世代類型標識給出錯誤，表明id（primary key）沒有默認值

Question

我正在嘗試使用身份生成器類並遇到錯誤，因為我正在使用MySQL並使用其他生成器類型，因此代碼可以正常工作，但是當涉及到生成類型“身份”時，它會給我id（電影類）錯誤沒有默認值我嘗試了所有可能找到的解決方案，但是失敗了。 請檢查我的代碼

POJO課

public class Movie {

    private int id;
    private String title;
    private String synopsis;
    private String director;

    public Movie(String title, String synopsis, String direcotr) {
        this.title = title;
        this.synopsis = synopsis;
        this.director = direcotr;

    }

    public Movie() {
    }

    public int getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getSynopsis() {
        return synopsis;
    }

    public void setSynopsis(String synopsis) {
        this.synopsis = synopsis;
    }

    public String getDirector() {
        return director;
    }

    public void setDirector(String director) {
        this.director = director;
    }

}

保存數據

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.exception.GenericJDBCException;

import com.java.commons.HibernateUtil;
import com.java.commons.Movie;

public class SavingData {

    public static void saveData() {
        Session session = null;
        try {
            SessionFactory sessionFactory = HibernateUtil.buldSessionFactory();
            session = sessionFactory.openSession();
            Transaction transaction = session.beginTransaction();
            System.out.println("openSession()");
            System.out.println("session created");
            Movie movie = new Movie("test", "test", "test");
            session.persist(movie);
            transaction.commit();
            session.close();
            System.out.println("data saved with id : " + movie.getId());
        } catch (GenericJDBCException e) {
            System.out.println("error=======> " + e);
            System.out.println("stack trace======>");
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        SavingData.saveData();
    }
}

mapping.xml

<hibernate-mapping>
    <class name="com.java.commons.Movie" table="movie" schema="hibernate">
        <id name="id" type="int" column="id">
            <generator class="identity" />
        </id>
        <property name="title" column="tittle" />
        <property name="synopsis" column="synopsis" />
        <property name="director" column="director" />

    </class>
</hibernate-mapping>

錯誤日志

error=======> org.hibernate.exception.GenericJDBCException: could not execute statement
stack trace======>
org.hibernate.exception.GenericJDBCException: could not execute statement
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:109)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:95)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:207)
    at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:84)
    at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:42)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2792)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3362)
    at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81)
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:597)
    at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:232)
    at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:213)
    at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:256)
    at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:317)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:272)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:178)
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:109)
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189)
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132)
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58)
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:775)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:748)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:753)
    at com.java.saveData.SavingData.saveData(SavingData.java:24)
    at com.java.saveData.SavingData.main(SavingData.java:37)
Caused by: java.sql.SQLException: Field 'id' doesn't have a default value
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2551)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2009)
    at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5094)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1994)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204)
    ... 21 more

根據文檔生成器類型身份可以使用默認值，並且在新數據庫中默認值始終為0，當我執行此操作時會提供錯誤，現在的實際問題是我是否缺少某些內容？ 誰能告訴我錯誤的原因以及如何解決？ 和幫助表示贊賞。 謝謝，謝謝。

Answer 1

在您的堆棧中，hibernate生成的SQL代碼不會生成任何id。 一種解決方案是將MySQL中的id列設置為“ autoincrement”，插入時會生成一個數字。

如果這不起作用，請保持自動遞增並在映射中使用：

<generator class="native"/>

Answer 2

在數據庫中創建一個序列，並按如下所示定義生成器，那么它肯定可以工作：

<generator class="sequence">
        <param name="sequence">sequence_name</param>
</generator>

Answer 3

<hibernate-mapping>
    <class name="com.java.commons.Movie" table="movie" schema="hibernate">
        <id name="id" type="int" column="id">
            <generator class="identity"/>
        </id>
        <property name="title" column="tittle" />
        <property name="synopsis" column="synopsis" />
        <property name="director" column="director" />

    </class>
</hibernate-mapping>

Answer 4

1. 將ID類型從int更改為Integer
2. 確保使用自動模式生成hibernate.hbm2ddl.auto="update"
3. 如果不使用自動模式生成，請確保“ Movie表的id列為AUTO_INCREMENT