学步园

OSCache简单例子

1.  BaseCache.java  基类

package com.yanek.demo.cache.oscache;

import java.util.Date;

import com.opensymphony.oscache.base.NeedsRefreshException;
import com.opensymphony.oscache.general.GeneralCacheAdministrator;

public class BaseCache extends GeneralCacheAdministrator {
 // 过期时间(单位为秒);
 private int refreshPeriod;

 // 关键字前缀字符;
 private String keyPrefix;

 private static final long serialVersionUID = -4397192926052141162L;

 public BaseCache(String keyPrefix, int refreshPeriod) {
  super();
  this.keyPrefix = keyPrefix;
  this.refreshPeriod = refreshPeriod;
 }

 // 添加被缓存的对象;
 public void put(String key, Object value) {
  this.putInCache(this.keyPrefix + "_" + key, value);
 }

 // 删除被缓存的对象;
 public void remove(String key) {
  this.flushEntry(this.keyPrefix + "_" + key);
 }

 // 删除所有被缓存的对象;
 public void removeAll(Date date) {
  this.flushAll(date);
 }

 public void removeAll() {
  this.flushAll();
 }

 // 获取被缓存的对象;
 public Object get(String key) throws Exception {
  try {
   return this.getFromCache(this.keyPrefix + "_" + key,
     this.refreshPeriod);
  } catch (NeedsRefreshException e) {
   this.cancelUpdate(this.keyPrefix + "_" + key);
   throw e;
  }

 }

}

2.  CacheManager.java  管理器

package com.yanek.demo.cache.oscache;

public class CacheManager { 
   
    private BaseCache newsCache; 
 
     
    private static CacheManager instance; 
    private static Object lock = new Object(); 
     
    public CacheManager() { 
        //这个根据配置文件来，初始BaseCache而已; 
        newsCache = new BaseCache("news",1800);      
    } 
     
    public static CacheManager getInstance(){ 
        if (instance == null){ 
            synchronized( lock ){ 
                if (instance == null){ 
                    instance = new CacheManager(); 
                } 
            } 
        } 
        return instance; 
    } 
 
    public void putNews(News news) { 
        // TODO 自动生成方法存根 
        newsCache.put(news.getId(),news); 
    } 
 
    public void removeNews(String newsID) { 
        // TODO 自动生成方法存根 
        newsCache.remove(newsID); 
    } 
 
    public News getNews(String newsID) { 
        // TODO 自动生成方法存根 
        try { 
            return (News) newsCache.get(newsID); 
        } catch (Exception e) { 
            // TODO 自动生成 catch 块 
            System.out.println("getNews>>newsID["+newsID+"]>>"+e.getMessage()); 
           // News news = new News(newsID); 
           
            News news = new News(newsID,"aaa","bbb");
            this.putNews(news); 
            return news; 
        } 
    } 
 
    public void removeAllNews() { 
        // TODO 自动生成方法存根 
        newsCache.removeAll(); 
    } 
 
} 

3. News.java  缓存的对象

package com.yanek.demo.cache.oscache;

public class News {

 private String id;

 private String title;

 private String content;

 
 public News(String id, String title, String content) {
  super();
  this.id = id;
  this.title = title;
  this.content = content;
 }

 public String getContent() {
  return content;
 }

 public void setContent(String content) {
  this.content = content;
 }

 public String getId() {
  return id;
 }

 public void setId(String id) {
  this.id = id;
 }

 public String getTitle() {
  return title;
 }

 public void setTitle(String title) {
  this.title = title;
 }

}

4. TestCache.java 测试

package com.yanek.demo.cache.oscache;

public class TestCache {

 /**
  * @param args
  */
 public static void main(String[] args) {

  
  CacheManager cm=CacheManager.getInstance();
  News n1=new News("1","111","111");
  cm.putNews(n1);
  News n1_c=cm.getNews("1");
  System.out.println("c1:"+n1_c.getContent());
  
  News n2=new News("1","111","222");
  cm.putNews(n2);
  System.out.println("c1:"+cm.getNews("1").getContent());
  
  cm.removeNews("1");
  
  System.out.println("c1:"+cm.getNews("1").getContent());
  
  BaseCache countCache = new BaseCache("count",1800);
  
  countCache.put("1100454", 10);
  countCache.put("1100455", 11);
  countCache.put("1100456", 3);
  
  try {
   Integer cachedCount = (Integer)countCache.get("1100454");

   System.out.println("cachedCount:"+cachedCount);
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  
  
  
 }

}