无法创建名为“userService”的 bean。通过字段表达的不满足的依赖关系

Question

我在主类中添加了@ComponentScan，@EntityScan仍然是相同的错误，我是新手，几天来就收到了这个错误。请帮忙解决这个问题。

**堆栈跟踪：**

Error creating bean with name 'userService': Unsatisfied dependency expressed through field 'userRepo' : nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository' defined in org.simplilearn.repository.UserRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Invocation of init method failed; nested exception is org.springframework.data.repository.query.QueryCreationException: Could not create query for public abstract java.util.List org.simplilearn.repository.UserRepository.joinUserProductTable(); Reason: Validation failed for query for method public abstract java.util.List org.simplilearn.repository.UserRepository.joinUserProductTable()!; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List org.simplilearn.repository.UserRepository.joinUserProductTable()!

主课

@SpringBootApplication
//@ComponentScan(basePackages = {"org.simplilearn"})
//@EntityScan(basePackages = "org.simplilearn")
public class MedicareApplication {

    public static void main(String[] args) {
        SpringApplication.run(MedicareApplication.class, args);
    }

}

用户服务

@Service
public class UserService {
@Autowired
    private UserRepository userRepo;
    
    // Save the User to the database(POST METHOD)
    public User saveUser(User user)
    {
        return userRepo.save(user);
    }
    
    //Fetch the User from Database(GET METHOD)
    
    public List<User> getUsers(){
        return userRepo.findAll();
    }
    
    public User getUserById(int id) {
        return userRepo.findById(id).orElse(null);
    }
    
    //Delete the User from Database (DELETE METHOD)
    
    public String deleteUserById(int id) {
        userRepo.deleteById(id);
        return "Data" +id+  "Deleted Successfully!";
    }
    
    //Join the User and Product Table
    
    public List<OrderResponse> getUserProductJoinInfos(){
        return userRepo.joinUserProductTable();
    }   
    
}

用户存储库

@Repository
public interface UserRepository extends JpaRepository<User, Integer> {

    @Query("SELECT new org.simplilearn.entity.OrderResponse(u.UserId,u.name,u.email, u.mobile, u.address, p.medicinename, p.seller"+ ", p.price, p.description, p.quantity, p.orderDateTime) FROM User u JOIN u.products p")

    public List<OrderResponse> joinUserProductTable();
}

用户实体

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int UserId;
    private int age;
    private String name;
    private String email;
    private String gender;
    private String address;
    private String mobile;

    @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)

    @JoinTable(name = "USER_PRODUCT_TABLE", joinColumns = { @JoinColumn(name = "user_id", referencedColumnName = "UserId") }, inverseJoinColumns = { @JoinColumn(name = "product_id", referencedColumnName = "pid") })

    private List<Product> products;

    public User() {
    }

    public User( int age, String name, String email, String gender, String address, String mobile, List<Product> products) {
        super();
        
        this.age = age;
        this.name = name;
        this.email = email;
        this.gender = gender;
        this.address = address;
        this.mobile = mobile;
        this.products = products;
    }

    public int getUserId() {
        return UserId;
    }

    public void setUserId(int userId) {
        UserId = userId;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getMobile() {
        return mobile;
    }

    public void setMobile(String mobile) {
        this.mobile = mobile;
    }

    public List<Product> getProducts() {
        return products;
    }

    public void setProducts(List<Product> products) {
        this.products = products;
    }

    @Override
    public String toString() {
        return "User [UserId=" + UserId + ", age=" + age + ", name=" + name + ", email=" + email + ", gender=" + gender
                + ", address=" + address + ", mobile=" + mobile + ", products=" + products + "]";
    }

}

我在主类中添加了@ComponentScan，@EntityScan仍然是相同的错误，我是新手，几天来就收到了这个错误。请帮忙解决这个问题。

Answer 1

@SpringBootApplication 已经有 @ComponentScan 了。您可以将鼠标悬停在注释上并查看列表。它扫描 Java 下的文件夹 com.example.myApplication 文件夹。如果您的组件不在这里，则无法扫描。

如果有任何拼写错误，我还会检查查询中的列名称。