Cache J2EE

 String myKey = "myKey";
 String myValue;
 int myRefreshPeriod = 1000;
 try {
     // Get from the cache
     myValue = (String) admin.getFromCache(myKey, myRefreshPeriod);
 } catch (NeedsRefreshException nre) {
     try {
         // Get the value (probably from the database)
         myValue = "This is the content retrieved.";
         // Store in the cache
         admin.putInCache(myKey, myValue);
     } catch (Exception ex) {
         // We have the current content if we want fail-over.
         myValue = (String) nre.getCacheContent();
         // It is essential that cancelUpdate is called if the
         // cached content is not rebuilt
         admin.cancelUpdate(myKey);
     }
 }

 String myKey = "myKey";
 String myValue;
 int myRefreshPeriod = 1000;
 try {
     // Get from the cache
     myValue = (String) admin.getFromCache(myKey, myRefreshPeriod);
 } catch (NeedsRefreshException nre) {
     try {
         // Get the value (probably from the database)
         myValue = "This is the content retrieved.";
         // Store in the cache
         admin.putInCache(myKey, myValue);
         updated = true;
     } finally {
         if (!updated) {
             // It is essential that cancelUpdate is called if the
             // cached content could not be rebuilt
             admin.cancelUpdate(myKey);
         }
     }
 }

<ehcache>

    <diskStore path="java.io.tmpdir"/>

    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="true"
        diskPersistent="false"
        diskExpiryThreadIntervalSeconds="120"
        />

    <cache name="sampleCache1"
        maxElementsInMemory="10000"
        eternal="false"
        overflowToDisk="false"
        timeToIdleSeconds="300"
        timeToLiveSeconds="600"
        />

</ehcache>

 public class TestServlet extends HttpServlet {
 
 private static Logger logger = Logger.getLogger(TestServlet.class.getName());
 private CacheManager manager = null;
 private Cache cache = null;
 
 public void init() throws ServletException {
        // Configuration de log4J.
        PropertyConfigurator.configure( getServletContext().getRealPath ("WEB-INF/log4j.properties"));
        // Creating the cache manager from configuration file
        try {
            manager = CacheManager.create(getServletContext().getRealPath ("WEB-INF/ehCache.xml"));
            cache = manager.getCache("sampleCache1");
        } catch (Exception e) {
            logger.error("Unable to load EHCACHE configuration file");
        }
 }
 
 public void destroy() {
 }
 
 protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Creation du writer de sortie.
        PrintWriter out = response.getWriter();
        // Creation d'un objet
        Object myObject = new Object();
        // Mise en cache de cet element
        Element element = new Element("testID", myObject);
        cache.put(element);
        out.println ("Objet mis en cache`<br/>`");   
        // Lecture du cache pour extraire l'objet
        try {
            element = cache.get("testID");
        } catch (Exception e) {}
        Object mySecondObject = element.getValue();
 }
 }

 public class PersonCache extends GenericEntity {
 
         ObjectCache cache;
         
         public PersonEntity(CacheFactory cacheFactory) {
                 cache = cacheFactory.createCache("Person");
                 // * Other initialization here
         }
         
         public Person get(long key) {
                 Long cacheKey = new Long(key);
                 Person person = (Person)cache.get(cachekey);
                 if (person == null) {
                         // * Get the object from the database                   
                         if (person != null) {
                                 // Put it in the cache
                                 cache.put(cacheKey, person);
                         }
                 }
                 return person;
         }
         
         public void insert(Person person) {
                 // * Do database insert
                 // Add new object to cache
                 Long cacheKey = new Long(person.getKey());
                 cache.put(cacheKey, person);
         }
         
         public void update(Person person) {
                 // * Do database update
                 // Remove object from cache
                 // (This causes all caches in the group to be notified)
                 Long cacheKey = new Long(person.getKey());
                 cache.clear(cacheKey);
                 // Re-add the object to the cache
                 cache.put(cacheKey, person);
         }
         
         public void delete(long key) {
                 // * Do database delete
                 // Remove object from cache
                 // (This causes all caches in the group to be notified)
                 Long cacheKey = new Long(key);
                 cache.clear(cacheKey);          
         }
         
 }

 ArrayList list = new ArrayList();
 list.add("first");
 cache.putObject("/list/test", list); // Put the list under the aop cache
 list.add("second"); // Won't work since AOP intercepts the dynamic proxy not the original POJO.
 ArrayList myList = (List)cache.getObject("/list/test"); // we are getting a dynamic proxy instead
 myList.add("second"); // it works now
 myList.add("third");
 myList.remove("third");