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import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* 方法注解
*
*/
@Retention(RetentionPolicy.RUNTIME)
// @Target(ElementType.METHOD)
public @interface MethodAnnotation {
/**
* 缓存中key的前缀
*
* @return
*/
public String keyedPrifix();
/**
* 保留的前缀名称，不会被放进MD5中的
*
* @return
*/
String keepPrifix() default "";
}
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* 模型层对象注解类
*/
@Retention(RetentionPolicy.RUNTIME)
public @interface ModelAnnotation {
/**
* 属性对应的表中的字段名称
* @return
*/
public String filedName();
}
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import cn.dfinder.dps.common.cache.CacheProxy;
/**
* 实体模型和数据库表字段映射关系工具类 利用反射机制，根据字段名称查找模型类中字段的注解 读取注解的fieldName值找到数据库中对应的字段名称
*
*/
public class AnnotationUtils {
private static final Log logger = LogFactory.getLog(CacheProxy.class);
@SuppressWarnings("rawtypes")
/**
* @param clazz 类
* @param fieldName 类中属性的名称
* @return 表中字段的名称
*/
public static String getFiledName(Class clazz, String fieldName) {
String name = null;
try {
Field field = clazz.getDeclaredField(fieldName);
ModelAnnotation annotation = field
.getAnnotation(ModelAnnotation.class);
name = annotation.filedName();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
}
return name;
}
/**
* 得到方法的上定义的放入缓存中的前缀字符串
*
* @param clazz
* @param methodName
* @return
*/
public static String getKeyedPrefix(Method method) {
String keyedPrefix = null;
try {
MethodAnnotation annotation = method
.getAnnotation(MethodAnnotation.class);
if (annotation == null) {
// 记录没有注解的方法
logger.info("No Annotation Method:" + method);
} else {
keyedPrefix = annotation.keyedPrifix();
}
} catch (SecurityException e) {
e.printStackTrace();
}
return keyedPrefix;
}
public static String getKeepPrefix(Method method) {
String keepPrefix = null;
try {
MethodAnnotation annotation = method
.getAnnotation(MethodAnnotation.class);
if (annotation != null) {
keepPrefix = annotation.keepPrifix();
}
} catch (SecurityException e) {
e.printStackTrace();
}
return keepPrefix;
}
}
@ModelAnnotation(filedName="数据库字段名")
private String 自定义属性名;
数据库字段名 = AnnotationUtils.getFiledName(
对应的类名.class, "自定义属性名");
@MethodAnnotation(keyedPrifix = "缓存对应key")
public 返回值 方法名(String 参数 );
调用相应的dao接口时
在调用该接口的类的构造函数中得到该实例
@Component("indexCommodityDaoFactory")
public class IndexCommodityDaoFactory {
/**
* 创建商品分类的数据访问对象
* @return
*/
public static 调用的接口dao 方法名() {
调用的接口dao 名称= (调用的接口dao) new CacheProxy()
.bind(new 调用的接口dao);
return 名称;
}
}
public class CacheProxy implements InvocationHandler {
private static final Log logger = LogFactory.getLog(CacheProxy.class);
/**
* 默认30分钟在缓存中失效
*/
private static final int DEFAULT_TTL = 30 * 60;
private int expireTime = DEFAULT_TTL;
/**
* memcached客户端访问接口
*/
private JedisClient cache;
Object originalObject;
public Object bind(Object originalObject) {
this.originalObject = originalObject;
return Proxy.newProxyInstance(originalObject.getClass()
.getClassLoader(), originalObject.getClass().getInterfaces(),
this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
init();
String keyedPrifix = AnnotationUtils.getKeyedPrefix(method);
String keepPrifix = AnnotationUtils.getKeepPrefix(method);
Object cacheData = null;
// 判断是否使用的cache
boolean useCache = CacheProcessor.useCache();
if (useCache) {
cacheData = fetchFromCache(args, keyedPrifix, keepPrifix);
}
if (cacheData == null) {
cacheData = method.invoke(originalObject, args);
// put it into cache
if (useCache && cacheData != null) {
putIntoCache(cacheData, args, keyedPrifix, keepPrifix);
}
}
return cacheData;
}
private void init() {
cache = JedisClientFactory.getClient();
Integer ttl = CacheProcessor.getExpiretime();
if (ttl != null && ttl > 0) {
expireTime = ttl;
}
}
private String keys(Object[] args, String prifix) {
List<String> values = new ArrayList<String>();
if (args != null) {
for (Object arg : args) {
if (arg != null) {
values.add(arg.toString() + "_");
}
}
}
// 将当前类信息编译进key，防止同一个接口，不同实现产生相同的key值
String className = originalObject.getClass().getName();
values.add(className + "_");
String keys = CachedKeyUtil.listStrToKey(prifix, values);
return keys;
}
/**
* 从缓存中取数据
*
* @param args
* @param prifix
* @return
*/
private Object fetchFromCache(Object[] args, String keyedPrifix,
String keepPrifix) {
String keys = keys(args, keyedPrifix);
if (keepPrifix != null && keepPrifix.isEmpty() == false) {
keys = keepPrifix + keys;
}
// 从cache中取数据
Object obj = null;
if (keys != null) {
long start = System.currentTimeMillis();
obj = cache.get(keys);
long end = System.currentTimeMillis();
long deltTime = end - start;
boolean hit = false;
if (obj != null) {
hit = true;
}
logger.info("fetch data from cache,key=" + keys + ",coast="
+ deltTime + "ms,hit=" + hit + "");
}
return obj;
}
/**
* 将数据放入缓存
*
* @param value
* @param args
* @param prifix
*/
private void putIntoCache(Object value, Object[] args, String keyedPrifix,
String keepPrifix) {
String keys = keys(args, keyedPrifix);
if (keepPrifix != null && keepPrifix.isEmpty() == false) {
keys = keepPrifix + keys;
}
cache.set(keys, value, expireTime);
}
}
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原文地址：http://www.cnblogs.com/yanduanduan/p/5057309.html
