Question

我知道Spring Data使用SimpleJpaRepository作为JpaRepository的实现。我期待覆盖某些存储库的save方法。有什么方法并不意味着替换我所有存储库的默认实现？

我已经尝试在SimpleJpaRepository类中扩展MyEntityJpaImpl，但它没有提供适合自动装配的默认构造函数。

编辑：

以下是我尝试自动装配的课程

public class MyEntityJpaImpl<ClientesCentro, ClientesCentroPK extends Serializable> extends SimpleJpaRepository<ClientesCentro, ClientesCentroPK> implements ExtendedRepository<ClientesCentro, ClientesCentroPK>{

    private JpaEntityInformation<ClientesCentro, ClientesCentroPK> entityInformation;
    @PersistenceContext
    private EntityManager em;
    private Class<ClientesCentro> clazz;

    public MyEntityJpaImpl(Class<ClientesCentro> domainClass, EntityManager em) {       

        this((JpaEntityInformation<ClientesCentro, ClientesCentroPK>) JpaEntityInformationSupport.getMetadata(domainClass, em), em);
        this.clazz = domainClass;
    }

    public MyEntityJpaImpl(JpaEntityInformation<ClientesCentro, ClientesCentroPK> jpaEntityInformation, EntityManager entityManager) {
        super((JpaEntityInformation<ClientesCentro, ClientesCentroPK>) jpaEntityInformation, entityManager);
        this.entityInformation =  jpaEntityInformation;
        this.clazz = this.entityInformation.getJavaType();
        this.em = entityManager;
    }

    public void refresh() {

    }

    @Transactional
    @Override
    public <S extends ClientesCentro> S save(S entity) {
            System.out.println("Hello world!");

            if (entityInformation.isNew((ClientesCentro) entity)) {
                em.persist(entity);
                return entity;
            } else {
                return em.merge(entity);
            }
    }   
}

最相关的stacktrace部分：

Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.xxxyyy.erp.dal.repository.domain.MyEntityJpaImpl]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.xxxyyy.erp.dal.repository.domain.MyEntityJpaImpl.<init>()
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:85)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1094)
    ... 55 common frames omitted
Caused by: java.lang.NoSuchMethodException: com.xxxyyy.erp.dal.repository.domain.MyEntityJpaImpl.<init>()
    at java.lang.Class.getConstructor0(Unknown Source)
    at java.lang.Class.getDeclaredConstructor(Unknown Source)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:80)
    ... 56 common frames omitted

Answer 1

您可以通过在扩展JpaRepository

的接口内编写自己的方法来提供自定义实现

两种方法：

1。您可以使用@Query注释并在其中编写查询。

@Query("-----Query here------")
public List<Employee> getEmp();

2。您可以使用NamedQuery并为您提供方法参考。

@Query(name="HQL_GET_ALL_EMPLOYEE_BY_ID")
public List<Employee> getEmpByIdUsingNamedQuery(@Param("empId") Long   
empId);

Answer 2

spring-data的文档包含一些示例，可以完全解决您的问题。

https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.single-repository-behavior

示例30.覆盖save（...）的片段

interface CustomizedSave<T> {
  <S extends T> S save(S entity);
}

class CustomizedSaveImpl<T> implements CustomizedSave<T> {

  public <S extends T> S save(S entity) {
    // Your custom implementation
  }
}

The following example shows a repository that uses the preceding repository fragment:

示例31.定制的存储库界面

interface UserRepository extends CrudRepository<User, Long>, CustomizedSave<User> {
}

interface PersonRepository extends CrudRepository<Person, Long>, CustomizedSave<Person> {
}

使用Spring Data 4 JPA自定义保存方法

2 个答案: