Xmemcached与Spring 3.0的集成

昨天收到一个xmc的issue报告，大概的意思是将 Xmemcached 与spring 2.5集成没有任何问题，但是将spring升级到3.0就会抛出一个异常，并且spring容器无法正常启动，异常信息类似“ Couldn't find a destroy method named 'shutdown' on bean XMemcachedClientFactoryBean”。更详细的情况可以看这里，这是这位朋友分析的结果，简单来说就是spring 3.0对于查找destroy method为空的情况处理不同了，过去是打个日志，现在是抛出一个异常。
   问题说完，这里主要是介绍下这个问题的解决方式，事实上Xmemcached有一个没有被文档化的Spring配置方式，没有写入文档的主要考虑是以为wiki介绍的第一种方式已经足够，而builder的方式相对繁琐一些。通过XmemcachedClientBuilder的这个factory bean的factory-method，也就是build方法来构建MemcachedClient，这就可以绕开spring 3.0的这个问题。一个示范配置如下：

< bean  name ="memcachedClientBuilder"  class ="net.rubyeye.xmemcached.XMemcachedClientBuilder" >
         < constructor-arg >
             < list >
                 < bean  class ="java.net.InetSocketAddress" >
                     < constructor-arg >
                         < value >localhost </ value >
                     </ constructor-arg >
                     < constructor-arg >
                         < value >12000 </ value >
                     </ constructor-arg >
                 </ bean >
             </ list >
         </ constructor-arg >
     </ bean >
     < bean  name ="memcachedClient"  factory-bean ="memcachedClientBuilder"
        factory-method ="build"  destroy-method ="shutdown"   />

   memcachedClientBuilder作为一个factory-bean，接受一个InetSocketAddress列表作为构造函数传入，最后MemcachedClient就可以通过factory-method——也就是build方法创建了。

   多个节点情况下，可能你想设置权重，那么传入memcachedClientBuilder的第二个构造函数 参数权重数组 即可：

< bean  name ="memcachedClientBuilder"  class ="net.rubyeye.xmemcached.XMemcachedClientBuilder" >
         < constructor-arg >
             < list >
                 < bean  class ="java.net.InetSocketAddress" >
                     < constructor-arg >
                         < value >localhost </ value >
                     </ constructor-arg >
                     < constructor-arg >
                         < value >12000 </ value >
                     </ constructor-arg >
                 </ bean >
                 < bean  class ="java.net.InetSocketAddress" >
                     < constructor-arg >
                         < value >localhost </ value >
                     </ constructor-arg >
                     < constructor-arg >
                         < value >12001 </ value >
                     </ constructor-arg >
                 </ bean >
             </ list >
         </ constructor-arg >
         < constructor-arg >
             < list >
                 < value >1 </ value >
                 < value >2 </ value >
             </ list >
         </ constructor-arg >
     </ bean >
     < bean  name ="memcachedClient"  factory-bean ="memcachedClientBuilder"
        factory-method ="build"  destroy-method ="shutdown"   />

上面的例子将localhost:12000的权重设置为1，而localhost:12001的权重设置为2。除了这些配置外，XmemcachedClientBuilder还有其他选项，如配置一致性哈希算法、连接池等，完整的配置例子如下：

< bean  name ="memcachedClientBuilder"  class ="net.rubyeye.xmemcached.XMemcachedClientBuilder" >
                 <!--  XMemcachedClientBuilder have two arguments.First is server list,and second is weights array.  -->
                 < constructor-arg >
                         < list >
                                 < bean  class ="java.net.InetSocketAddress" >
                                         < constructor-arg >
                                                 < value >localhost </ value >
                                         </ constructor-arg >
                                         < constructor-arg >
                                                 < value >12000 </ value >
                                         </ constructor-arg >
                                 </ bean >
                                 < bean  class ="java.net.InetSocketAddress" >
                                         < constructor-arg >
                                                 < value >localhost </ value >
                                         </ constructor-arg >
                                         < constructor-arg >
                                                 < value >12001 </ value >
                                         </ constructor-arg >
                                 </ bean >
                         </ list >
                 </ constructor-arg >
                 < constructor-arg >
                         < list >
                                 < value >1 </ value >
                                 < value >2 </ value >
                         </ list >
                 </ constructor-arg >
                 < property  name ="connectionPoolSize"  value ="2" ></ property >
                 < property  name ="commandFactory" >
                         < bean  class ="net.rubyeye.xmemcached.command.TextCommandFactory" ></ bean >
                 </ property >
                 < property  name ="sessionLocator" >
                         < bean  class ="net.rubyeye.xmemcached.impl.KetamaMemcachedSessionLocator" ></ bean >
                 </ property >
                 < property  name ="transcoder" >
                         < bean  class ="net.rubyeye.xmemcached.transcoders.SerializingTranscoder"   />
                 </ property >
         </ bean >
         <!--  Use factory bean to build memcached client  -->
         < bean  name ="memcachedClient"  factory-bean ="memcachedClientBuilder"
                factory-method ="build"  destroy-method ="shutdown" />