概述的介绍web应用系统当中各个层面的缓存策略

1. 缓存技术浅谈 Robbin Fan

3. 基于 Web 应用的系统架构图 数据库 应用服务器 Web 服务器 存储设备 浏览器 Web 应用架构 操作系统的文件系统

7. Windows 的 Disk Cache

8. Linux 的 Disk Cache

12. Query Cache 状态示例 __ Query Cache ______________________________________________ Memory usage 25.77M of 64.00M %Used: 40.26 Block Fragmnt 24.73% Hits 6.98M 3.2/s Inserts 100.87M 46.9/s Insrt:Prune 34.15:1 45.5/s Hit:Insert 0.07:1

15. InnoDB buffer 状态示例 __ InnoDB Buffer Pool ______________________________________ Usage 1000.00 of 1000.00 %Used: 100.00 Read hit 99.99% Pages Free 0 %Total: 0.00 Data 59.69k 93.26 % Drty: 0.02 Misc 4311 6.74 Latched 0 0.00 Reads 60.30G 28.0k/s From file 7.01M 3.3/s 0.01 Ahead Rnd 98684 0.0/s Ahead Sql 9548 0.0/s Writes 86.79M 40.3/s Flushes 14.08M 6.5/s Wait Free 0 0/s

19. Hibernate 对象缓存配置 @Entity @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE) public class Forest { ... } 配置 entity 对象缓存 配置关联集合的缓存 @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER) @JoinColumn(name=&quot;CUST_ID&quot;) @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE) public SortedSet<Ticket> getTickets() { return tickets; } 仅仅添加 Annotation 就可以了，无须编码，即可自动享受对象缓存。 Hibernate 会拦截对象的 CRUD 操作，针对对象读取操作进行缓存，针对对象修改操作自动清理缓存

27. OSCache Servlet 缓存示例 <filter> <filter-name>CacheFilter</filter-name> <filter-class>com.opensymphony.oscache.web.filter.CacheFilter</filter-class> <init-param> <param-name>time</param-name> <param-value>600</param-value> </init-param> <init-param> <param-name>scope</param-name> <param-value>session</param-value> </init-param> </filter> <filter-mapping> <filter-name>CacheFilter</filter-name> <url-pattern>/news/*</url-pattern> </filter-mapping>

29. OSCache 的页面局部缓存 <%@ taglib uri=&quot;http://www.opensymphony.com/oscache&quot; prefix=&quot;cache&quot; %> <cache:cache> ... some jsp content ... </cache:cache> <cache:cache key=&quot;foobar&quot; scope=&quot;session&quot;> ... some jsp content ... </cache:cache> <cache:cache key=&quot;<%= product.getId() %>&quot; time=&quot;1800&quot; refresh=&quot;<%= needRefresh %>&quot;> ... some jsp content ... </cache:cache> <cache:cache key=&quot;<%= product.getId() %>&quot; cron=&quot;0 2 * * *&quot; refresh=&quot;<%= needRefresh %>&quot;> ... some jsp content ... </cache:cache>

34. 未使用 AJAX 缓存代码 1. <script src=&quot;jQuery.js&quot;></script> 2. <script language=&quot;JavaScript&quot;> 3. <!-- 4. function gopage(option,obj){ 5. var page = $(&quot;#page&quot;).html() * 1; 6. obj.disabled = true; 7. if(option == '+'){ 8. page ++ ; 9. var url = &quot;data.php?page=&quot;+page + &quot;&r=&quot;+Math.random(); 10. // 获取 ajax url ，后面的 random 是为了防止浏览器缓存 xml 内容 11. }else{ 12. page --; 13. if(page < 1)page =1; 14. var url = &quot;data.php?page=&quot;+page + &quot;&r=&quot;+Math.random(); 15. 16. } 17. $(&quot;#data&quot;).html(&quot;loading...&quot;);// 设置 loading 状态 18. $(&quot;#page&quot;).html(page); 19. // 下面是 ajax 处理 20. $(&quot;#data&quot;).load(url, 21. {limit: 25}, 22. function() { obj.disabled = false; } 23. ); 24. 25. } 26. //--> 27. </script> 28. <input value=&quot;<&quot; onclick=&quot;gopage('-',this)&quot; type=&quot;button&quot;> 29. <input value=&quot;>&quot; onclick=&quot;gopage('+',this)&quot; type=&quot;button&quot;> 30. page:<span id=&quot;page&quot;>1</span> 31. <div style=&quot;border: 2px solid red; padding: 2px;&quot; id=&quot;data&quot;>data area</div>

35. 使用 AJAX 缓存代码 # <script language=&quot;JavaScript&quot;> # <!-- # var cache_data = new Array();// 定义全局变量用来保存缓存数据 # function gopageCache(option,obj){ # var page = $(&quot;#page2&quot;).html() * 1; # if(option == '+'){ # page ++ ; # var url = &quot;data.php?page=&quot;+page + &quot;&r=&quot;+Math.random(); # }else{ # page --; # if(page < 1)page =1; # var url = &quot;data.php?page=&quot;+page + &quot;&r=&quot;+Math.random(); # # } # /* 下面是缓存增加的部分 */ # if( (cache_data[page] !=null) && (cache_data[page].length > 1) ) { # // 如果缓存存在 , 则直接调用缓存数据 , 不用再去服务器进行数据请求 # alert('cache hit'); # $(&quot;#data2&quot;).html(cache_data[page]); # $(&quot;#page2&quot;).html(page); # return true; # } # $(&quot;#page2&quot;).html(page); # obj.disabled = true; # $(&quot;#data2&quot;).html(&quot;loading(cache enabled)...&quot;); # $(&quot;#data2&quot;).load(url, # {limit: 25}, # function(responseText) { obj.disabled = false; # cache_data[page] = responseText;// 将当前的数据存入到内存 ( 缓存变量 ) 中 } # ); # # } # # //--> # </script> # <input value=&quot;<&quot; onclick=&quot;gopageCache('-',this)&quot; type=&quot;button&quot;> # <input value=&quot;>&quot; onclick=&quot;gopageCache('+',this)&quot; type=&quot;button&quot;> # page:<span id=&quot;page2&quot;>1</span> # <div style=&quot;border: 2px solid red; padding: 2px;&quot; id=&quot;data2&quot;>data area</div>

36. 基于 HTTP 协议的资源缓存 Etag &quot;12523074“ Last-Modified Thu, 29 May 2008 09:43:46 GMT /blog /blog If-Modified-Since Thu, 29 May 2008 09:43:46 GMT If-None-Match &quot;12523074 &quot; 304 Not Modified

37. 基于资源的缓存示例 <filter> <filter-name>CacheFilterStaticContent</filter-name> <filter-class>com.opensymphony.oscache.web.filter.CacheFilter</filter-class> <init-param> <param-name>expires</param-name> <param-value>time</param-value> </init-param> </filter> <filter-mapping> <filter-name>CacheFilterStaticContent</filter-name> <url-pattern>*.jsp</url-pattern> </filter-mapping>

38. 谢 谢！