Java缓存组件 EhCache 入门教程

01

<

filter

>

02

<

filter-name

>indexCacheFilterfilter-name>

03

<

filter-class

>

04

net.sf.ehcache.constructs.web.filter.SimplePageCachingFilter

05

<

filter-class

>

06

<

filter

>

07

<

filter-mapping

>

08

<

filter-name

>indexCacheFilterfilter-name>

09

<

url-pattern

>*index.actionurl-pattern>

10

<

filter-mapping

>

01

<

filter

>

02

<

filter-name

>indexCacheFilterfilter-name>

03

<

filter-class

>

04

net.sf.ehcache.constructs.web.filter.SimplePageFragmentCachingFilter

05

<

filter-class

>

06

filter>

07

<

filter-mapping

>

08

<

filter-name

>indexCacheFilterfilter-name>

09

<

url-pattern

>*/index_right.jsp<

url-pattern

>

10

<

filter-mapping

>

01

public

class

MethodCacheInterceptor

implements

MethodInterceptor,
InitializingBean

02

{

03

private

static

final

Log
logger = LogFactory.getLog(MethodCacheInterceptor.

class

);

04

private

Cache
cache;

05

public

void

setCache(Cache
cache) {

06

this

.cache
= cache;

07

}

08

public

MethodCacheInterceptor()
{

09

super

();

10

}

11

/**

12

*
拦截Service/DAO 的方法，并查找该结果是否存在，如果存在就返回cache 中的值，

13

*
否则，返回数据库查询结果，并将查询结果放入cache

14

*/

15

public

Object
invoke(MethodInvocation invocation)

throws

Throwable
{

16

String
targetName = invocation.getThis().getClass().getName();

17

String
methodName = invocation.getMethod().getName();

18

Object[]
arguments = invocation.getArguments();

19

Object
result;

20

logger.debug(

"Find
object from cache is "

+
cache.getName());

21

String
cacheKey = getCacheKey(targetName, methodName, arguments);

22

Element
element = cache.get(cacheKey);

23

Page

13

of

26

24

if

(element
==

null

)
{

25

logger.debug(

"Hold
up method , Get method result and create cache........!"

);

26

result
= invocation.proceed();

27

element
=

new

Element(cacheKey,
(Serializable) result);

28

cache.put(element);

29

}

30

return

element.getValue();

31

}

32

/**

33

*
获得cache key 的方法，cache key 是Cache 中一个Element 的唯一标识

34

*
cache key 包括包名+类名+方法名，如com.co.cache.service.UserServiceImpl.getAllUser

35

*/

36

private

String
getCacheKey(String targetName, String methodName, Object[] arguments) {

37

StringBuffer
sb =

new

StringBuffer();

38

sb.append(targetName).append(

"."

).append(methodName);

39

if

((arguments
!=

null

)
&& (arguments.length !=

0

))
{

40

for

(

int

i
=

0

;
i < arguments.length; i++) {

41

sb.append(

"."

).append(arguments[i]);

42

}

43

}

44

return

sb.toString();

45

}

46

/**

47

*
implement InitializingBean，检查cache 是否为空

48

*/

49

public

void

afterPropertiesSet()

throws

Exception
{

50

Assert.notNull(cache,

"Need
a cache. Please use setCache(Cache) create it."

);

51

}

52

}

01

public

class

MethodCacheAfterAdvice

implements

AfterReturningAdvice,
InitializingBean

02

{

03

private

static

final

Log
logger = LogFactory.getLog(MethodCacheAfterAdvice.

class

);

04

private

Cache
cache;

05

Page

15

of

26

06

public

void

setCache(Cache
cache) {

07

this

.cache
= cache;

08

}

09

public

MethodCacheAfterAdvice()
{

10

super

();

11

}

12

public

void

afterReturning(Object
arg0, Method arg1, Object[] arg2, Object arg3)

throws

13

Throwable
{

14

String
className = arg3.getClass().getName();

15

List
list = cache.getKeys();

16

for

(

int

i
=

0

;i<list.size();i++){

17

String
cacheKey = String.valueOf(list.get(i));

18

if

(cacheKey.startsWith(className)){

19

cache.remove(cacheKey);

20

logger.debug(

"remove
cache "

+
cacheKey);

21

}

22

}

23

}

24

public

void

afterPropertiesSet()

throws

Exception
{

25

Assert.notNull(cache,

"Need
a cache. Please use setCache(Cache) create it."

);

26

}

27

}

01

<

ehcache

>

02

<

diskStore

path

=

"c:\\myapp\\cache"

/>

03

<

defaultCache

04

maxElementsInMemory

=

"1000"

05

eternal

=

"false"

06

timeToIdleSeconds

=

"120"

07

timeToLiveSeconds

=

"120"

08

overflowToDisk

=

"true"

09

/>

10

<

cache

name

=

"DEFAULT_CACHE"

11

maxElementsInMemory

=

"10000"

12

eternal

=

"false"

13

timeToIdleSeconds

=

"300000"

14

timeToLiveSeconds

=

"600000"

15

overflowToDisk

=

"true"

16

/>

17

</

ehcache

>