<span class="nt">--spring</span>.datasource.password<span class="o">=</span>saga-password <span class="se">\</span>
<span class="nt">--alpha</span>.cluster.master.enabled<span class="o">=</span><span class="nb">true</span>
</code></pre></div></div>
<div class="language-bash highlighter-rouge"><div class="highlight"><pre class="highlight"><code>java <span class="nt">-jar</span> alpha-server-0.4.0-SNAPSHOT-exec.jar <span class="se">\</span>
<span class="nt">--server</span>.port<span class="o">=</span>8091 <span class="se">\</span>
<span class="nt">--alpha</span>.server.port<span class="o">=</span>8081 <span class="se">\</span>
<span class="nt">--spring</span>.datasource.url<span class="o">=</span><span class="s2">"jdbc:postgresql://127.0.0.1:5432/saga?useSSL=false"</span> <span class="se">\</span>
<span class="nt">--spring</span>.datasource.username<span class="o">=</span>saga-user <span class="se">\</span>
<span class="nt">--spring</span>.datasource.password<span class="o">=</span>saga-password <span class="se">\</span>
<span class="nt">--alpha</span>.cluster.master.enabled<span class="o">=</span><span class="nb">true</span>
</code></pre></div></div>
<ul>
<li>节点类型信息查看</li>
</ul>
<p>在日志中看到 <code class="highlighter-rouge">Master Node</code> 则表示这个进程是主节点</p>
<div class="language-bash highlighter-rouge"><div class="highlight"><pre class="highlight"><code>01:31:07.032 <span class="o">[</span>pool-3-thread-1] INFO org.apache.servicecomb.pack.alpha.server.cluster.master.ClusterLockService - Master Node
</code></pre></div></div>
<p>在日志中看到 <code class="highlighter-rouge">Slave Node</code> 则表示这个进程是从节点</p>
<div class="language-bash highlighter-rouge"><div class="highlight"><pre class="highlight"><code>01:31:31.059 <span class="o">[</span>pool-3-thread-1] INFO org.apache.servicecomb.pack.alpha.server.cluster.master.ClusterLockService - Slave Node
</code></pre></div></div>
<ul>
<li>节点切换</li>
</ul>
<p>当主节点进程宕后，其他从节点会采用抢占的产生一个新的主节点</p>
<h2 id="让事务扫描运行在主节点">让事务扫描运行在主节点</h2>
<p>事务扫描是通过 <code class="highlighter-rouge">EventScanner.java</code> 实现的，并且在 <code class="highlighter-rouge">AlphaConfig.java</code> 中进行初始化，可以看到在 <code class="highlighter-rouge">new EventScanner</code> 代码执行前进行了eventScannerEnabled判断，这个参数就是通过<code class="highlighter-rouge">alpha.event.scanner.enabled</code> 指定的（默认是true），然后传入了<code class="highlighter-rouge">nodeStatus</code> 对象，这个对象就记录着这个节点的状态（主节点或者从节点），后边会讲解 <code class="highlighter-rouge">nodeStatus</code> 是如何构造的。</p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Bean</span>
<span class="nc">TxConsistentService</span> <span class="nf">txConsistentService</span><span class="o">(</span>
<span class="nd">@Value</span><span class="o">(</span><span class="s">"${alpha.event.pollingInterval:500}"</span><span class="o">)</span> <span class="kt">int</span> <span class="n">eventPollingInterval</span><span class="o">,</span>
<span class="nd">@Value</span><span class="o">(</span><span class="s">"${alpha.event.scanner.enabled:true}"</span><span class="o">)</span> <span class="kt">boolean</span> <span class="n">eventScannerEnabled</span><span class="o">,</span>
<span class="nc">ScheduledExecutorService</span> <span class="n">scheduler</span><span class="o">,</span>
<span class="nc">TxEventRepository</span> <span class="n">eventRepository</span><span class="o">,</span>
<span class="nc">CommandRepository</span> <span class="n">commandRepository</span><span class="o">,</span>
<span class="nc">TxTimeoutRepository</span> <span class="n">timeoutRepository</span><span class="o">,</span>
<span class="nc">OmegaCallback</span> <span class="n">omegaCallback</span><span class="o">)</span> <span class="o">{</span>
<span class="k">if</span> <span class="o">(</span><span class="n">eventScannerEnabled</span><span class="o">)</span> <span class="o">{</span>
<span class="k">new</span> <span class="nf">EventScanner</span><span class="o">(</span><span class="n">scheduler</span><span class="o">,</span>
<span class="n">eventRepository</span><span class="o">,</span> <span class="n">commandRepository</span><span class="o">,</span> <span class="n">timeoutRepository</span><span class="o">,</span>
<span class="n">omegaCallback</span><span class="o">,</span> <span class="n">eventPollingInterval</span><span class="o">,</span> <span class="n">nodeStatus</span><span class="o">).</span><span class="na">run</span><span class="o">();</span>
<span class="no">LOG</span><span class="o">.</span><span class="na">info</span><span class="o">(</span><span class="s">"Starting the EventScanner."</span><span class="o">);</span>
<span class="o">}</span>
<span class="nc">TxConsistentService</span> <span class="n">consistentService</span> <span class="o">=</span> <span class="k">new</span> <span class="nc">TxConsistentService</span><span class="o">(</span><span class="n">eventRepository</span><span class="o">);</span>
<span class="k">return</span> <span class="n">consistentService</span><span class="o">;</span>
<span class="o">}</span>
</code></pre></div></div>
<p><code class="highlighter-rouge">EventScanner.java</code> 的 pollEvents 方法进行定时事务扫描，并使用 <code class="highlighter-rouge">nodeStatus.isMaster()</code> 判断自己是否是主节点，只有主节点才允许执行。看到这里大家应该知道 <code class="highlighter-rouge">nodeStatus.isMaster()</code> 是我们判断主节点的关键对象，那么 <code class="highlighter-rouge">NodeStatus.java</code> 是如何被创建并初始化的呢</p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">private</span> <span class="kt">void</span> <span class="nf">pollEvents</span><span class="o">()</span> <span class="o">{</span>
<span class="n">scheduler</span><span class="o">.</span><span class="na">scheduleWithFixedDelay</span><span class="o">(</span>
<span class="o">()</span> <span class="o">-&gt;</span> <span class="o">{</span>
<span class="c1">// only pull the events when working in the master mode</span>
<span class="k">if</span><span class="o">(</span><span class="n">nodeStatus</span><span class="o">.</span><span class="na">isMaster</span><span class="o">()){</span>
<span class="n">updateTimeoutStatus</span><span class="o">();</span>
<span class="n">findTimeoutEvents</span><span class="o">();</span>
<span class="n">abortTimeoutEvents</span><span class="o">();</span>
<span class="n">saveUncompensatedEventsToCommands</span><span class="o">();</span>
<span class="n">compensate</span><span class="o">();</span>
<span class="n">updateCompensatedCommands</span><span class="o">();</span>
<span class="n">deleteDuplicateSagaEndedEvents</span><span class="o">();</span>
<span class="n">updateTransactionStatus</span><span class="o">();</span>
<span class="o">}</span>
<span class="o">},</span>
<span class="mi">0</span><span class="o">,</span>
<span class="n">eventPollingInterval</span><span class="o">,</span>
<span class="no">MILLISECONDS</span><span class="o">);</span>
<span class="o">}</span>
</code></pre></div></div>
<p>我们在 <code class="highlighter-rouge">AlphaConfig.java</code> 中通过以下方式创建实例，以确保无论您是否指定了 <code class="highlighter-rouge">alpha.cluster.master.enabled</code> 参数事务扫描都可以正常工作，在这里可以看到当我们开启了集群模式后节点刚启动的时候状态是Slave，下面会说明状态是如何切换到Master的。</p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Bean</span>
<span class="nc">NodeStatus</span> <span class="nf">nodeStatus</span> <span class="o">(){</span>
<span class="k">if</span><span class="o">(</span><span class="n">masterEnabled</span><span class="o">){</span>
<span class="k">return</span> <span class="k">new</span> <span class="nf">NodeStatus</span><span class="o">(</span><span class="nc">NodeStatus</span><span class="o">.</span><span class="na">TypeEnum</span><span class="o">.</span><span class="na">SLAVE</span><span class="o">);</span>
<span class="o">}</span><span class="k">else</span><span class="o">{</span>
<span class="k">return</span> <span class="k">new</span> <span class="nf">NodeStatus</span><span class="o">(</span><span class="nc">NodeStatus</span><span class="o">.</span><span class="na">TypeEnum</span><span class="o">.</span><span class="na">MASTER</span><span class="o">);</span>
<span class="o">}</span>
<span class="o">}</span>
<span class="nd">@Autowired</span>
<span class="nc">NodeStatus</span> <span class="n">nodeStatus</span><span class="o">;</span>
</code></pre></div></div>
<p>控制节点状态切换的是 <code class="highlighter-rouge">ClusterLockService.java</code> ,这个服务会定时执行锁抢占，抢占成功后设置本节点为Master，否则为Slave</p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nd">@Autowired</span>
<span class="nc">LockProvider</span> <span class="n">lockProvider</span><span class="o">;</span>
<span class="o">...</span>
<span class="o">...</span>
<span class="nd">@Scheduled</span><span class="o">(</span><span class="n">cron</span> <span class="o">=</span> <span class="s">"0/1 * * * * ?"</span><span class="o">)</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">masterCheck</span><span class="o">()</span> <span class="o">{</span>
<span class="k">if</span> <span class="o">(</span><span class="n">applicationReady</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">locker</span> <span class="o">=</span> <span class="n">lockProvider</span><span class="o">.</span><span class="na">lock</span><span class="o">(</span><span class="k">this</span><span class="o">.</span><span class="na">getMasterLock</span><span class="o">());</span>
<span class="k">if</span> <span class="o">(</span><span class="k">this</span><span class="o">.</span><span class="na">locker</span><span class="o">.</span><span class="na">isPresent</span><span class="o">())</span> <span class="o">{</span>
<span class="k">if</span> <span class="o">(!</span><span class="k">this</span><span class="o">.</span><span class="na">locked</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">locked</span> <span class="o">=</span> <span class="kc">true</span><span class="o">;</span>
<span class="n">nodeStatus</span><span class="o">.</span><span class="na">setTypeEnum</span><span class="o">(</span><span class="nc">NodeStatus</span><span class="o">.</span><span class="na">TypeEnum</span><span class="o">.</span><span class="na">MASTER</span><span class="o">);</span>
<span class="no">LOG</span><span class="o">.</span><span class="na">info</span><span class="o">(</span><span class="s">"Master Node"</span><span class="o">);</span>
<span class="o">}</span>
<span class="c1">//Keep locked</span>
<span class="o">}</span> <span class="k">else</span> <span class="o">{</span>
<span class="k">if</span> <span class="o">(</span><span class="k">this</span><span class="o">.</span><span class="na">locked</span> <span class="o">||</span> <span class="o">!</span><span class="n">lockExecuted</span><span class="o">)</span> <span class="o">{</span>
<span class="n">locked</span> <span class="o">=</span> <span class="kc">false</span><span class="o">;</span>
<span class="n">nodeStatus</span><span class="o">.</span><span class="na">setTypeEnum</span><span class="o">(</span><span class="nc">NodeStatus</span><span class="o">.</span><span class="na">TypeEnum</span><span class="o">.</span><span class="na">SLAVE</span><span class="o">);</span>
<span class="no">LOG</span><span class="o">.</span><span class="na">info</span><span class="o">(</span><span class="s">"Slave Node"</span><span class="o">);</span>
<span class="o">}</span>
<span class="o">}</span>
<span class="n">lockExecuted</span> <span class="o">=</span> <span class="kc">true</span><span class="o">;</span>
<span class="o">}</span>
<span class="o">}</span>
</code></pre></div></div>
<h2 id="加锁服务基础类">加锁服务基础类</h2>
<p>在前边的说明中可以看到，在 <code class="highlighter-rouge">ClusterLockService.java</code> 的 <code class="highlighter-rouge">masterCheck</code> 方法中通过 <code class="highlighter-rouge">this.locker = lockProvider.lock(this.getMasterLock());</code> 获取一个锁并判断是否锁成功。</p>
<p><code class="highlighter-rouge">LockProvider.java</code> 是一个接口，目前我们提供了基于 JDBC 的实现，包结构以及类依赖关系如下：</p>
<p><img src="/assets/images/2019-04-03-servicecomb-pack-cluster/cluster-package-structure.png" alt="cluster-package-structure" /></p>
<p>依赖关系如下</p>
<p><img src="/assets/images/2019-04-03-servicecomb-pack-cluster/class-dependency-1.png" alt="class-dependency-1" /></p>
<ul>
<li>
<p>LockProvider.java</p>
<p>接口定义了锁方法 lock</p>
</li>
<li>
<p>LockProviderPersistence.java</p>
<p>接口定义了以下三个方法，作为持久化锁的接口</p>
<ul>
<li>initLock 创建锁，尝试进行锁定并返回锁定是否成功</li>
<li>updateLock 更新锁，进行再次锁定并返回是否成功（更新锁的接口设计的目的是为了非长连接锁设计，例如对于按照固定周期进行加锁的实现）</li>
<li>unLock 解锁，取消锁定</li>
</ul>
</li>
<li>
<p>AbstractLockProvider.java</p>
<p>抽象类实现了 <code class="highlighter-rouge">LockProvider.java</code> 接口的lock方法，并调用内部的 <code class="highlighter-rouge">LockProviderPersistence.java</code> 接口进行锁操作</p>
</li>
</ul>
<h2 id="加锁服务-jdbc-实现">加锁服务 JDBC 实现</h2>
<blockquote>
<p>我喜欢和你们一起跑步，一致的步伐，一样的心跳，这感觉真好，当你掉队了，我带着大家跑</p>
</blockquote>
<ul>
<li>JDBC 类关系图</li>
</ul>
<p><img src="/assets/images/2019-04-03-servicecomb-pack-cluster/class-dependency-2.png" alt="class-dependency-2" /></p>
<ul>
<li>
<p>JdbcLockPersistence.java</p>
<p><code class="highlighter-rouge">LockProviderPersistence.java</code> 接口实现，用来实现对数据库表操作</p>
</li>
<li>
<p>JdbcLockProvider.java</p>
<p>继承抽象类 <code class="highlighter-rouge">AbstractLockProvider.java</code> ，在构造函数中传入 ``LockProviderPersistence.java<code class="highlighter-rouge"> 的接口实现 </code>JdbcLockPersistence`</p>
</li>
<li>
<p>LockProviderJdbcConfiguration.java</p>
<p>锁的JDBC实例构造类</p>
</li>
<li>
<p>JPA</p>
<p>MasterLockEntityRepository.java、SpringMasterLockRepository.java、org.apache.servicecomb.pack.alpha.server.cluster.master.provider.jdbc.jpa.*</p>
</li>
<li>
<p>锁定表结构设计</p>
</li>
</ul>
<div class="language-sql highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">CREATE</span> <span class="k">TABLE</span> <span class="n">IF</span> <span class="k">NOT</span> <span class="k">EXISTS</span> <span class="n">master_lock</span> <span class="p">(</span>
<span class="n">serviceName</span> <span class="nb">varchar</span><span class="p">(</span><span class="mi">36</span><span class="p">)</span> <span class="k">not</span> <span class="k">NULL</span><span class="p">,</span>
<span class="n">expireTime</span> <span class="nb">datetime</span> <span class="k">NOT</span> <span class="k">NULL</span> <span class="k">DEFAULT</span> <span class="k">CURRENT_TIMESTAMP</span><span class="p">,</span>
<span class="n">lockedTime</span> <span class="nb">datetime</span> <span class="k">NOT</span> <span class="k">NULL</span> <span class="k">DEFAULT</span> <span class="k">CURRENT_TIMESTAMP</span><span class="p">,</span>
<span class="n">instanceId</span> <span class="nb">varchar</span><span class="p">(</span><span class="mi">255</span><span class="p">)</span> <span class="k">not</span> <span class="k">NULL</span><span class="p">,</span>
<span class="k">PRIMARY</span> <span class="k">KEY</span> <span class="p">(</span><span class="n">serviceName</span><span class="p">)</span>
<span class="p">)</span> <span class="n">ENGINE</span><span class="o">=</span><span class="n">InnoDB</span> <span class="k">DEFAULT</span> <span class="n">CHARSET</span><span class="o">=</span><span class="n">utf8</span><span class="p">;</span>
</code></pre></div></div>
<ul>
<li>serviceName 服务名，这个字段取值 <code class="highlighter-rouge">${spring.application.name}</code></li>
<li>expireTime 锁定过期时间，这个字段取值 lockedTime+5s</li>
<li>lockedTime 最近一次锁定时间</li>
<li>instanceId 集群实例ID，这个字段取值 <code class="highlighter-rouge">${alpha.server.host}]:${alpha.server.port}</code></li>
</ul>
<h2 id="加锁过程">加锁过程</h2>
<p>加锁/更新锁的过程是一个周期性重复执行的动作，步骤如下：</p>
<ul>
<li>
<p><code class="highlighter-rouge">ClusterLockService.java</code> 服务中会每秒调用一次 <code class="highlighter-rouge">LockProvider.java</code> 接口的lock方法</p>
</li>
<li>
<p><code class="highlighter-rouge">AbstractLockProvider.java</code> 抽象类中的 lock方法会尝试调用 <code class="highlighter-rouge">JdbcLockPersistence.java</code> 的 iniLock方法进行加锁，加锁的SQL实现定义在 <code class="highlighter-rouge">MasterLockEntityRepository.java</code> 中</p>
<ul>
<li>如果表为空，那么插入一条记录并返回加锁成功</li>
<li>如果表中存在serviceName字段相同的记录，则捕获异常加锁失败</li>
</ul>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code> <span class="nd">@Transactional</span>
<span class="nd">@Modifying</span>
<span class="nd">@Query</span><span class="o">(</span><span class="n">value</span> <span class="o">=</span> <span class="s">"INSERT INTO master_lock "</span>
<span class="o">+</span> <span class="s">"(serviceName, expireTime, lockedTime, instanceId) "</span>
<span class="o">+</span> <span class="s">"VALUES "</span>
<span class="o">+</span> <span class="s">"(?1, ?2, ?3, ?4)"</span><span class="o">,</span> <span class="n">nativeQuery</span> <span class="o">=</span> <span class="kc">true</span><span class="o">)</span>
<span class="kt">int</span> <span class="nf">initLock</span><span class="o">(</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"serviceName"</span><span class="o">)</span> <span class="nc">String</span> <span class="n">serviceName</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"expireTime"</span><span class="o">)</span> <span class="nc">Date</span> <span class="n">expireTime</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"lockedTime"</span><span class="o">)</span> <span class="nc">Date</span> <span class="n">lockedTime</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"instanceId"</span><span class="o">)</span> <span class="nc">String</span> <span class="n">instanceId</span><span class="o">);</span>
</code></pre></div> </div>
</li>
<li>
<p>如果 initLock加锁失败，则尝试调用 <code class="highlighter-rouge">MasterLockEntityRepository.java</code> 中的 updateLock 方法尝试更新锁</p>
<ul>
<li>表中存在的本服务记录 instanceId 与本实例 instanceId 相同，则更新成功并返回加锁成功（这个表明上一个更新周期也是本服务更新的）</li>
<li>表中存在的本服务记录 expireTime 小于当前锁定时间 ，则更新成功并返回加锁成功（表示上一个锁定周期并没有实例进行锁定更新操作）</li>
</ul>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code> <span class="nd">@Transactional</span>
<span class="nd">@Modifying</span><span class="o">(</span><span class="n">clearAutomatically</span> <span class="o">=</span> <span class="kc">true</span><span class="o">)</span>
<span class="nd">@Query</span><span class="o">(</span><span class="s">"UPDATE org.apache.servicecomb.pack.alpha.server.cluster.master.provider.jdbc.jpa.MasterLock t "</span>
<span class="o">+</span> <span class="s">"SET t.expireTime = :expireTime"</span>
<span class="o">+</span> <span class="s">",t.lockedTime = :lockedTime "</span>
<span class="o">+</span> <span class="s">",t.instanceId = :instanceId "</span>
<span class="o">+</span> <span class="s">"WHERE t.serviceName = :serviceName AND (t.expireTime &lt;= :lockedTime OR t.instanceId = :instanceId)"</span><span class="o">)</span>
<span class="kt">int</span> <span class="nf">updateLock</span><span class="o">(</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"serviceName"</span><span class="o">)</span> <span class="nc">String</span> <span class="n">serviceName</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"lockedTime"</span><span class="o">)</span> <span class="nc">Date</span> <span class="n">lockedTime</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"expireTime"</span><span class="o">)</span> <span class="nc">Date</span> <span class="n">expireTime</span><span class="o">,</span>
<span class="nd">@Param</span><span class="o">(</span><span class="s">"instanceId"</span><span class="o">)</span> <span class="nc">String</span> <span class="n">instanceId</span><span class="o">);</span>
</code></pre></div> </div>
</li>
<li>
<p>释放锁 unLock</p>
<p>保留接口，用于扩展其他锁定方式</p>
</li>
</ul>
<h2 id="锁的其他实现">锁的其他实现</h2>
<p>可以通过 <code class="highlighter-rouge">LockProvider.java</code> 和 <code class="highlighter-rouge">LockProviderPersistence.java</code> 接口实现其他方式的锁，例如zookeeper，redis等</p>
<h2 id="注意">注意</h2>
<ul>
<li>
<p>基于数据库表的方式需要集群中多个节点的服务器时钟同步</p>
</li>
<li>
<p>基于 MySQL 数据库时需要配置正确的时区，例如：<code class="highlighter-rouge">serverTimezone=GMT%2b8</code></p>
</li>
</ul>
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success: function (data) {
$('#comment-form-submit').html('已提交');
$('.page__comments-form .js-notice').removeClass('notice--danger');
$('.page__comments-form .js-notice').addClass('notice--success');
showAlert('感谢您的评论！被批准后它会立即在此站点展示。');
},
error: function (err) {
console.log(err);
$('#comment-form-submit').html('提交评论');
$('.page__comments-form .js-notice').removeClass('notice--success');
$('.page__comments-form .js-notice').addClass('notice--danger');
showAlert('很抱歉，您的提交存在错误。请确保所有必填字段都已填写正确，然后再试一次。');
$(form).removeClass('disabled');
}
});
return false;
});
function showAlert(message) {
$('.page__comments-form .js-notice').removeClass('hidden');
$('.page__comments-form .js-notice-text').html(message);
}
})(jQuery);
</script>
</body>
</html>