org.hibernate.exception.sqlgrammarexception：无法提取ResultSet

Question

我已经将支持JAR和jdbc驱动程序添加到我的项目中，但我仍然得到了低于例外情况

getting找不到resultset异常错误执行load命令：getting sqlgrammerexception

我的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.password">1234</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <mapping class="com.util.Product"/>
    </session-factory>
</hibernate-configuration
entity class
@Entity
@Table(name="productdetails")
public class Product implements Serializable {

    @Id
    @Column(name="product-id")
    private int id;
    @Column(name="product-name")
    private String name;
    @Column(name="product-description")
    private String description;
    @Column(name="product-price")
    private float price;
    public Product() {
        super();
    }

    public Product(int id, String name, String description, float price) {
        super();
        this.id = id;
        this.name = name;
        this.description = description;
        this.price = price;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }

}

public class Executingclass {
    public static void  main(String args[]) {
        SessionFactory  sessionFactory=Hibernateutil.getSessionFactory();
        Session session=sessionFactory.openSession();
        Product product=(Product)session.get(Product.class, 1);
        System.out.println(product.getId());
        System.out.println(product.getName());
        System.out.println(product.getDescription());
        System.out.println(product.getPrice());


    }

}

public class Hibernateutil {
    static SessionFactory sessionFactory=null;
    static{
        Configuration configuration=new Configuration();
        configuration.configure();

        ServiceRegistry serviceRegistry=new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
        sessionFactory=configuration.buildSessionFactory(serviceRegistry);
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

INFO: HHH000327: Error performing load command : org.hibernate.exception.SQLGrammarException: could not extract ResultSet
Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not extract ResultSet
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:80)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:91)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:449)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:202)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:137)
    at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeLoad(AbstractLoadPlanBasedLoader.java:102)
    at org.hibernate.loader.entity.plan.AbstractLoadPlanBasedEntityLoader.load(AbstractLoadPlanBasedEntityLoader.java:186)
    at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:4126)
    at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:503)
    at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:468)
    at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:213)
    at org.hibernate.event.internal.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:275)
    at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:151)
    at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1106)
    at org.hibernate.internal.SessionImpl.access$2000(SessionImpl.java:176)
    at org.hibernate.internal.SessionImpl$IdentifierLoadAccessImpl.load(SessionImpl.java:2587)
    at org.hibernate.internal.SessionImpl.get(SessionImpl.java:991)
    at com.util.Executingclass.main(Executingclass.java:10)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'product0_.product' in 'field list'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
    at com.mysql.jdbc.Util.getInstance(Util.java:387)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:941)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2470)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2617)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2550)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1962)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:82)
    ... 16 more

Answer 1

在stacktrace中,有一条线指向问题：

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'product0_.product' in 'field list'

如果您看到unknown column，我首先想到的是类中字段的映射存在一些错误。

@Id
@Column(name="product-id")
private int id;
@Column(name="product-name")
private String name;
@Column(name="product-description")
private String description;
@Column(name="product-price")
private float price;

当你看到这个和我上面提到的stacktrace中的输出时，你会想，嗯，没有product0_.product列名，最接近的只是product，后面跟一个连字符，也许就是这个连字符给你带来了一些麻烦。

在搜索了一下之后，我从另一个问题中找到了这个答案，这个问题指出使用连字符是可能的，但是它有一个特殊的要求，也许hibernate没有正确地处理这个问题。

因此，总而言之，尝试在模式、数据库和@entity中不使用连字符。