java 为 Spring 的 @Cacheable 注释定义键的最佳方法是什么
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What is the best way of defining key for @Cacheable annotation for Spring
提问by BITSSANDESH
If I am defining a ehcache for a method which doesn't have any parameter.
如果我为没有任何参数的方法定义 ehcache。
But in my use case I needs to access the my built cache through it's key.
但是在我的用例中，我需要通过它的键来访问我构建的缓存。
So please provide me the better way of assigning key on it.
所以请为我提供更好的分配密钥的方法。
Follow is my code:
以下是我的代码：
@Override
@Cacheable(value = "cacheName", key = "cacheKey")
public List<String> getCacheMethod() throws Exception{
P.S. I am getting the following error when I am trying to access this method from somewhere else.
PS 当我尝试从其他地方访问此方法时，出现以下错误。
org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Field or property 'cacheKey' cannot be found on object of type 'org.springframework.cache.interceptor.CacheExpressionRootObject'
org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): 在“org.springframework.cache.interceptor.CacheExpressionRootObject”类型的对象上找不到字段或属性“cacheKey”
回答by Manuel Jordan
The method has no parameter, therefore there is no a way to use a parameter/argument as a default key, and you can't use "static text" as a Key, you could do the following:
该方法没有参数，因此无法使用参数/参数作为默认键，并且您不能使用“静态文本”作为键，您可以执行以下操作：
Declare the following
声明以下内容
public static final String KEY = "cacheKey";
- must be
public - must be
staticandfinal
- 必须是
public - 必须是
static和final
Then
然后
@Override
@Cacheable(value = "cacheName", key = "#root.target.KEY")
public List<String> getCacheMethod() throws Exception{
Done
完毕
回答by Rafik BELDI
Please take a look at this spring doc.
请看一下这个spring 文档。
the key refers to the arguments of your method, you are having SpelEvaluationExceptionbecause cachekeyisn't among your method arguments.
键是指您的方法的参数，SpelEvaluationException因为cachekey不在您的方法参数中。
回答by Nikolai Shevchenko
In simple cases you can use an easier way: @Cacheable(key = "#root.methodName"), and the key would be equal to annotated method's name
在简单的情况下，您可以使用更简单的方法：@Cacheable(key = "#root.methodName")，并且键将等于带注释的方法的名称
