Annotation实现缓存

设计：
1. 定义一个接口
2. 定义一个实现类
3. 定义一个Annotation
4. 定义一个Annotation解析器
5. 定义一个Proxy
6. 定义一个proxy来代理接口实现。

代码如下:

package org.frame.base.annotation.intercept;

public interface TestI { 
	public int add(int a,int b);
	public int xx(int a);
}

实现类

public class Test implements TestI{
	public int add(int a,int b){
		return a+b;
	}
	
	@EhCache(key="cacheKey")
	public int xx(int a){
		return a;
	}
}

Annotation类

package org.frame.base.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Annotation indicating that a method (or all the methods on a class) can be cached.
 *
 * <p>The method arguments and signature are used for computing the key while the
 * returned instance is used as the cache value.
 *
 * @author xxx
 * @since 1.0
 */
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME) 
public @interface EhCache {

	/**
	 * Name of the caches in which the update takes place.
	 * <p>May be used to determine the target cache (or caches), matching the
	 * qualifier value (or the bean name(s)) of (a) specific bean definition.
	 */
	String[] value() default "";
	
	/**
	 * Spring Expression Language (SpEL) attribute for computing the key dynamically.
	 * <p>Default is "", meaning all method parameters are considered as a key.
	 */
	String key() default "";
	
	/**
	 * Spring Expression Language (SpEL) attribute used for conditioning the method caching. 
	 * <p>Default is "", meaning the method is always cached.
	 */
	String condition() default "";
}

Annotation解析类

package org.frame.base.annotation;

import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;

import org.springframework.util.Assert;

/**
 * EhCache的操作对象
 *   
 *
 */
public class EhCacheOperator {

	private String name;
	private Set<String> cacheNames = Collections.emptySet();//value 
	private String key = "";//key
	private String condition = "";//condition
	public Set<String> getCacheNames() {
		return cacheNames;
	}
	public void setCacheNames(String[] cacheNames) {
		Assert.notEmpty(cacheNames);
		this.cacheNames = new LinkedHashSet<String>(cacheNames.length);
		for (String string : cacheNames) {
			this.cacheNames.add(string);
		}
	}
	public String getKey() {
		return key;
	}
	public void setKey(String key) {
		this.key = key;
	}
	public String getCondition() {
		return condition;
	}
	public void setCondition(String condition) {
		this.condition = condition;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

代理类

package org.frame.base.annotation.intercept;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.util.Collection;

import org.frame.base.annotation.CachePaserImpl;
import org.frame.base.annotation.EhCacheOperator;
import org.frame.base.annotation.support.EhCacheAnnotationParser;
import org.frame.base.cache.LocalCacheManager;

/**
 * 在代理层使用缓存 
 *
 */
public class ProxyHandler implements InvocationHandler {

	EhCacheAnnotationParser ehcacheParser = new EhCacheAnnotationParser();
	LocalCacheManager cacheManager = LocalCacheManager.getInstance();
	
	private Object target;
	  
	public void setTarget(Object o){
		  this.target = o;
    }
	
	public ProxyHandler(Object target){
		this.target = target;
	}
	
	@Override
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		Object result = null;
		Collection<EhCacheOperator> ehcacheOperators = ehcacheParser.getCacheOperations(method, target.getClass());
		if(ehcacheOperators == null || ehcacheOperators.isEmpty()){
			result = method.invoke(target, args);
		}else{
			for(EhCacheOperator ehcacheOperator:ehcacheOperators ){
				if(ehcacheOperator.getName().equals(CachePaserImpl.EHCACHE)){//ehcache 注解
					Object cacheObj = cacheManager.get(ehcacheOperator.getKey());
					if(cacheObj == null){
						result = method.invoke(target, args);
						if(result != null){
							cacheManager.put(ehcacheOperator.getKey(), result);
						}
					}else{
						result = cacheObj;
					}
				}
			} 
		}
		
		return result;
	}
	 
}

代理接口实现类

package org.frame.base.annotation.support;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

import org.frame.base.annotation.intercept.ProxyHandler;
import org.springframework.beans.factory.FactoryBean;

/**
 * 代理某个对象的所有接口 
 *
 */
public class EhCacheFactoryBean implements FactoryBean{
	   
	private Object target;
	
	private Object proxyObj = null;
	
	private Class<?>[] interfaceClass = null;
	
	public void setTarget(Object target){
		this.target = target;
	} 
	
	/**
	 * 接口反映返回对象
	 *    1. serviceInterface 接口
	 *    2. target 目标地址，IP:端口
	 * @throws Exception
	 */
	public void init() throws Exception {
		interfaceClass = target.getClass().getInterfaces();
		InvocationHandler handler = new ProxyHandler(target);
		proxyObj = Proxy.newProxyInstance(target.getClass().getClassLoader(),
				interfaceClass, handler);
	}

	@Override
	public Object getObject() throws Exception { 
		return proxyObj;
	}

	@SuppressWarnings("unchecked")
	@Override 
	public Class getObjectType() { 
		return interfaceClass[0];
	}

	@Override
	public boolean isSingleton() { 
		return true;
	}

}

配置如下:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans default-autowire="byName">
	<!-- annotation intercept-->
	<bean id="testIano"
		class="org.frame.base.annotation.support.EhCacheFactoryBean" init-method="init"> 
		<property name="target">
			<ref bean = "testI"/>
		</property> 
	</bean>
	
	<!-- 原始结构 -->
	<bean id="testI" class ="org.frame.base.annotation.intercept.Test"/>
	
</beans>

测试代码如下:

ApplicationContext cxt  = new ClassPathXmlApplicationContext(new String[]{"annotation/ano.xml"});
		//TestI testI = (TestI) cxt.getBean("testI");
		TestI testI = (TestI) cxt.getBean("testIano");
		int a = 10;
		int b = 11;
		System.out.println(testI.add(a, b));
		System.out.println(testI.add(a, b));
		System.out.println(testI.xx(a));
		System.out.println(testI.xx(a));

可以看到配置了Ehcache的方法实现了缓存功能。

评论

2 楼 a123159521 2014-04-10  

ehcacheOperators

至尊宝_唯一 写道

EhCacheAnnotationParser ehcacheParser = new EhCacheAnnotationParser();

这个Parser类是哪儿来的啊?

应该是忘记上传了， 这个类是解析类，从名字就看的出来。

1 楼 至尊宝_唯一 2014-04-08  

EhCacheAnnotationParser ehcacheParser = new EhCacheAnnotationParser();

这个Parser类是哪儿来的啊?