无法执行JDBC批处理更新：线程“main”org.hibernate.exception.ConstraintViolationException中的异常：

Question

我刚开始使用hibernate编程，请帮帮我，我在执行下面的文件时遇到了问题。我使用的是MySQL数据库。我的错误是

SLF4J:未能加载类“org.slf4j.impl.StatibloggerBinder”。slf4j:默认为无操作(NOP)记录器实现slf4j:有关更多细节，请参见http://www.slf4j.org/codes.html#staticloggerbinder。Hibernate：插入到UserDetails（用户名）值（？）Hibernate：插入到UserDetails（用户名）值（？）Hibernate：插入到UserDetails（用户名）值（？）Hibernate：插入车辆（vehiName）值（？）Hibernate：插入车辆（vehiName）值（？）Hibernate：插入到userdetails_vehice(UserDetails_userID,vehi_vehiID)值（？,？）Hibernate：插入到userdetails_vehice(UserDetails_userID,vehi_vehiID)值（？,？）Hibernate：插入到userdetails_vehice(UserDetails_userID,vehi_vehiID)值（？,？）

线程“main”org.hibernate.Exception.constraintViolationException：无法在org.hibernate.Exception.jdbcExceptionHelper.convert(sqlstateConverter.convert(sqlstateConverter.java:96)在org.hibernate.Exception.JDBC.exceptionHelper.convert(jdbcExceptionHelper.convert(jdbcExceptionHelper.java:66)在在org.hibernate.event.def.DefaultFlushEventListener.onflush(DefaultFlushEventListener.java:51)，org.hibernate.impl.sessionImpl.flush(SessionImpl.java:1216)，org.hibernate.impl.sessionImpl.managedFlushpdateException：在com.mysql.jdbc.preparedStatement.executeBatchSeryl(preparedStatement.java:1669)在org.hibernate.jdbc.preparedStatement.executeBatch（preparedStatement.java:1085)在org.hibernate.jdbc.batchingBatcher.doExecuteBatch（batchingBatcher.java:70)在org.hibernate.jdbc.abstractBatcher.executeBatch（

@Entity
public class UserDetails {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int userID;
    @OneToMany
    private List<vehicle> vehi = new ArrayList<vehicle>();

    public List<vehicle> getVehi() {
        return vehi;
    }

    public void setVehi(List<vehicle> vehi) {
        this.vehi = vehi;
    }

    public int getUserID() {
        return userID;
    }

    public void setUserID(int userID) {
        this.userID = userID;
    }
    private String userName;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

}

 @Entity
    public class vehicle {

        @Id
        @GeneratedValue
        private int vehiID;

        public int getVehiID() {
            return vehiID;
        }

        public void setVehiID(int vehiID) {
            this.vehiID = vehiID;
        }

        public String getVehiName() {
            return vehiName;
        }

        public void setVehiName(String vehiName) {
            this.vehiName = vehiName;
        }
        private String vehiName;

    }

public class UserTest {

    public static void main(String[] args) {
        vehicle veh1 = new vehicle();
        veh1.setVehiName("car");
        vehicle veh2 = new vehicle();
        veh2.setVehiName("bus");
        UserDetails user1 = new UserDetails();
        UserDetails user2 = new UserDetails();
        user1.setUserName("user2");
        user2.setUserName("user2");
        UserDetails user3 = new UserDetails();
        user3.setUserName("user3");
        user1.getVehi().add(veh1);
        user2.getVehi().add(veh2);
        user3.getVehi().add(veh1);
        SessionFactory sf = new Configuration().configure().buildSessionFactory();
        Session ss = sf.openSession();
        ss.beginTransaction();
        ss.save(user1);
        ss.save(user2);
        ss.save(user3);
        ss.save(veh1);
        ss.save(veh2);
        ss.getTransaction().commit();
        ss.close();
    }

}

Answer 1

错误消息很清楚：有一个唯一的密钥冲突约束：您为两个不同的用户插入了相同的车辆：

user1.getVehi().add(veh1);
//...
user3.getVehi().add(veh1);

这是不正确的，因为用户和车辆之间的关联是一个OneToMany关联。因此，给定的车辆只属于一个用户。如果您希望在用户之间共享一个交通工具，那么您需要一个ManyToMany关联，并且您需要删除userdetails_vehicle.vehi_vehiidon上的唯一约束（如果您使用它来生成模式，Hibernate不会创建它）