SpringBoot整合JPA的动态查询怎么做

来源：佚名编辑：佚名

2024-06-14 14:03:34

在SpringBoot中整合JPA进行动态查询，主要涉及到使用Criteria API或者Querydsl来构建动态查询条件。下面是一个简单的示例来演示如何实现动态查询：

创建一个实体类和对应的Repository接口:

@Entity
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    private String username;
    
    private String email;
    
    // getters and setters
}

public interface UserRepository extends JpaRepository<User, Long> {
    
}

创建一个Service类来实现动态查询:

@Service
public class UserService {
    
    @Autowired
    private UserRepository userRepository;
    
    public List<User> searchUsers(String username, String email) {
        CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
        CriteriaQuery<User> query = criteriaBuilder.createQuery(User.class);
        Root<User> root = query.from(User.class);
        
        List<Predicate> predicates = new ArrayList<>();
        
        if (username != null) {
            predicates.add(criteriaBuilder.like(root.get("username"), "%" + username + "%"));
        }
        
        if (email != null) {
            predicates.add(criteriaBuilder.equal(root.get("email"), email));
        }
        
        query.where(predicates.toArray(new Predicate[predicates.size()]));
        
        return entityManager.createQuery(query).getResultList();
    }
}