java - 为什么在给mvn clean程序包时出现此错误:找不到表？

Question

我正在建立用户之间的友谊，一个用户可以有任何朋友，有朋友列表，
我正在使用摇摇欲坠来发出请求，但出现错误500，值为空，我不知道为什么

这个错误的控制器，我使用请求后

@CrossOrigin(origins = "http://localhost:4200", maxAge = 3600)
@RestController
@RequestMapping({"/user"})
public class UserController {

    @Autowired
    UserServiceImpl userServiceImpl;
    static Logger log = Logger.getLogger(UserController.class.getName());

    @PostMapping("/create")
    public ResponseEntity<User> createUser(@RequestBody User user) {
        log.info("CREATE");
        return new ResponseEntity<User>(userServiceImpl.createUser(user), HttpStatus.OK);
    }


    @PostMapping("/addFriend")
    public ResponseEntity<User> addFriend(@RequestBody Friendship friendship) {
        log.info("addFriend");
        return new ResponseEntity<User>(userServiceImpl.createLinkWithFriends(friendship), HttpStatus.OK);
    }

    @GetMapping("/getUsers")
    public ResponseEntity<List<User>> getUsers() {
        log.info("getUser");
        return new ResponseEntity<>(userServiceImpl.getUsers(), HttpStatus.OK);
    }

    @GetMapping("/showFriends/{id}")
    public ResponseEntity<List<User>> getUsers(@PathVariable("id")  int id) {
        log.info("showFriends"+id);
        return new ResponseEntity<>(userServiceImpl.getUsers(), HttpStatus.OK);
    }

}

这是我的服务：

@Service
public class UserServiceImpl {
    @Autowired
    UserRepository userRepository;
    @Autowired
    public FriendsRepository friendsRepository;

    public User createUser(User user) {

        if (userRepository.findByEmail(user.getEmail()) == null) {
            return userRepository.save(user);
        }
        return null;
    }

    public User getUser(int index) {
        return null;
    }

    public List<User> getUsers() {
        return userRepository.findAll();
    }



    public User createLinkWithFriends(Friendship friendship) {
        User owner=userRepository.findById(friendship.getOwner().getId());
        User friend=userRepository.findById(friendship.getFriend().getId());
        owner.addFriend(friend);

        friendsRepository.save(friendship);
        return owner;
    }
}

这是存储库用户

@Entity
@Table(name = "User")
public class User implements Serializable {

    private static final long serialVersionUID = -3009157732242241606L;
    @Id
    //@GeneratedValue(strategy = GenerationType.IDENTITY)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @Column(name = "name")
    private String name;

    @Column(name = "password")
    private String password;

    @Column(name = "email")
    private String email;

    @OneToMany(fetch=FetchType.EAGER)
    @JoinTable(
            name = "Friendship",
            joinColumns = @JoinColumn(name = "id"),
            inverseJoinColumns = @JoinColumn(name = "id_friend"))
    private Set<User> friends = new HashSet<>();

    public User() {

    }

    public User(String name, long id, String password, String email) {
        this.email = email;
        this.name = name;
        this.id = id;
        this.password = password;
    }

    public void addFriend(User userFriend){
        this.friends.add(userFriend);
    }

    public Set<User> getFriends() {
        return friends;
    }

    public void setFriends(Set<User> friends) {
        this.friends = friends;
    }

    public String getEmail() {
        return email;
    }

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

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public User(String name) {
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

这就是友谊

@Entity
@Table(name = "Friendship")
public class Friendship implements Serializable {

    private static final long serialVersionUID = -3009157732242241606L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    //@GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id_friend;

    @ManyToOne
    private User owner;

    @ManyToOne
    private User friend;

    public Friendship() {

    }

    public long getId_friend() {
        return id_friend;
    }

    public void setId_friend(long id_friend) {
        this.id_friend = id_friend;
    }

    public User getOwner() {
        return owner;
    }

    public void setOwner(User owner) {
        this.owner = owner;
    }

    public User getFriend() {
        return friend;
    }

    public void setFriend(User friend) {
        this.friend = friend;
    }
}

我收到此错误，为什么我找不到表友谊？这个错误是当我使 mvn clean package

   2019-05-03 23:54:59.925  INFO 20200 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate Core {5.0.12.Final}
2019-05-03 23:54:59.925  INFO 20200 --- [           main] org.hibernate.cfg.Environment            : HHH000206: hibernate.properties not found
2019-05-03 23:54:59.931  INFO 20200 --- [           main] org.hibernate.cfg.Environment            : HHH000021: Bytecode provider name : javassist
2019-05-03 23:54:59.979  INFO 20200 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
2019-05-03 23:55:00.132  INFO 20200 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2019-05-03 23:55:01.094  INFO 20200 --- [           main] org.hibernate.tool.hbm2ddl.SchemaUpdate  : HHH000228: Running hbm2ddl schema update
2019-05-03 23:55:01.132  INFO 20200 --- [           main] rmationExtractorJdbcDatabaseMetaDataImpl : HHH000262: Table not found: friendship
2019-05-03 23:55:01.133  INFO 20200 --- [           main] rmationExtractorJdbcDatabaseMetaDataImpl : HHH000262: Table not found: friendship
2019-05-03 23:55:01.136  WARN 20200 --- [           main] o.s.w.c.s.GenericWebApplicationContext   : Exception encountered during context initialization - cancelling refresh attempt: org.sp
ringframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/Hibern
ateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFac
tory
2019-05-03 23:55:01.152  INFO 20200 --- [           main] utoConfigurationReportLoggingInitializer :

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2019-05-03 23:55:01.184 ERROR 20200 --- [           main] o.s.boot.SpringApplication               : Application startup failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/
HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate Sess
ionFactory

文件application.properties具有以下内容：

spring.h2.console.enabled=true
spring.h2.console.path=/h2_console
spring.datasource.url=jdbc:h2:file:~/test
spring.datasource.username=sa
spring.datasource.password=
spring.datasource.driverClassName=org.h2.Driver
spring.jpa.show-sql=true
spring.jpa.generate-ddl=true
spring.jpa.hibernate.ddl-auto=create

Answer 1

在我看来，插入后为null的连接表（friendship.id_friend）的ID似乎正确。数据库应该在插入过程中将此空值转换为实际的ID，但这不会发生并引起异常。

仔细检查friendship表的设置方式，特别是id_friend列是“自动增量”还是具有类似的触发器。