使用Spring Data 4 JPA的自定義保存方法

Question

我知道春天的數據使用SimpleJpaRepository作為實施JpaRepository 。 我期待為某些存儲庫覆蓋其save方法。 有什么方法不意味着替換我所有存儲庫的默認實現？

我已經嘗試在MyEntityJpaImpl類中擴展SimpleJpaRepository ，但是它沒有提供適合自動裝配的默認構造函數。

編輯：

這是我要自動接線的課程

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);
            }
    }   
}

和最相關的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

您可以通過在擴展JpaRepository的接口內編寫自己的方法來提供自定義實現

有兩種方法可以做到這一點：

1。 您可以使用@Query批注並在其中編寫查詢。

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

2。 您可以使用NamedQuery並引用您的方法。

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

Answer 2

spring-data的文檔中包含一些示例，可以完全解決您的問題。

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

例子30.覆蓋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:

例子31.定制的倉庫接口

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

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