spring與redis集成之aop整合方案

 

java使用redis緩存能夠使用jedis框架,jedis操做簡單,沒有什麼複雜的東西須要學習,網上資料不少,隨便看看就會了.

將spring與redis緩存集成,其實也是使用jedis框架,只不過spring對它進行了一層封裝,並將這層封裝庫命名爲spring-data-redis.

下面將要使用spring-data-redis與jedis的jar包,並經過spring的aop功能,將redis緩存無縫無侵入的整合進來.

1.先下載好依賴包

 

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>4.1.1.RELEASE</version>
</dependency>
<!-- 還有spring的其它包,這裏不一一貼出-->

 

 

<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-redis</artifactId>
    <version>1.4.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>2.6.0</version>
</dependency>

2.再配置spring文件

 

 

   <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
    <property name="minIdle" value="${redis.minIdle}" />
       <property name="maxIdle" value="${redis.maxIdle}" />
       <property name="maxTotal" value="${redis.maxActive}" />
       <property name="maxWaitMillis" value="${redis.maxWait}" />
       <property name="testOnBorrow" value="${redis.testOnBorrow}" />
   </bean>

   <bean id="jedisConnFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
       <property name="hostName" value="${redis.host}" />
       <property name="port" value="${redis.port}" />
       <property name="password" value="${redis.password}" />
       <property name="usePool" value="true" />
       <property name="poolConfig" ref="poolConfig" />
   </bean>

<!-- redis template definition -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
    <property name="connectionFactory" ref="jedisConnFactory" />
    <property name="keySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property>
    <property name="valueSerializer">
        <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer" />
    </property>
    <property name="hashKeySerializer">
       <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
    </property>
    <property name="hashValueSerializer">
       <bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
    </property>
</bean>

3.開始編寫aop代碼

 

3.1 聲明兩個註解類,用於定義哪些方法將使用緩存

 

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface Cacheable {

    public enum KeyMode{
        DEFAULT,    //只有加了@CacheKey的參數,才加入key後綴中
        BASIC,      //只有基本類型參數,才加入key後綴中,如:String,Integer,Long,Short,Boolean
        ALL;        //全部參數都加入key後綴
    }

    public String key() default "";     //緩存key
    public KeyMode keyMode() default KeyMode.DEFAULT;       //key的後綴模式
    public int expire() default 0;      //緩存多少秒,默認無限期
}

 

 

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.PARAMETER})
public @interface CacheKey {}

3.2 建立一個Aop攔截器的處理類,用於攔截加了@Cacheable的方法

 

@Aspect
@Component
public class CacheableAop {

    @Autowired private RedisTemplate redisTemplate;

    @Around("@annotation(cache)")
    public Object cached(final ProceedingJoinPoint pjp,Cacheable cache) throws Throwable {

        String key=getCacheKey(pjp, cache);
        ValueOperations<String, Object> valueOper=redisTemplate.opsForValue();
        Object value=valueOper.get(key);    //從緩存獲取數據
        if(value!=null) return value;       //若是有數據,則直接返回

        value = pjp.proceed();      //跳過緩存,到後端查詢數據
        if(cache.expire()<=0) {      //若是沒有設置過時時間,則無限期緩存
            valueOper.set(key, value);
        } else {                    //不然設置緩存時間
            valueOper.set(key, value,cache.expire(),TimeUnit.SECONDS);
        }
        return value;
    }

    /**
     * 獲取緩存的key值
     * @param pjp
     * @param cache
     * @return
     */
    private String getCacheKey(ProceedingJoinPoint pjp,Cacheable cache) {

        StringBuilder buf=new StringBuilder();
        buf.append(pjp.getSignature().getDeclaringTypeName()).append(".").append(pjp.getSignature().getName());
        if(cache.key().length()>0) {
            buf.append(".").append(cache.key());
        }

        Object[] args=pjp.getArgs();
        if(cache.keyMode()==KeyMode.DEFAULT) {
            Annotation[][] pas=((MethodSignature)pjp.getSignature()).getMethod().getParameterAnnotations();
            for(int i=0;i<pas.length;i++) {
                for(Annotation an:pas[i]) {
                    if(an instanceof CacheKey) {
                        buf.append(".").append(args[i].toString());
                        break;
                    }
                }
            }
        } else if(cache.keyMode()==KeyMode.BASIC) {
            for(Object arg:args) {
                if(arg instanceof String) {
                    buf.append(".").append(arg);
                } else if(arg instanceof Integer || arg instanceof Long || arg instanceof Short) {
                    buf.append(".").append(arg.toString());
                } else if(arg instanceof Boolean) {
                    buf.append(".").append(arg.toString());
                }
            }
        } else if(cache.keyMode()==KeyMode.ALL) {
            for(Object arg:args) {
                buf.append(".").append(arg.toString());
            }
        }

        return buf.toString();
    }
}

4.使用緩存示例

 

@Service
@Transactional
public class DemoServiceImpl implements DemoService {

    @Autowired private DemoDao demoDao;

    public List<Demo> findAll() {
        return demoDao.findAll();
    }

    /*
        對get()方法配置使用緩存,緩存有效期爲3600秒,緩存的key格式爲:{package_name}.DemoServiceImpl.get
        同時爲參數配置了@CacheKey後,表示此參數的值將作爲key的後綴,此例的key,最終是:{package_name}.DemoServiceImpl.get.{id}
        能夠爲多個參數配置@CacheKey,攔截器會調用參數的toString()作爲key的後綴
        若配置多個@CacheKey參數,那麼最終的key格式爲:{package_name}.{class_name}.{method}.{arg1}.{arg2}.{...}
     */
    @Cacheable(expire=3600)
    public Demo get(@CacheKey String id) {
        return demoDao.get(id);
    }

    public Demo getByName(String name) {
        return demoDao.getByName(name);
    }
}

 

• 若爲名稱相同的方法配置緩存,能夠在@Cacheable中加入key屬性,追加額外的key後綴
• @Cacheable還有一個KeyMode屬性,用於配置哪些參數能夠追加到key後綴中,默認取值 DEFAULT:表示只有加了@CacheKey的參數才能追加到key後綴BASIC:自動將基本類型追加到key後綴,而無需再配置@CacheKeyALL:自動將全部參數追加到lkey後綴,而無需再配置@CacheKey