刘文涛

1 JSP Caching
2 Request Caching
3 General - Purpose Cache

1 缓冲到磁盘
2 可编程的缓冲刷新
3 异常控制，

1 public   interface  Cache  { 
2  Object get(Object key)  throws  CacheException; 
3   void  put(Object key, Object value)  throws  CacheException; 
4   void  remove(Object key)  throws  CacheException; 
5   void  clear()  throws  CacheException; 
6   void  destroy()  throws  CacheException;
7 }  

 1 public   class  OSCache  implements  Cache  { 
 2      private  GeneralCacheAdministrator cache  =   null ; 
 3          public  OSCache(Properties prop)  { 
 4         cache  =   new  GeneralCacheAdministrator(prop); 
 5     }  
 6
 7      public   void  setCacheCapacity( int  cacheCapacity)  { 
 8         cache.setCacheCapacity(cacheCapacity); 
 9     }  
10
11      public  Object get(Object key)  throws  CacheException  { 
12          try   { 
13              return  cache.getFromCache(String.valueOf(key)); 
14         }   catch  (NeedsRefreshException e)  { 
15             cache.cancelUpdate(String.valueOf(key)); 
16              return   null ; 
17         }  
18     }  
19
20      public   void  put(Object key, Object value)  throws  CacheException  { 
21         cache.putInCache(String.valueOf(key), value); 
22     }  
23
24      public   void  remove(Object key)  throws  CacheException  { 
25         cache.flushEntry(String.valueOf(key)); 
26     }  
27
28      public   void  clear()  throws  CacheException  { 
29         cache.flushAll(); 
30     }  
31
32      public   void  destroy()  throws  CacheException  { 
33         cache.destroy(); 
34     }  
35 }  

 1 public   class  CacheManager  { 
 2      // $SUP-USP$ 
 3      private   static  Map cacheMap  =   new  HashMap(); 
 4      private   static  Config config  =  ConfigManager.getConfig(); 
 5
 6      private  CacheManager()  { 
 7     }  
 8
 9      public   static  Cache getCache(Class clazz)  { 
10          return  getCache(clazz.getName()); 
11     }  
12
13      public   static  Cache getCache(String cacheId)  { 
14         Cache cache  =   null ; 
15         cache  =  (Cache) cacheMap.get(cacheId); 
16          if  (cache  ==   null )  { 
17             cache  =   new  OSCache(config.getProperties()); 
18             cacheMap.put(cacheId, cache); 
19         }  
20          return  cache; 
21     }  
22 }  

1 java对象，
2 页面
3 http请求
4 二进制内容：例如PDF文件

1 JavaGroups[http: // www.jgroups.org]
2 JMS

二、下面给出 OScache 官方文档对 JavaGroups 使用的说明：     

JavaGroups Configuration
Just make sure you have jgroups-all.jar file in your classpath (for a webapp put it in WEB-INF/lib), and add the JavaGroups broadcasting listener to your oscache.properties file like this:

cache.event.listeners=com.opensymphony.oscache.plugins.clustersupport.JavaGroupsBroadcastingListener

In most cases, that's it! OSCache will now broadcast any cache flush events across the LAN. The jgroups-all.jar library is not included with the binary distribution due to its size, however you can obtain it either by downloading the full OSCache distribution, or by visiting the JavaGroups website.

If you want to run more than one OSCache cluster on the same LAN, you will need to use different multicast IP addresses. This allows the caches to exist in separate multicast groups and therefore not interfere with each other. The IP to use can be specified in your oscache.properties file by the cache.cluster.multicast.ip property. The default value is 231.12.21.132, however you can use any class D IP address. Class D address fall in the range 224.0.0.0 through 239.255.255.255.

If you need more control over the multicast configuration (eg setting network timeout or time-to-live values), you can use the cache.cluster.properties configuration property. Use this instead of the cache.cluster.multicast.ip property. The default value is:

UDP(mcast_addr=231.12.21.132;mcast_port=45566;ip_ttl=32;\
mcast_send_buf_size=150000;mcast_recv_buf_size=80000):\
PING(timeout=2000;num_initial_members=3):\
MERGE2(min_interval=5000;max_interval=10000):\
FD_SOCK:VERIFY_SUSPECT(timeout=1500):\
pbcast.NAKACK(gc_lag=50;retransmit_timeout=300,600,1200,2400,4800;max_xmit_size=8192):\
UNICAST(timeout=300,600,1200,2400):\
pbcast.STABLE(desired_avg_gossip=20000):\
FRAG(frag_size=8096;down_thread=false;up_thread=false):\
pbcast.GMS(join_timeout=5000;join_retry_timeout=2000;shun=false;print_local_addr=true)

See the JavaGroups site for more information. In particular, look at the documentation of Channels in the User's Guide.

# CACHE IN MEMORY
#
# If you want to disable memory caching, just uncomment this line.
#
# 不使用内存
cache.memory=false

# CACHE KEY
#
# This is the key that will be used to store the cache in the application
# and session scope.
#
# If you want to set the cache key to anything other than the default
# uncomment this line and change the cache.key
#
# cache.key=__oscache_cache

# USE HOST DOMAIN NAME IN KEY
#
# Servers for multiple host domains may wish to add host name info to
# the generation of the key. If this is true, then uncomment the
# following line.
#
# cache.use.host.domain.in.key=true

# CACHE LISTENERS
#
# These hook OSCache events and perform various actions such as logging
# cache hits and misses, or broadcasting to other cache instances across a cluster.
# See the documentation for further information.
#
# cache.event.listeners=com.opensymphony.oscache.plugins.clustersupport.JMSBroadcastingListener, \
# com.opensymphony.oscache.extra.CacheEntryEventListenerImpl, \
# com.opensymphony.oscache.extra.CacheMapAccessEventListenerImpl, \
# com.opensymphony.oscache.extra.ScopeEventListenerImpl

# 使用 JavaGroups 来实现监听广播式缓存
cache.event.listeners=com.opensymphony.oscache.plugins.clustersupport.JavaGroupsBroadcastingListener

# CACHE PERSISTENCE CLASS
#
# Specify the class to use for persistence. If you use the supplied DiskPersistenceListener,
# don't forget to supply the cache.path property to specify the location of the cache
# directory.
#
# If a persistence class is not specified, OSCache will use memory caching only.
#
# 启动硬盘持久化 Cache
cache.persistence.class=com.opensymphony.oscache.plugins.diskpersistence.DiskPersistenceListener

# CACHE OVERFLOW PERSISTENCE
# Use persistent cache in overflow or not. The default value is false, which means
# the persistent cache will be used at all times for every entry. true is the recommended setting.
#
# cache.persistence.overflow.only=true

# CACHE DIRECTORY
#
# This is the directory on disk where caches will be stored by the DiskPersistenceListener.
# it will be created if it doesn't already exist. Remember that OSCache must have
# write permission to this directory.
#
# Note: for Windows machines, this needs \ to be escaped
# ie Windows:
# cache.path=c:\\myapp\\cache
# or *ix:

# 在Linux下的Cache存放路径
cache.path=/data/jsp/boss.21cn.com/bossimpls/cache/bossuud
#
# cache.path=c:\\app\\cache

# CACHE ALGORITHM
#
# Default cache algorithm to use. Note that in order to use an algorithm
# the cache size must also be specified. If the cache size is not specified,
# the cache algorithm will be Unlimited cache.
#

#使用LRU运算算法，把最少使用的Cache剔除出去
cache.algorithm=com.opensymphony.oscache.base.algorithm.LRUCache
# cache.algorithm=com.opensymphony.oscache.base.algorithm.FIFOCache
# cache.algorithm=com.opensymphony.oscache.base.algorithm.UnlimitedCache

# THREAD BLOCKING BEHAVIOR
#
# When a request is made for a stale cache entry, it is possible that another thread is already
# in the process of rebuilding that entry. This setting specifies how OSCache handles the
# subsequent 'non-building' threads. The default behaviour (cache.blocking=false) is to serve
# the old content to subsequent threads until the cache entry has been updated. This provides
# the best performance (at the cost of serving slightly stale data). When blocking is enabled,
# threads will instead block until the new cache entry is ready to be served. Once the new entry
# is put in the cache the blocked threads will be restarted and given the new entry.
# Note that even if blocking is disabled, when there is no stale data available to be served
# threads will block until the data is added to the cache by the thread that is responsible
# for building the data.
#
# cache.blocking=false

# CACHE SIZE
#
# Default cache size in number of items. If a size is specified but not
# an algorithm, the cache algorithm used will be LRUCache.
#

#这个值设得够大了，就是Cache的容量项目个数
cache.capacity=100000000

# CACHE UNLIMITED DISK
# Use unlimited disk cache or not. The default value is false, which means
# the disk cache will be limited in size to the value specified by cache.capacity.
#

#不使用无限硬盘空间
cache.unlimited.disk=false

# JMS CLUSTER PROPERTIES
#
# Configuration properties for JMS clustering. See the clustering documentation
# for more information on these settings.
#
#cache.cluster.jms.topic.factory=java:comp/env/jms/TopicConnectionFactory
#cache.cluster.jms.topic.name=java:comp/env/jms/OSCacheTopic
#cache.cluster.jms.node.name=node1

# JAVAGROUPS CLUSTER PROPERTIES
#
# Configuration properites for the JavaGroups clustering. Only one of these
# should be specified. Default values (as shown below) will be used if niether
# property is set. See the clustering documentation and the JavaGroups project
# (www.javagroups.com) for more information on these settings.
#
cache.cluster.properties=UDP(mcast_addr=231.12.21.132;mcast_port=45566;ip_ttl=32;\
mcast_send_buf_size=150000;mcast_recv_buf_size=80000):\
PING(timeout=2000;num_initial_members=3):\
MERGE2(min_interval=5000;max_interval=10000):\
FD_SOCK:VERIFY_SUSPECT(timeout=1500):\
pbcast.NAKACK(gc_lag=50;retransmit_timeout=300,600,1200,2400,4800;max_xmit_size=8192):\
UNICAST(timeout=300,600,1200,2400):\
pbcast.STABLE(desired_avg_gossip=20000):\
FRAG(frag_size=8096;down_thread=false;up_thread=false):\
pbcast.GMS(join_timeout=5000;join_retry_timeout=2000;shun=false;print_local_addr=true)
cache.cluster.multicast.ip=231.12.21.132

网名：润名
E-mail: winsonhrh@gmail.com
现从事于 21cn 公司，从事 J2EE 架构设计，有四年 J2EE工作经验。善长于对 Open Source Framework的技术整合开发和各种应用服务器的调优。

1 、被处理的内容短时间不变，所以短时间内可以作为静态内容进行处理
2 、在一个不太长的时间内，被处理的内容可能或者必定产生变化，所以必须将他们作为动态内容进行处理
3 、在合理的时间区段内可以忽略被处理内容变化后带来的影响
4 、对这些内容的处理动作比较消耗系统性能，影响系统响应时间

1 降低系统性能消耗
2 提高系统稳定性
3 提高并发处理能力

1 OrionServer ( 1.4 .0或者以上版本)
2 Macromedia JRun ( 3 .0或者以上版本)
3 BEA Weblogic ( 7 .x或者以上版本)
4 IBM Websphere ( 5 .0版本)
5 Silverstream ( 3.7 .4版本)
6 Caucho Resin ( 1.2 .3或者以上版本)
7 Tomcat ( 4 .0或者以上版本)
8 其他支持servlet2. 3 、jsp1.2的web服务器

1 使用内存作为缓存区将可以提供更好的性能 
2 使用硬盘作为缓存区可以在服务器重起后迅速恢复缓存内容 
3 同时使用内存和硬盘作为缓存区则可以减少对内存的占用 

1 1 . 缓存时间超过了cache标签设置的time或者duration属性规定的超时时间 
2 2 . cron属性规定的时间比缓存信息的开始时间更晚 
3 3 . 标签中缓存的内容在缓存后又被重新刷新过 
4 4 . 其他缓存超期设定

你可以在同一个页面中使用很多cache标签而不指定他的key属性，这种情况下系统使用该页面的URI和后面的请求字符串，另外再自动给这些key增加一个索引值来区分这些缓存内容。但是不推荐采用这样的方式。

1 silent
2 cron
3 groups
4 language
5 refreshpolicyclass
6 refreshpolicyparam

1 < cache:cache >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < cache:cache key = " foobar "  scope = " session " >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < cache:cache key = " <%= product.getId() %> "  time = " 1800 "  refresh = " <%= needRefresh %> " >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < cache:cache time = " -1 " >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < cache:cache  duration = ' PT5M ' >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < cache:cache  mode = ' silent ' >
2      <%
3      // 自己的JSP代码内容
4      %>
5 </ cache:cache >  

1 < filter >
2      < filter - name > CacheFilter </ filter - name >
3      < filter - class > com.opensymphony.oscache.web.filter.CacheFilter </ filter - class >
4 </ filter >

1 < filter - mapping >
2      < filter - name > CacheFilter </ filter - name >
3      <!- 对 / testContent.jsp页面内容进行缓存 -->
4      < url - pattern >/ testContent.jsp </ url - pattern >
5 </ filter - mapping >

1 < filter - mapping >
2      < filter - name > CacheFilter </ filter - name >
3      <!- 对所有jsp页面内容进行缓存 -->
4          < url - pattern >* .jsp </ url - pattern >
5 </ filter - mapping >