Java 使用Spring、JPA和Hibernate的通用DAO设置_Java_Spring_Hibernate

Java 使用Spring、JPA和Hibernate的通用DAO设置

java spring hibernate

Java 使用Spring、JPA和Hibernate的通用DAO设置,java,spring,hibernate,Java,Spring,Hibernate,我试图编写一个通用代码，在任何实体上实现一些最常见的操作。我已经使用SpringInitializer使用Gradle、SpringBoot2.1.0Snapshot、JPA和Hibernate生成了产品的基础。我使用MySQL Workbench创建了模式和表，并使用它为我的项目生成实体。因此，谈到实际问题，我尝试创建一个通用DAO，其中一些常见操作（如findbyid、edit、delete、create、update、getall）将被实现，然后将其扩展到其他DAO类，以提高可重用性并加快

我试图编写一个通用代码，在任何实体上实现一些最常见的操作。我已经使用SpringInitializer使用Gradle、SpringBoot2.1.0Snapshot、JPA和Hibernate生成了产品的基础。我使用MySQL Workbench创建了模式和表，并使用它为我的项目生成实体。因此，谈到实际问题，我尝试创建一个通用DAO，其中一些常见操作（如findbyid、edit、delete、create、update、getall）将被实现，然后将其扩展到其他DAO类，以提高可重用性并加快工作速度。这是我到目前为止的代码：

UserController.java：

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping(value = "/getUser", method = RequestMethod.GET)
    @ResponseBody
    public UserEntity getUser() throws Exception {
        userService.getUser();
    }
}

public interface UserService {
    UsersEntity getUser();
}

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDAO userDAO;

    @Transactional
    public UsersEntity getUser() {
        return userDAO.find(Long.valueOf("123"));
    }
}

public interface UserDAO extends GenericRepositoryInterface<UsersEntity> {
}

@Repository
public abstract class UserDAOImpl implements UserDAO {
}

public interface GenericRepositoryInterface<T> {
    T save(T emp);
    Boolean delete(T emp);
    T edit(T emp);
    T find(Long empId);
}

@Repository
public class GenericRepositoryImplementation<T> implements GenericRepositoryInterface<T> {

    protected EntityManager entityManager;
    private T type;

    public GenericRepositoryImplementation(T type) {
        // TODO Auto-generated constructor stub
        this.type = type;
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }

    @PersistenceContext
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T emp) {
        // TODO Auto-generated method stub
        entityManager.persist(emp);
        entityManager.flush();
        return emp;
    }

    @Override
    public Boolean delete(T emp) {
        // TODO Auto-generated method stub
        try {
            entityManager.remove(emp);
        } catch (Exception ex) {
            return false;
        }
        return true;
    }

    @Override
    public T edit(T emp) {
        // TODO Auto-generated method stub
        try{
            return entityManager.merge(emp);
        } catch(Exception ex) {
            return null;
        }
    }

    @Override
    public T find(Long empId) {
        // TODO Auto-generated method stub
        return (T) entityManager.find(type.getClass(), empId);
    }
}

UserService.java：

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping(value = "/getUser", method = RequestMethod.GET)
    @ResponseBody
    public UserEntity getUser() throws Exception {
        userService.getUser();
    }
}

public interface UserService {
    UsersEntity getUser();
}

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDAO userDAO;

    @Transactional
    public UsersEntity getUser() {
        return userDAO.find(Long.valueOf("123"));
    }
}

public interface UserDAO extends GenericRepositoryInterface<UsersEntity> {
}

@Repository
public abstract class UserDAOImpl implements UserDAO {
}

public interface GenericRepositoryInterface<T> {
    T save(T emp);
    Boolean delete(T emp);
    T edit(T emp);
    T find(Long empId);
}

@Repository
public class GenericRepositoryImplementation<T> implements GenericRepositoryInterface<T> {

    protected EntityManager entityManager;
    private T type;

    public GenericRepositoryImplementation(T type) {
        // TODO Auto-generated constructor stub
        this.type = type;
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }

    @PersistenceContext
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T emp) {
        // TODO Auto-generated method stub
        entityManager.persist(emp);
        entityManager.flush();
        return emp;
    }

    @Override
    public Boolean delete(T emp) {
        // TODO Auto-generated method stub
        try {
            entityManager.remove(emp);
        } catch (Exception ex) {
            return false;
        }
        return true;
    }

    @Override
    public T edit(T emp) {
        // TODO Auto-generated method stub
        try{
            return entityManager.merge(emp);
        } catch(Exception ex) {
            return null;
        }
    }

    @Override
    public T find(Long empId) {
        // TODO Auto-generated method stub
        return (T) entityManager.find(type.getClass(), empId);
    }
}

UserServiceImpl.java：

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping(value = "/getUser", method = RequestMethod.GET)
    @ResponseBody
    public UserEntity getUser() throws Exception {
        userService.getUser();
    }
}

public interface UserService {
    UsersEntity getUser();
}

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDAO userDAO;

    @Transactional
    public UsersEntity getUser() {
        return userDAO.find(Long.valueOf("123"));
    }
}

public interface UserDAO extends GenericRepositoryInterface<UsersEntity> {
}

@Repository
public abstract class UserDAOImpl implements UserDAO {
}

public interface GenericRepositoryInterface<T> {
    T save(T emp);
    Boolean delete(T emp);
    T edit(T emp);
    T find(Long empId);
}

@Repository
public class GenericRepositoryImplementation<T> implements GenericRepositoryInterface<T> {

    protected EntityManager entityManager;
    private T type;

    public GenericRepositoryImplementation(T type) {
        // TODO Auto-generated constructor stub
        this.type = type;
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }

    @PersistenceContext
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T emp) {
        // TODO Auto-generated method stub
        entityManager.persist(emp);
        entityManager.flush();
        return emp;
    }

    @Override
    public Boolean delete(T emp) {
        // TODO Auto-generated method stub
        try {
            entityManager.remove(emp);
        } catch (Exception ex) {
            return false;
        }
        return true;
    }

    @Override
    public T edit(T emp) {
        // TODO Auto-generated method stub
        try{
            return entityManager.merge(emp);
        } catch(Exception ex) {
            return null;
        }
    }

    @Override
    public T find(Long empId) {
        // TODO Auto-generated method stub
        return (T) entityManager.find(type.getClass(), empId);
    }
}

UserDAO.java：

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping(value = "/getUser", method = RequestMethod.GET)
    @ResponseBody
    public UserEntity getUser() throws Exception {
        userService.getUser();
    }
}

public interface UserService {
    UsersEntity getUser();
}

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDAO userDAO;

    @Transactional
    public UsersEntity getUser() {
        return userDAO.find(Long.valueOf("123"));
    }
}

public interface UserDAO extends GenericRepositoryInterface<UsersEntity> {
}

@Repository
public abstract class UserDAOImpl implements UserDAO {
}

public interface GenericRepositoryInterface<T> {
    T save(T emp);
    Boolean delete(T emp);
    T edit(T emp);
    T find(Long empId);
}

@Repository
public class GenericRepositoryImplementation<T> implements GenericRepositoryInterface<T> {

    protected EntityManager entityManager;
    private T type;

    public GenericRepositoryImplementation(T type) {
        // TODO Auto-generated constructor stub
        this.type = type;
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }

    @PersistenceContext
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T emp) {
        // TODO Auto-generated method stub
        entityManager.persist(emp);
        entityManager.flush();
        return emp;
    }

    @Override
    public Boolean delete(T emp) {
        // TODO Auto-generated method stub
        try {
            entityManager.remove(emp);
        } catch (Exception ex) {
            return false;
        }
        return true;
    }

    @Override
    public T edit(T emp) {
        // TODO Auto-generated method stub
        try{
            return entityManager.merge(emp);
        } catch(Exception ex) {
            return null;
        }
    }

    @Override
    public T find(Long empId) {
        // TODO Auto-generated method stub
        return (T) entityManager.find(type.getClass(), empId);
    }
}

GenericRepositoryInterface.java：

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @RequestMapping(value = "/getUser", method = RequestMethod.GET)
    @ResponseBody
    public UserEntity getUser() throws Exception {
        userService.getUser();
    }
}

public interface UserService {
    UsersEntity getUser();
}

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDAO userDAO;

    @Transactional
    public UsersEntity getUser() {
        return userDAO.find(Long.valueOf("123"));
    }
}

public interface UserDAO extends GenericRepositoryInterface<UsersEntity> {
}

@Repository
public abstract class UserDAOImpl implements UserDAO {
}

public interface GenericRepositoryInterface<T> {
    T save(T emp);
    Boolean delete(T emp);
    T edit(T emp);
    T find(Long empId);
}

@Repository
public class GenericRepositoryImplementation<T> implements GenericRepositoryInterface<T> {

    protected EntityManager entityManager;
    private T type;

    public GenericRepositoryImplementation(T type) {
        // TODO Auto-generated constructor stub
        this.type = type;
    }

    public EntityManager getEntityManager() {
        return entityManager;
    }

    @PersistenceContext
    public void setEntityManager(EntityManager entityManager) {
        this.entityManager = entityManager;
    }

    @Override
    public T save(T emp) {
        // TODO Auto-generated method stub
        entityManager.persist(emp);
        entityManager.flush();
        return emp;
    }

    @Override
    public Boolean delete(T emp) {
        // TODO Auto-generated method stub
        try {
            entityManager.remove(emp);
        } catch (Exception ex) {
            return false;
        }
        return true;
    }

    @Override
    public T edit(T emp) {
        // TODO Auto-generated method stub
        try{
            return entityManager.merge(emp);
        } catch(Exception ex) {
            return null;
        }
    }

    @Override
    public T find(Long empId) {
        // TODO Auto-generated method stub
        return (T) entityManager.find(type.getClass(), empId);
    }
}

我不知道为什么，但在提到的位置存在一个UserDAO类，它无法识别它。我是否遗漏了任何注释或任何内容？

未找到

UserDAO

的实现

您希望扩展通用DAO实现：

@Repository
public class UserDAOImpl extends GenericRepositoryImplementation< UsersEntity> implements UserDAO {
     public UserDaoImpl() {
          super(UsersEntity.class);
     }
}

我认为问题在于你的UserDAOImpl。

在这里，您试图注入一个抽象类的依赖项。为userDao提供具体的类，然后将其注入控制器/服务

谢谢！我完全忽略了一个问题，即我使用的是一个抽象类，扩展没有正确完成。