oscache 对象缓存

转自 http://benx.iteye.com/blog/606091

Java代码

一、对象缓存
1、Cache操作类
import java.util.Date;
import com.opensymphony.oscache.base.NeedsRefreshException;
import com.opensymphony.oscache.general.GeneralCacheAdministrator;
public class BaseCache extends GeneralCacheAdministrator {
    private int refreshPeriod; //过期时间(单位为秒);
    private String keyPrefix; //关键字前缀字符;
    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{
            returnthis.getFromCache(this.keyPrefix+"_"+key,this.refreshPeriod);
        } catch (NeedsRefreshException e) {
            this.cancelUpdate(this.keyPrefix+"_"+key);
            throw e;
        }
    }
}

2、Cache管理类
public class CacheManager {
    private BaseCache newsCache;
    private static CacheManager instance;
    private static Object lock = new Object();
    private CacheManager() {
        //这个根据配置文件来，初始BaseCache而已;
        newsCache = new BaseCache("news",120);
    }
    public static CacheManager getInstance(){
        if (instance == null){
            synchronized( lock ){
                if (instance == null){
                    instance = new CacheManager();
                }
            }
        }
        return instance;
    }
    public void putUser(User news) { newsCache.put(news.getId()+"",news);     }
    public void removeUser(String newsID) {  newsCache.remove(newsID);      }
    public User getUser(int newsID) {
        try {
            return (User) newsCache.get(newsID+"");
        } catch (Exception e) {
            System.out.println("getNews>>newsID["+newsID+"]>>"+e.getMessage());
            User news = new User(newsID);
            this.putUser(news);
            return news;
        }
    }
    public void removeAllNews() {
        newsCache.removeAll();
    }
}

3、对象Bean
public class User {
    private int id;
    private String name;
    private String sex;
    private int age;
    private Date accessTime; public User(int id) {
       super();
       this.id = id;
       this.accessTime = new Date(System.currentTimeMillis());
    }
    public String toString() {
       return "User info is : id=" + id + "  accessTime="
              + accessTime.toString();
    }
    public User(String name, String sex, int age) {
       super();
       this.name = name;
       this.sex = sex;
       this.age = age;
    }
    public User() {
    }
    public int getAge() {
       return age;
    }
    public void setAge(int age) {
       this.age = age;
    }
    public String getName() {
       return name;
    }
    public void setName(String name) {
       this.name = name;
    }
    public String getSex() {
       return sex;
    }
    public void setSex(String sex) {
       this.sex = sex;
    }
    public int getId() {
       return id;
    }
    public void setId(int id) {
       this.id = id;
    }
    public Date getAccessTime() {
       return accessTime;
    }
    public void setAccessTime(Date accessTime) {
       this.accessTime = accessTime;
    }
}

4、测试类
public class TestObjectCache {
    public static void main(String[] args) {
       CacheManager cm=CacheManager.getInstance();

       TestObjectCache test=new TestObjectCache();
       test.print(cm);
    }

    public void print(CacheManager cm){
       User user=null;
       for (int i = 0; i < 1000; i++) {
           user=cm.getUser(100);
           System.out.println("<<"+i+">>: "+user);
           if(i==10){
              //删除缓存id的对象
              cm.removeUser(100+"");
           }
           if(i==20){
              //删除所有缓存的对象
              cm.removeAllNews();
           }
           // 睡眠部分
           try {
              Thread.sleep(30000);
           } catch (Exception e) {
           }
       }
    }
}