用观察者模式解决点击一次文章 update一次数据库的问题
接上文http://xuliangyong.iteye.com/blog/171240
对于第二种方法现用观察着模式来解决
思路是这样：当点击a文章(id=1234)够10次后 ,通知文章管理器更新点击次数
update article set hit_count = hit_count+10 where id = 1234
这样就减少了访问数据库的次数
代码如下：
- publicclassHitCachedextendsObservable{
- privatestaticfinalintDEFAULT_MAX_HITS=10;
- privateMap<Long,Integer>hits=Collections.synchronizedMap(newHashMap<Long,Integer>());
- privateintmaxHits=DEFAULT_MAX_HITS;
- publicHitCached(){}
- publicHitCached(intmaxHits){
- this.maxHits=maxHits;
- }
- publicvoidput(Longkey,Integervalue){
- hits.put(key,value);
- }
- publicvoidaddHit(Longkey,IntegerhitIncreased){
- if(!hits.containsKey(key))
- hits.put(key,0);
- Integervalue=hits.get(key);
- if(value+hitIncreased>=maxHits){
- setChanged();
- notifyObservers(KeyValuePair.create(key,value+hitIncreased));
- hits.remove(key);
- }else{
- hits.put(key,value+hitIncreased);
- }
- }
- publicIntegerget(Longkey){
- returnhits.get(key);
- }
- publicvoidclear(){
- hits.clear();
- }
- }
- publicclassArticleManagerImplextendsHibernateGenericDao<Article,Long>implementsArticleManag
