Memcached学习笔记 — 第四部分:Memcached Java 客户端-gwhalin(1)-介绍及使用

介绍

Memcached java client是官方推荐的最早的memcached java客户端。最新版本：java_memcached-release_2.6.1。

官方下载地址：https://github.com/gwhalin/Memcached-Java-Client

采用阻塞式SOCKET通讯，据说目前版本进行了很多优化，性能有所提高（只看过1.5的源代码，还没来及看最新的）
提供key方式的连接池，默认连接池key为default。（老版本了）。2.6.1版本支持apache-commoms-pool作为连接池。
支持权重配置。
后期的版本提增加了cas支持和getMutl功能

官方示例代码

Java代码

import com.danga.MemCached.MemCachedClient;
import com.danga.MemCached.SockIOPool;
import com.schooner.MemCached.MemcachedItem;
public class MemcachedForJavaExample {
// create a static client as most installs only need
// a single instance
protected static MemCachedClient mcc = new MemCachedClient();
// set up connection pool once at class load
static {
// server list and weights
String[] servers = { "localhost:11211", "localhost:11212", "localhost:11213" };
Integer[] weights = { 3, 3, 2 };
// grab an instance of our connection pool
SockIOPool pool = SockIOPool.getInstance();
// set the servers and the weights
pool.setServers(servers);
pool.setWeights(weights);
pool.setHashingAlg(SockIOPool.CONSISTENT_HASH);
// set some basic pool settings
// 5 initial, 5 min, and 250 max conns
// and set the max idle time for a conn
// to 6 hours
pool.setInitConn(5);
pool.setMinConn(5);
pool.setMaxConn(250);
pool.setMaxIdle(1000 * 60 * 60 * 6);
// set the sleep for the maint thread
// it will wake up every x seconds and
// maintain the pool size
pool.setMaintSleep(30);
// set some TCP settings
// disable nagle
// set the read timeout to 3 secs
// and don't set a connect timeout
pool.setNagle(false);
pool.setSocketTO(3000);
pool.setSocketConnectTO(0);
// initialize the connection pool
pool.initialize();
}
public static void main(String[] args) {
System.out.println("SET: " + mcc.set("key1", "value1"));
System.out.println("SET: " + mcc.set("key2", "value2"));
System.out.println("SET: " + mcc.set("key3", "value3"));
System.out.println("GET: " + mcc.get("key1"));
MemcachedItem item = mcc.gets("key1");
System.out.println("GETS: value=" + item.getValue() + ",CasUnique:"+item.getCasUnique());
System.out.println("SET: " + mcc.set("key1", "value1_1"));
System.out.println("CAS: " + mcc.cas("key1", "value1_2", item.getCasUnique())); //必须FALSE
System.out.println("getMulti:" + mcc.getMulti(new String[]{"key1","key2","key3"}));
}
}

import com.danga.MemCached.MemCachedClient;
import com.danga.MemCached.SockIOPool;
import com.schooner.MemCached.MemcachedItem;public class MemcachedForJavaExample {// create a static client as most installs only need// a single instanceprotected static MemCachedClient mcc = new MemCachedClient();// set up connection pool once at class loadstatic {// server list and weightsString[] servers = { "localhost:11211", "localhost:11212", "localhost:11213" };Integer[] weights = { 3, 3, 2 };// grab an instance of our connection poolSockIOPool pool = SockIOPool.getInstance();// set the servers and the weightspool.setServers(servers);pool.setWeights(weights);pool.setHashingAlg(SockIOPool.CONSISTENT_HASH);// set some basic pool settings// 5 initial, 5 min, and 250 max conns// and set the max idle time for a conn// to 6 hourspool.setInitConn(5);pool.setMinConn(5);pool.setMaxConn(250);pool.setMaxIdle(1000 * 60 * 60 * 6);// set the sleep for the maint thread// it will wake up every x seconds and// maintain the pool sizepool.setMaintSleep(30);// set some TCP settings// disable nagle// set the read timeout to 3 secs// and don't set a connect timeoutpool.setNagle(false);pool.setSocketTO(3000);pool.setSocketConnectTO(0);// initialize the connection poolpool.initialize();}public static void main(String[] args) {System.out.println("SET: " + mcc.set("key1", "value1"));System.out.println("SET: " + mcc.set("key2", "value2"));System.out.println("SET: " + mcc.set("key3", "value3"));System.out.println("GET: " + mcc.get("key1"));MemcachedItem item = mcc.gets("key1");System.out.println("GETS: value=" + item.getValue() + ",CasUnique:"+item.getCasUnique());System.out.println("SET: " + mcc.set("key1", "value1_1"));System.out.println("CAS: " + mcc.cas("key1", "value1_2", item.getCasUnique())); //必须FALSESystem.out.println("getMulti:" + mcc.getMulti(new String[]{"key1","key2","key3"}));}}

我的代码

这个标题不好取，因为是我自己的想法，还需要大家多提意见，一起讨论。想叫“建议代码”或者“推荐代码”，觉得不合适，还是先叫“我的代码”吧，呵呵。

我的思路

1. 在原始客户端上层，根据业务需求封装MemcachedService(或叫MemcachedClient)，负责缓存功能的包装。如：你的业务只需要add,set,get,gets,cas,delete业务，那就只封装这几个功能。这样做的好处是，屏蔽了各种客户端的API差异，让你的业务系统与客户端实现解耦合，如果你以后需要换客户端实现，对你的业务系统不会照成影响。
2. 一般不要直接采用new的方式在你的代码中显示使用memcached客户端实现，应该采用单例的方式使用memcached客户端实现，或者使用Spring的singleton方式配置。Memcached客户端实现是线程安全的。
3. memcached客户端一般都需要大量的配置，考虑扩展和配置修改，应该把参数设置设计为可配置的，可以写到propertis配置文件中或是使用Spring进行配置。

我的实现

业务层封装接口

Java代码

/**
* Memcached 常用功能接口定义,用于业务层直接使用，屏蔽各种客户端实现的API差异，实现解耦客户端与业务系统的目的
* 无过期时间和flags支持，无append,prepend,replace,incr,decr等操作
*
* @author zhangpu
*
*/
public interface MemcachedClientService {
String get(String key);
CacheItem gets(String key);
boolean add(String key, String value);
boolean set(String key, String value);
boolean cas(String key, String value, long unique);
boolean delete(String key)
boolean flushAll();
}

/*** Memcached 常用功能接口定义,用于业务层直接使用，屏蔽各种客户端实现的API差异，实现解耦客户端与业务系统的目的* 无过期时间和flags支持，无append,prepend,replace,incr,decr等操作* * @author zhangpu* */
public interface MemcachedClientService {String get(String key);CacheItem gets(String key);boolean add(String key, String value);boolean set(String key, String value);boolean cas(String key, String value, long unique);boolean delete(String key)boolean flushAll();}

Java代码

public class CacheItem {
private String key;
private String value;
private long unique;
public CacheItem() {
super();
}
public CacheItem(String key, String value, long unique) {
super();
this.key = key;
this.value = value;
this.unique = unique;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
public long getUnique() {
return unique;
}
public void setUnique(long unique) {
this.unique = unique;
}
}

public class CacheItem {private String key;private String value;private long unique;public CacheItem() {super();}public CacheItem(String key, String value, long unique) {super();this.key = key;this.value = value;this.unique = unique;}public String getKey() {return key;}public void setKey(String key) {this.key = key;}public String getValue() {return value;}public void setValue(String value) {this.value = value;}public long getUnique() {return unique;}public void setUnique(long unique) {this.unique = unique;}}

客户端缓存服务实现

Java代码

/**
* Memcached for java客户端缓存服务实现
* @author zhangpu
*
*/
public class MemcachedClientJava implements MemcachedClientService {
MemCachedClient mmc = MemcachedClientFactory.getInstance();
public boolean add(String key, String value) {
return mmc.add(key, value);
}
public boolean cas(String key, String value, long unique) {
return mmc.cas(key, value, unique);
}
public String get(String key) {
return (String) mmc.get(key);
}
public CacheItem gets(String key) {
MemcachedItem item = mmc.gets(key);
return new CacheItem(key, (String) item.getValue(), item.getCasUnique());
}
public boolean set(String key, String value) {
return mmc.set(key, value);
}
public boolean delete(String key) {
return mmc.delete(key);
}
public boolean flushAll() {
return mmc.flushAll();
}
}

/*** Memcached for java客户端缓存服务实现* @author zhangpu**/
public class MemcachedClientJava implements MemcachedClientService {MemCachedClient mmc = MemcachedClientFactory.getInstance();public boolean add(String key, String value) {return mmc.add(key, value);}public boolean cas(String key, String value, long unique) {return mmc.cas(key, value, unique);}public String get(String key) {return (String) mmc.get(key);}public CacheItem gets(String key) {MemcachedItem item = mmc.gets(key);return new CacheItem(key, (String) item.getValue(), item.getCasUnique());}public boolean set(String key, String value) {return mmc.set(key, value);}public boolean delete(String key) {return mmc.delete(key);}public boolean flushAll() {return mmc.flushAll();}}

获取客户端实例

Java代码

/**
* MemcachedClient 单例(JDK1.5以上)
* @author zhangpu
*
*/
public class MemcachedClientFactory extends ConfigurableConstants{
private static volatile MemCachedClient mmc;
static {
init("memcached-client.properties");
//{ "localhost:11211", "localhost:11212", "localhost:11213" };
String[] servers = getProperty("memcached-servers","").split(",");
Integer[] weights = null;
String weightsCfg = getProperty("memcached-weights","");
if(weightsCfg != null){
String[] wcfg = weightsCfg.split(",");
weights = new Integer[wcfg.length];
for (int i = 0; i < weights.length; i++) {
weights[i] = Integer.valueOf(wcfg[i]);
}
}else{
weights = new Integer[servers.length];
for (int i = 0; i < weights.length; i++) {
weights[i] = 1;
}
}
SockIOPool pool = SockIOPool.getInstance();
pool.setServers(servers);
pool.setWeights(weights);
pool.setHashingAlg(SockIOPool.CONSISTENT_HASH);
pool.setInitConn(getProperty("memcached-initConn",5));
pool.setMinConn(getProperty("memcached-minConn",5));
pool.setMaxConn(getProperty("memcached-maxConn",250));
pool.setMaxIdle(1000 * 60 * 60 * 6);
pool.setMaintSleep(30);
pool.setNagle(false);
pool.setSocketTO(3000);
pool.setSocketConnectTO(0);
pool.initialize();
}
private MemcachedClientFactory() {
}
public static MemCachedClient getInstance() {
if (mmc == null) {
synchronized (MemCachedClient.class) {
if (mmc == null) {
mmc = new MemCachedClient();
}
}
}
return mmc;
}
}

/*** MemcachedClient 单例(JDK1.5以上)* @author zhangpu**/
public class MemcachedClientFactory extends ConfigurableConstants{private static volatile MemCachedClient mmc;static {init("memcached-client.properties");//{ "localhost:11211", "localhost:11212", "localhost:11213" };String[] servers = getProperty("memcached-servers","").split(",");Integer[] weights = null;String weightsCfg = getProperty("memcached-weights","");if(weightsCfg != null){String[] wcfg = weightsCfg.split(",");weights = new Integer[wcfg.length];for (int i = 0; i < weights.length; i++) {weights[i] = Integer.valueOf(wcfg[i]);}}else{weights = new Integer[servers.length];for (int i = 0; i < weights.length; i++) {weights[i] = 1;}}SockIOPool pool = SockIOPool.getInstance();pool.setServers(servers);pool.setWeights(weights);pool.setHashingAlg(SockIOPool.CONSISTENT_HASH);pool.setInitConn(getProperty("memcached-initConn",5));pool.setMinConn(getProperty("memcached-minConn",5));pool.setMaxConn(getProperty("memcached-maxConn",250));pool.setMaxIdle(1000 * 60 * 60 * 6);pool.setMaintSleep(30);pool.setNagle(false);pool.setSocketTO(3000);pool.setSocketConnectTO(0);pool.initialize();}private MemcachedClientFactory() {}public static MemCachedClient getInstance() {if (mmc == null) {synchronized (MemCachedClient.class) {if (mmc == null) {mmc = new MemCachedClient();}}}return mmc;}}

参数配置

Java代码

/**
* 通过 properties 文件配置设置常量基类负责加载和读取 properties 属性文件并提供访问的静态工具方法
*
* @author zhangpu
*
*/
public class ConfigurableConstants {
protected static Log logger = LogFactory.getLog(ConfigurableConstants.class);
protected static Properties p = new Properties();
protected static void init(String propertyFileName) {
InputStream in = null;
try {
in = ConfigurableConstants.class.getClassLoader().getResourceAsStream(propertyFileName);
if (in != null)
p.load(in);
} catch (IOException e) {
logger.error("load " + propertyFileName + " into Constants error!");
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
logger.error("close " + propertyFileName + " error!");
}
}
}
}
protected static String getProperty(String key, String defaultValue) {
return p.getProperty(key, defaultValue);
}
protected static int getProperty(String key, int defaultValue) {
try {
return Integer.parseInt(getProperty(key, ""));
} catch (Exception e) {
return defaultValue;
}
}
}

/*** 通过 properties 文件配置设置常量基类 负责加载和读取 properties 属性文件并提供访问的静态工具方法** @author zhangpu**/public class ConfigurableConstants {protected static Log logger = LogFactory.getLog(ConfigurableConstants.class);protected static Properties p = new Properties();protected static void init(String propertyFileName) {InputStream in = null;try {in = ConfigurableConstants.class.getClassLoader().getResourceAsStream(propertyFileName);if (in != null)p.load(in);} catch (IOException e) {logger.error("load " + propertyFileName + " into Constants error!");} finally {if (in != null) {try {in.close();} catch (IOException e) {logger.error("close " + propertyFileName + " error!");}}}}protected static String getProperty(String key, String defaultValue) {return p.getProperty(key, defaultValue);}protected static int getProperty(String key, int defaultValue) {try {return Integer.parseInt(getProperty(key, ""));} catch (Exception e) {return defaultValue;}}}

配置文件

memcached-client.properties

Properties代码

memcached-client.properties
memcached-servers=localhost:11211,localhost:11212,localhost:11213
memcached-weights=3,3,2
memcached-initConn=5
memcached-minConn=5
memcached-maxConn=250

memcached-client.properties
memcached-servers=localhost:11211,localhost:11212,localhost:11213
memcached-weights=3,3,2
memcached-initConn=5
memcached-minConn=5
memcached-maxConn=250

后续提供性能测试，spring整合，版本差异测试，及其它客户端对比。