Does Spring Data JPA have any way to count entites using method name resolving?

Question

As of Spring Data 1.7.1.RELEASE you can do it with two different ways,

1. The new way, using query derivation for both count and delete queries. Read this, (Example 5). Example,

    public interface UserRepository extends CrudRepository<User, Integer> {
        long countByName(String name);
    }

2. The old way, Using @Query annotation.
   Example,

    public interface UserRepository extends CrudRepository<User, Integer> {
        @Query("SELECT COUNT(u) FROM User u WHERE u.name=?1")
        long aMethodNameOrSomething(String name);
    }

or using @Param annotation also,

public interface UserRepository extends CrudRepository<User, Integer> {
    @Query("SELECT COUNT(u) FROM User u WHERE u.name=:name")
    long aMethodNameOrSomething(@Param("name") String name);
}

Check also this so answer.

As long as you do not use 1.4 version, you can use explicit annotation:

example:

@Query("select count(e) from Product e where e.area.code = ?1")
long countByAreaCode(String code);

JpaRepository also extends QueryByExampleExecutor. So you don't even need to define custom methods on your interface:

public interface UserRepository extends JpaRepository<User, Long> {
    // no need of custom method
}

And then query like:

User probe = new User();
u.setName = "John";
long count = repo.count(Example.of(probe));

Working example

@Repository
public interface TenantRepository extends JpaRepository< Tenant, Long > {
    List<Tenant>findByTenantName(String tenantName,Pageable pageRequest);
    long countByTenantName(String tenantName);
}

Calling from DAO layer

@Override
public long countByTenantName(String tenantName) {
    return repository.countByTenantName(tenantName);
}

This feature has been added in version 1.4 M1

Apparently it is implemented now DATAJPA-231

According to Abel, after the version 1.4 (tested in version 1.4.3.RELEASE) is possible doing this way:

public long countByName(String name);