征服 Mongodb 之 主从复制&集群复制

今天研究Memcached的Java的Client，使用XMemcached 1.3.5，做个简单的测试，并介绍如何与Spring集成。 

相关链接： 
Memcached笔记——（一）安装&常规错误&监控 
Memcached笔记——（二）XMemcached&Spring集成 
Memcached笔记——（三）Memcached使用总结 
Memcached笔记——（四）应对高并发攻击 


一、Memcached Client简要介绍 
Memcached Client目前有3种： 

• Memcached Client for Java
• SpyMemcached
• XMemcached

这三种Client一直存在各种争议： 

• Memcached Client for Java 比 SpyMemcached更稳定、更早、更广泛；
• SpyMemcached 比 Memcached Client for Java更高效；
• XMemcached 比 SpyMemcache并发效果更好。

用数据来说话，参考官方性能对比： 
Memcached Client for Java：https://github.com/gwhalin/Memcached-Java-Client/wiki/PERFORMANCE 
XMemcached：http://xmemcached.googlecode.com/svn/trunk/benchmark/benchmark.html 

二、XMemcached特性 
XMemcached特性： 

• 高性能
• 支持完整的memcached文本协议,二进制协议。
• 支持JMX，可以通过MBean调整性能参数、动态添加/移除server、查看统计等。
• 支持客户端统计
• 支持memcached节点的动态增减。
• 支持memcached分布:余数分布和一致性哈希分布。
• 更多的性能调整选项。

此外，XMemcached更容易与Spring集成。而且，属于中国原创！  

三、XMemcached简单实现 

MemcachedClientBuilder是MemcachedClient核心接口，用来控制Client的构建（build()方法）和关闭（shutdown()方法）。 
XMemcachedClientBuilder一般通过构造方法配置地址列表，通常还要配置权重，代码如下： 

Java代码  

1. public XMemcachedClientBuilder(List<InetSocketAddress> addressList) {  
2.     if (addressList != null) {  
3.         for (InetSocketAddress addr : addressList) {  
4.             this.addressMap.put(addr, null);  
5.         }  
6.     }  
7. }  
8.   
9. public XMemcachedClientBuilder(List<InetSocketAddress> addressList,  
10.         int[] weights) {  
11.     if (addressList != null) {  
12.         for (InetSocketAddress addr : addressList) {  
13.             this.addressMap.put(addr, null);  
14.         }  
15.     }  
16.     this.weights = weights;  
17. }  

不过这哥们如果用this()可以省点代码， 还有给加点注释吧！ 
此外，还需要设置连接池大小，使用二进制协议/文本协议等。 
通过build()方法获得MemcachedClient 
然后就可以通过Memcached进行set、get、replace、delete等Memcached操作了！ 
上代码： 

Java代码  

1. import static junit.framework.Assert.*;  
2.   
3. import java.io.IOException;  
4. import java.util.concurrent.TimeoutException;  
5.   
6. import net.rubyeye.xmemcached.MemcachedClient;  
7. import net.rubyeye.xmemcached.MemcachedClientBuilder;  
8. import net.rubyeye.xmemcached.XMemcachedClientBuilder;  
9. import net.rubyeye.xmemcached.command.BinaryCommandFactory;  
10. import net.rubyeye.xmemcached.exception.MemcachedException;  
11. import net.rubyeye.xmemcached.utils.AddrUtil;  
12.   
13. import org.junit.Test;  
14.   
15. public class MemcachedClientTest {  
16.     @Test  
17.     public void test() {  
18.         MemcachedClientBuilder builder = new XMemcachedClientBuilder(  
19.                 AddrUtil.getAddresses("10.11.155.26:11211 10.11.155.41:11211 10.10.76.31:11211 10.10.76.35:11211"),  
20.                 new int[] { 1, 1, 1, 1 });  
21.           
22.         // 设置连接池大小，即客户端个数  
23.         builder.setConnectionPoolSize(50);  
24.   
25.         // 宕机报警  
26.         builder.setFailureMode(true);  
27.   
28.         // 使用二进制文件  
29.         builder.setCommandFactory(new BinaryCommandFactory());  
30.   
31.         MemcachedClient memcachedClient = null;  
32.         try {  
33.             memcachedClient = builder.build();  
34.             try {  
35.                 // 设置/获取  
36.                 memcachedClient.set("zlex", 36000, "set/get");  
37.                 assertEquals("set/get", memcachedClient.get("zlex"));  
38.   
39.                 // 替换  
40.                 memcachedClient.replace("zlex", 36000, "replace");  
41.                 assertEquals("replace", memcachedClient.get("zlex"));  
42.   
43.                 // 移除  
44.                 memcachedClient.delete("zlex");  
45.                 assertNull(memcachedClient.get("zlex"));  
46.             } catch (TimeoutException e) {  
47.                 // TODO Auto-generated catch block  
48.                 e.printStackTrace();  
49.             } catch (InterruptedException e) {  
50.                 // TODO Auto-generated catch block  
51.                 e.printStackTrace();  
52.             } catch (MemcachedException e) {  
53.                 // TODO Auto-generated catch block  
54.                 e.printStackTrace();  
55.             }  
56.   
57.         } catch (IOException e) {  
58.             // TODO Auto-generated catch block  
59.             e.printStackTrace();  
60.         } finally {  
61.             if (memcachedClient != null) {  
62.                 try {  
63.                     memcachedClient.shutdown();  
64.                 } catch (IOException e) {  
65.                     // TODO Auto-generated catch block  
66.                     e.printStackTrace();  
67.                 }  
68.             }  
69.         }  
70.     }  
71. }  

四、XMemcached与Spring集成 
XMemcached与Spring集成可以参考http://code.google.com/p/xmemcached/wiki/Spring_Integration，这里只说最常用的方法。 
memcached.properties做基本配置： 

Properties代码  

1. #连接池大小即客户端个数  
2. memcached.connectionPoolSize=50  
3. memcached.failureMode=true  
4. #server1  
5. memcached.server1.host=10.11.155.26  
6. memcached.server1.port=11211  
7. memcached.server1.weight=4  
8. #server2  
9. memcached.server2.host=10.11.155.41  
10. memcached.server2.port=11211  
11. memcached.server2.weight=3                
12. #server3  
13. memcached.server3.host=10.10.76.31  
14. memcached.server3.port=11211  
15. memcached.server3.weight=2                    
16. #server4  
17. memcached.server4.host=10.10.76.35  
18. memcached.server4.port=11211  
19. memcached.server4.weight=1         
20.        

XML配置文件： 

Xml代码  

1. <?xml version="1.0" encoding="UTF-8"?>  
2. <beans  
3.     xmlns="http://www.springframework.org/schema/beans"  
4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
5.     xmlns:context="http://www.springframework.org/schema/context"  
6.     xmlns:p="http://www.springframework.org/schema/p"  
7.     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd  
8.         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">  
9.     <!-- http://code.google.com/p/xmemcached/wiki/Spring_Integration -->  
10.     <context:property-placeholder location="memcached.properties" />  
11.     <bean  
12.         id="memcachedClientBuilder"  
13.         class="net.rubyeye.xmemcached.XMemcachedClientBuilder"  
14.         p:connectionPoolSize="${memcached.connectionPoolSize}"  
15.         p:failureMode="${memcached.failureMode}">  
16.         <!-- XMemcachedClientBuilder have two arguments.First is server list,and   
17.             second is weights array. -->  
18.         <constructor-arg>  
19.             <list>  
20.                 <bean class="java.net.InetSocketAddress">  
21.                     <constructor-arg>  
22.                         <value>${memcached.server1.host}</value>  
23.                     </constructor-arg>  
24.                     <constructor-arg>  
25.                         <value>${memcached.server1.port}</value>  
26.                     </constructor-arg>  
27.                 </bean>  
28.                 <bean class="java.net.InetSocketAddress">  
29.                     <constructor-arg>  
30.                         <value>${memcached.server2.host}</value>  
31.                     </constructor-arg>  
32.                     <constructor-arg>  
33.                         <value>${memcached.server2.port}</value>  
34.                     </constructor-arg>  
35.                 </bean>  
36.                 <bean class="java.net.InetSocketAddress">  
37.                     <constructor-arg>  
38.                         <value>${memcached.server3.host}</value>  
39.                     </constructor-arg>  
40.                     <constructor-arg>  
41.                         <value>${memcached.server3.port}</value>  
42.                     </constructor-arg>  
43.                 </bean>  
44.                 <bean class="java.net.InetSocketAddress">  
45.                     <constructor-arg>  
46.                         <value>${memcached.server4.host}</value>  
47.                     </constructor-arg>  
48.                     <constructor-arg>  
49.                         <value>${memcached.server4.port}</value>  
50.                     </constructor-arg>  
51.                 </bean>  
52.             </list>  
53.         </constructor-arg>  
54.         <constructor-arg>  
55.             <list>  
56.                 <value>${memcached.server1.weight}</value>  
57.                 <value>${memcached.server2.weight}</value>  
58.                 <value>${memcached.server3.weight}</value>  
59.                 <value>${memcached.server4.weight}</value>  
60.             </list>  
61.         </constructor-arg>  
62.         <property name="commandFactory">  
63.             <bean class="net.rubyeye.xmemcached.command.TextCommandFactory" />  
64.         </property>  
65.         <property name="sessionLocator">  
66.             <bean class="net.rubyeye.xmemcached.impl.KetamaMemcachedSessionLocator" />  
67.         </property>  
68.         <property name="transcoder">  
69.             <bean class="net.rubyeye.xmemcached.transcoders.SerializingTranscoder" />  
70.         </property>  
71.     </bean>  
72.     <!-- Use factory bean to build memcached client -->  
73.     <bean  
74.         id="memcachedClient"  
75.         factory-bean="memcachedClientBuilder"  
76.         factory-method="build"  
77.         destroy-method="shutdown" />  
78. </beans>  

这里的memcachedClientBuilder节点完成MemcachedClientBuilder，然后通过memcachedClient节点配置factory-method，调用MemcachedClientBuilder的build()方法产生MemcachedClient，并配置destroy-method进行关闭。 
不过我还是疑惑，这里的异常由谁来处理？Spring容器吗？ 或者需要另一个代理Bean包装一下？ 

有了Spring容器支持，我们不需要在代码中进行配置，也不需要重复调用build()跟shutdown()方法，这些操作交给Spring来完成。 
代码如下： 

Java代码  

1. import static junit.framework.Assert.*;  
2.   
3. import java.util.concurrent.TimeoutException;  
4.   
5. import net.rubyeye.xmemcached.MemcachedClient;  
6. import net.rubyeye.xmemcached.exception.MemcachedException;  
7.   
8. import org.junit.Before;  
9. import org.junit.Test;  
10. import org.springframework.context.ApplicationContext;  
11. import org.springframework.context.support.ClassPathXmlApplicationContext;  
12.   
13. public class MemcachedSpringTest {  
14.   
15.     private ApplicationContext app;  
16.     private MemcachedClient memcachedClient;  
17.   
18.     @Before  
19.     public void init() {  
20.         app = new ClassPathXmlApplicationContext("applicationContext.xml");  
21.         memcachedClient = (MemcachedClient) app.getBean("memcachedClient");  
22.     }  
23.   
24.     @Test  
25.     public void test() {  
26.         try {  
27.             // 设置/获取  
28.             memcachedClient.set("zlex", 36000, "set/get");  
29.             assertEquals("set/get", memcachedClient.get("zlex"));  
30.   
31.             // 替换  
32.             memcachedClient.replace("zlex", 36000, "replace");  
33.             assertEquals("replace", memcachedClient.get("zlex"));  
34.   
35.             // 移除  
36.             memcachedClient.delete("zlex");  
37.             assertNull(memcachedClient.get("zlex"));  
38.         } catch (TimeoutException e) {  
39.             // TODO Auto-generated catch block  
40.             e.printStackTrace();  
41.         } catch (InterruptedException e) {  
42.             // TODO Auto-generated catch block  
43.             e.printStackTrace();  
44.         } catch (MemcachedException e) {  
45.             // TODO Auto-generated catch block  
46.             e.printStackTrace();  
47.         }  
48.     }  
49. }