java - 尝试使用 eclipse 和 hibernate 5 连接到 mysql 数据库

Question

我正在尝试使用 hibernate 5 连接到 mysql，但在控制台上收到此错误。

Exception in thread "main" org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:244)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:208)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
at com.moath.hibernate.HibernateMainTest.main(HibernateMainTest.java:17)
Caused by: org.hibernate.HibernateException: Unable to make JDBC Connection ["jdbc:mysql://localhost:3306/moathdb"] at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:60) at org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:106) at org.hibernate.engine.jdbc.connections.internal.PooledConnections.(PooledConnections.java:40) at org.hibernate.engine.jdbc.connections.internal.PooledConnections.(PooledConnections.java:19) at org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:138) at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:110) at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:74) at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94) at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217) at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189) at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145) at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66) at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88) at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:234)

我已经尝试了与此相关的所有 stackoverflow 问题，但无法解决。

这是实体类:

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;

@Entity(name = "user_details")
public class UserDetails {

@Id
@Column(name = "id")
private int userId;
@Column(name = "user_name")
private String userName;

public int getUserId() {
    return userId;
}

public void setUserId(int userId) {
    this.userId = userId;
}

public String getUserName() {
    return userName;
}

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

}

这是主要方法:

public static void main(String[] args) {

    UserDetails userDetails = new UserDetails();
    userDetails.setUserId(1);
    userDetails.setUserName("First User");

    SessionFactory sessionFactory = new 
    Configuration().configure().buildSessionFactory();
    Session session = sessionFactory.openSession();
    session.beginTransaction();
    session.save(userDetails);
    session.getTransaction().commit();
    session.close();

}

这是 hibernate 配置文件:

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-configuration PUBLIC  
       "-//Hibernate/Hibernate Configuration DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

    <!-- Database connection settings -->
    <property 
name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property 
name="hibernate.connection.url">"jdbc:mysql://localhost:3306/moathdb" 
</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">root</property>

    <!-- SQL dialect -->
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

    <!-- Disable the second-level cache -->
    <property  name="cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>

    <!-- Echo all executed SQL to stdout -->
    <property name="show_sql">true</property>

</session-factory>

我已经检查了数据库用户名和密码，一切都正确，但仍然收到此错误。

Answer 1

如果您使用的是 Mysql 5.x，请使用

org.hibernate.dialect.MySQL5Dialect 

作为方言。

和/或

 <property 
name="hibernate.connection.url">"jdbc:mysql://localhost:3306/moathdb" > 

删除此处的引号。

你的字符串如下所示:

property 
name="hibernate.connection.url">jdbc:mysql://localhost:3306/moathdb>

它会起作用。