Question

让我们假设我们有以下实体：

@Entity
@DiscriminatorColumn(name="Type")
@Inheritance(strategy=InheritanceType.Joined)
public abstract class Employee extends Persistable<Long> {

    private String firstName;
    private String lastName;

    //getters, setters
}

@Entity
@DiscriminatorValue("S")
public class SalariedEmployee extends Employee {
            //various fields
}

@Entity
@DiscriminatorValue("C")
public class ContractEmployee extends Employee {
            //various fields
}

@Entity
@DiscriminatorValue("H")
public class HourlyEmployee extends Employee {
            //various fields
}

和Repository

public interface EmployeeRepository implements PagingAndSortingRepository<Employee, Long> {
}

我如何搜索查询可以说＆＃34;带给我所有不是HourlyEmployees＆＃34;的员工。显然我会要求对它们进行分页/排序，所以我可能不能findAll();并且如果我没有弄错的话，只删除页面集合中的条目。

Answer 1

请参阅JPQL类型运算符：

http://en.wikibooks.org/wiki/Java_Persistence/JPQL#JPQL_special_operators

JPA 2.0规范（第4.6.17.4节）给出了以下用法示例：

SELECT e
FROM Employee e
WHERE TYPE(e) IN (Exempt, Contractor)

SELECT e
FROM Employee e
WHERE TYPE(e) IN (:empType1, :empType2)

SELECT e
FROM Employee e
WHERE TYPE(e) IN :empTypes

SELECT TYPE(e)
FROM Employee e
WHERE TYPE(e) <> Exempt

Spring数据 - 按类型继承搜索

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