将 spring data jpa 与 ninja java 一起使用

Posted 2023-02-19

【中文标题】将 spring data jpa 与 ninja java 一起使用

【英文标题】：use spring data jpa with ninja java

【发布时间】：2017-08-26 21:49:42

【问题描述】：

ninja 是一个很棒的框架，但是来自 spring 背景，我需要将 spring data jpa 与 ninja 一起使用。

我想自动装配一个 JpaRepository 并在 ninja 中使用它。虽然 ninja 使用 Guice Inject。我不断收到没有为我的班级找到的实现。

存储库：

public interface PortalUserRepository extends JpaRepository<PortalUser, Long> 

PortalUser getPortalUserByUsername(String username);

PortalUser getPortalUserByEmail(String email); 

注射

public class SetupDaoV2 

@Inject
PortalUserRepository portalUserRepository;

public void setup() 
    try 
        List<PortalUser> portalUsers = portalUserRepository.findAll();
        if (portalUsers.size() == 0) 
            // Create a new user and save it
            PortalUser portalUser = new PortalUser("lsadjfl", "lsdlfs", "kkk lll",
                    "[e-mail]", "lsdlfss@",
                    "[e-mail]",
                    new Timestamp(System.currentTimeMillis()), Boolean.TRUE,
                    Boolean.TRUE, GenericStatusConstant.ACTIVE, Boolean.TRUE
            );
            portalUserRepository.save(portalUser);
        
    catch (Exception ex)
        ex.printStackTrace();
    

错误

com.google.inject.CreationException：无法创建注入器，请参阅 以下错误：

1) 没有绑定 com.bw.dd.dsl.repository.PortalUserRepository 的实现。

【问题讨论】：

Spring Data JPA 仅适用于 Spring 或 CDI。如果您想将它与 Google Guice 一起使用，您必须自己完成所有的连接和生成工作。

@dunni。必须有一种方法可以将 spring data jpa 移植到 ninja 中，而无需编写整个实现。

好吧，您可以查看 CDI 扩展并尝试将其移植到 Google Guice。但除此之外，没有更简单的可能性。

【参考方案1】：

好吧，我终于不得不实施整个事情。遗憾的是，我无法将 spring data jpa 中的精彩功能移植到 ninja 中。我可以使用弹簧，但用于该项目的办公室政策。

如果有人找到方法，请大家好。

public abstract class JpaRepository<E, K> 

public abstract void create(E entity);

public abstract void edit(E entity) throws Exception;

public abstract void remove(K key) throws IllegalOrphanException, NonexistentEntityException;

public abstract List<E>  findAll();

public abstract E findOne(K key);

public abstract int count();

public class PortalUserRepository extends JpaRepository<PortalUser, Long> 

private EntityManagerFactory emf = null;

public PortalUserRepository() 


public PortalUserRepository(EntityManagerFactory emf) 
    this.emf = emf;


public EntityManager getEntityManager() 
    return emf.createEntityManager();


public void create(PortalUser entity) 
    if (entity.getUserTokens() == null) 
        entity.setUserTokens(new ArrayList<UserToken>());
    
    EntityManager em = null;
    try 
        em = getEntityManager();
        em.getTransaction().begin();
        Collection<UserToken> attachedUserTokens = new ArrayList<UserToken>();
        for (UserToken userTokensUserTokenToAttach : entity.getUserTokens()) 
            userTokensUserTokenToAttach = em.getReference(userTokensUserTokenToAttach.getClass(), userTokensUserTokenToAttach.getId());
            attachedUserTokens.add(userTokensUserTokenToAttach);
        
        entity.setUserTokens(attachedUserTokens);
        em.persist(entity);
        for (UserToken userTokensUserToken : entity.getUserTokens()) 
            PortalUser oldPortalUserOfUserTokensUserToken = userTokensUserToken.getPortalUser();
            userTokensUserToken.setPortalUser(entity);
            userTokensUserToken = em.merge(userTokensUserToken);
            if (oldPortalUserOfUserTokensUserToken != null) 
                oldPortalUserOfUserTokensUserToken.getUserTokens().remove(userTokensUserToken);
                oldPortalUserOfUserTokensUserToken = em.merge(oldPortalUserOfUserTokensUserToken);
            
        
        em.getTransaction().commit();
     finally 
        if (em != null) 
            em.close();
        
    


public void edit(PortalUser entity) throws Exception 
    EntityManager em = null;
    try 
        em = getEntityManager();
        em.getTransaction().begin();
        PortalUser persistentPortalUser = em.find(PortalUser.class, entity.getId());
        Collection<UserToken> userTokensOld = persistentPortalUser.getUserTokens();
        Collection<UserToken> userTokensNew = entity.getUserTokens();
        List<String> illegalOrphanMessages = null;
        for (UserToken userTokensOldUserToken : userTokensOld) 
            if (!userTokensNew.contains(userTokensOldUserToken)) 
                if (illegalOrphanMessages == null) 
                    illegalOrphanMessages = new ArrayList<String>();
                
                illegalOrphanMessages.add("You must retain UserToken " + userTokensOldUserToken + " since its entity field is not nullable.");
            
        
        if (illegalOrphanMessages != null) 
            throw new IllegalOrphanException(illegalOrphanMessages);
        
        Collection<UserToken> attachedUserTokensNew = new ArrayList<UserToken>();
        for (UserToken userTokensNewUserTokenToAttach : userTokensNew) 
            userTokensNewUserTokenToAttach = em.getReference(userTokensNewUserTokenToAttach.getClass(), userTokensNewUserTokenToAttach.getId());
            attachedUserTokensNew.add(userTokensNewUserTokenToAttach);
        
        userTokensNew = attachedUserTokensNew;
        entity.setUserTokens(userTokensNew);
        entity = em.merge(entity);
        for (UserToken userTokensNewUserToken : userTokensNew) 
            if (!userTokensOld.contains(userTokensNewUserToken)) 
                PortalUser oldPortalUserOfUserTokensNewUserToken = userTokensNewUserToken.getPortalUser();
                userTokensNewUserToken.setPortalUser(entity);
                userTokensNewUserToken = em.merge(userTokensNewUserToken);
                if (oldPortalUserOfUserTokensNewUserToken != null && !oldPortalUserOfUserTokensNewUserToken.equals(entity)) 
                    oldPortalUserOfUserTokensNewUserToken.getUserTokens().remove(userTokensNewUserToken);
                    oldPortalUserOfUserTokensNewUserToken = em.merge(oldPortalUserOfUserTokensNewUserToken);
                
            
        
        em.getTransaction().commit();
     catch (Exception ex) 
        String msg = ex.getLocalizedMessage();
        if (msg == null || msg.length() == 0) 
            Long id = entity.getId();
            if (findOne(id) == null) 
                throw new NonexistentEntityException("The entity with id " + id + " no longer exists.");
            
        
        throw ex;
     finally 
        if (em != null) 
            em.close();
        
    


public void remove(Long key) throws IllegalOrphanException, NonexistentEntityException 
    EntityManager em = null;
    try 
        em = getEntityManager();
        em.getTransaction().begin();
        PortalUser portalUser;
        try 
            portalUser = em.getReference(PortalUser.class, key);
            portalUser.getId();
         catch (EntityNotFoundException enfe) 
            throw new NonexistentEntityException("The portalUser with id " + key + " no longer exists.", enfe);
        
        List<String> illegalOrphanMessages = null;
        Collection<UserToken> userTokensOrphanCheck = portalUser.getUserTokens();
        for (UserToken userTokensOrphanCheckUserToken : userTokensOrphanCheck) 
            if (illegalOrphanMessages == null) 
                illegalOrphanMessages = new ArrayList<String>();
            
            illegalOrphanMessages.add("This PortalUser (" + portalUser + ") cannot be destroyed since the UserToken " + userTokensOrphanCheckUserToken + " in its userTokens field has a non-nullable portalUser field.");
        
        if (illegalOrphanMessages != null) 
            throw new IllegalOrphanException(illegalOrphanMessages);
        
        em.remove(portalUser);
        em.getTransaction().commit();
     finally 
        if (em != null) 
            em.close();
        
    


public List<PortalUser> findAll() 
    EntityManager em = getEntityManager();
    try 
        CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
        cq.select(cq.from(PortalUser.class));
        Query q = em.createQuery(cq);
        return q.getResultList();
     finally 
        em.close();
    


public PortalUser findOne(Long key) 
    EntityManager em = getEntityManager();
    try 
        return em.find(PortalUser.class, key);
     finally 
        em.close();
    


public int count() 
    EntityManager em = getEntityManager();
    try 
        CriteriaQuery cq = em.getCriteriaBuilder().createQuery();
        Root<PortalUser> rt = cq.from(PortalUser.class);
        cq.select(em.getCriteriaBuilder().count(rt));
        Query q = em.createQuery(cq);
        return ((Long) q.getSingleResult()).intValue();
     finally 
        em.close();
    


public PortalUser findPortalUserByUsername(String username)
    EntityManager em = getEntityManager();
    try 
        Query q = em.createQuery("select s from PortalUser s where s.username = '" + username + "'");
        return (PortalUser)q.getSingleResult();
     finally 
        em.close();
    

【参考方案2】：

您需要将PortalUserRepository类标记为@Repository，如下所示：

@Repository
public interface PortalUserRepository extends JpaRepository<PortalUser, Long> 
   //your methods

另外，确保您拥有 @EnableJPARepositories，以便 Spring 容器可以扫描您的存储库接口并为它们提供实现，然后将它们注入您的 SetupDaoV2 bean。

【讨论】：

OP 不使用 Spring，他使用 Guice。除此之外，@Repository 注解在 Spring Data 存储库中是不必要的（如果您阅读注解的 Javadoc，应该很清楚）。

你能指出你所指的API中的文字吗？我找不到..我知道我们可以使用任何刻板印象让 Spring 容器进行扫描

是的，这适用于用作 bean 的类，而不是 Spring Data 的接口。 Javadoc 说“表明一个带注释的类是一个”存储库“”。这些接口已经通过扩展 Spring 数据库接口（如 CrudRepository 或 JpaRepository）进行了标记。这个和@EnableJpaRepositories就够了。

您还可以查看 Spring Data 的示例 (github.com/spring-projects/spring-data-examples)，您会发现没有一个接口上有 @Component 或 @Repository。

最后一件事，您能指出您所指的 Java 文档吗？