java Spring @Cacheable 仍然执行复杂的键
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Spring @Cacheable with complex keys still executed
提问by checklist
I have the following for the usage of a @Cacheable in spring (3.1):
对于在 spring (3.1) 中使用 @Cacheable，我有以下几点：
spring:
春天：
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oauth="http://www.springframework.org/schema/security/oauth2"
xmlns:sec="http://www.springframework.org/schema/security"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:cache="http://www.springframework.org/schema/cache"
xmlns:mongo="http://www.springframework.org/schema/data/mongo"
xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/security/oauth2
http://www.springframework.org/schema/security/spring-security-oauth2-1.0.xsd
http://www.springframework.org/schema/data/mongo
http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd">
<cache:annotation-driven />
<bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager" p:cache-manager-ref="ehcache" />
<!-- Ehcache library setup -->
<bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"
p:config-location="classpath:ehcache.xml" />
Maven:
马文：
<dependency>
<groupId>net.sf.ehcache</groupId>
<artifactId>ehcache-core</artifactId>
<version>2.5.3</version>
</dependency>
The to be cached method:
要缓存的方法：
@Cacheable(value="cahceName", key="concat(#param1).concat(‘-').concat(#param2)")
public String cachedMethod(String param1,String param2)
Alas, when I debug the code, I see that the cached method gets called more than once even when param1 and param2 are the same (i.e the cahce is not used).
唉，当我调试代码时，我发现即使 param1 和 param2 相同（即未使用 cahce），缓存方法也被多次调用。
Any ideas?
有任何想法吗？
回答by Biju Kunjummen
The key does not appear correct -
密钥显示不正确 -
You may have meant - @Cacheable(value="cacheName", key="#param1.concat(‘-').concat(#param2)")
你可能是说—— @Cacheable(value="cacheName", key="#param1.concat(‘-').concat(#param2)")
Further, if the compilation is done without debug information, the param1, param2 argument names will not be available to expression evaluator. Instead you can refer to them using p0, p1 etc this way:
此外，如果在没有调试信息的情况下完成编译，则表达式评估器将无法使用 param1、param2 参数名称。相反，您可以通过以下方式使用 p0、p1 等来引用它们：
@Cacheable(value="cahceName", key="#p0.concat('-').concat(#p1)")
@Cacheable(value="cahceName", key="#p0.concat('-').concat(#p1)")
Update:
更新：
I have a one page test here which demonstrates how this works - https://gist.github.com/3315275
我在这里有一个一页测试，它演示了这是如何工作的 - https://gist.github.com/3315275
回答by Leszek Jasek
In my case, the problem was caused by using the wrong configuration of the cache provider (Caffeine):
就我而言，问题是由于使用缓存提供程序 ( Caffeine)的错误配置引起的：
@Bean
public Caffeine<Object, Object> caffeineCacheBuilder() {
return Caffeine.newBuilder()
.initialCapacity(100)
.maximumSize(1000)
.expireAfterAccess(10, TimeUnit.MINUTES)
.weakKeys(); // cause problems when concatenated keys used
}
As the docs says, weakKeys()method:
正如文档所说，weakKeys()方法：
Specifies that each key (not value) stored in the cache should be wrapped in a WeakReference (by default, strong references are used).
Warning:when this method is used, the resulting cache will use identity ({@code ==}) comparison to determine equality of keys. Its {@link Cache#asMap} view will therefore technically violate the {@link Map} specification (in the same way that {@link IdentityHashMap} does).
指定存储在缓存中的每个键（不是值）都应该包含在 WeakReference 中（默认情况下，使用强引用）。
警告：使用此方法时，生成的缓存将使用标识 ({@code ==}) 比较来确定键的相等性。因此，它的 {@link Cache#asMap} 视图在技术上将违反 {@link Map} 规范（与 {@link IdentityHashMap} 相同）。
