CODEWITHSUNDEEP
javaspring-bootcachingredisehcache
Iti Gupta
Iti Gupta

Reputation: 189

Accessing returned data by method in spring cache

I've a Person which has id and name.

When I search by Id the method returned the Person Object and I want to make name as cache key but the returned data is not accessible in key tag of Cacheable annotation but the name is accessible in unless tag. 

@Cacheable(value = "Cache", key = "#result.name", unless="#result.name == 'Foo'")
public Person getById(String id){}

If I use key = "#result.name" it gives me exception :

EL1007E: Property or field 'name' cannot be found on null

What am I missing, How can I access returned data from method in key tag?

Upvotes: 5

Views: 5463

Answers (2)

Yogi
Yogi

Reputation: 1895

Cache keys should generated from method parameter on which you are applying caching and you cache result of method.

Working code will be:

@Cacheable(value = "personCache", key = "#id", unless="#person.name == 'Foo'")
public Person getById(String id){

    Person person = data initialization logic here;
    return person;
}

For more information on Caching go through this link.

For some best practice follow this blog.

Upvotes: 0

msp
msp

Reputation: 3364

In your use case this is not possible since the cache key gets generated from the parameter you're passing to the method and that's String id. Therefore Spring tries to extract the name parameter from the String. Which is not possible.

Even if it was possible to use the name of the result as cache key the cache wouldn't work as you're querying by id.

Upvotes: 4

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