Hibernate 启动报错系列
(一)缺少数据库的方言配置:Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ‘hibernate.dialect’ not set
(二)缺少数据库的用户名和密码配置:Caused by: java.sql.SQLException: Access denied for user ‘‘@‘localhost‘ (using password: NO)
一、报错问题
Caused by: java.sql.SQLException: Access denied for user ‘’@‘localhost’ (using password: NO)
二、问题背景
新建Java项目,并添加 Hibernate 框架支持,启动测试(运行默认的Main类中的main()方法),出现报错。
Main.java
import org.hibernate.HibernateException;
import org.hibernate.Metamodel;
import org.hibernate.query.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import javax.persistence.metamodel.EntityType;
import java.util.Map;
public class Main {
private static final SessionFactory ourSessionFactory;
static {
try {
Configuration configuration = new Configuration();
configuration.configure();
ourSessionFactory = configuration.buildSessionFactory();
} catch (Throwable ex) {
throw new ExceptionInInitializerError(ex);
}
}
public static Session getSession() throws HibernateException {
return ourSessionFactory.openSession();
}
public static void main(final String[] args) throws Exception {
final Session session = getSession();
try {
System.out.println("querying all the managed entities...");
final Metamodel metamodel = session.getSessionFactory().getMetamodel();
for (EntityType<?> entityType : metamodel.getEntities()) {
final String entityName = entityType.getName();
final Query query = session.createQuery("from " + entityName);
System.out.println("executing: " + query.getQueryString());
for (Object o : query.list()) {
System.out.println(" " + o);
}
}
} finally {
session.close();
}
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_test</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 配置hibernate的基本信息 -->
<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
<mapping class="com.hibernate.helloworld.TblAccountEntity"/>
<!-- <property name="connection.username"/> -->
<!-- <property name="connection.password"/> -->
<!-- DB schema will be updated if needed -->
<!-- <property name="hibernate.hbm2ddl.auto">update</property> -->
</session-factory>
</hibernate-configuration>
三、原因分析
缺少数据库的用户名和密码配置。
四、解决方案
在 Hibernate 配置文件 hibernate.cfg.xml 中,添加数据库的用户名和密码配置。
<property name="connection.username">root</property>
<property name="connection.password">******</property>
完整示例如下:
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_test</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 配置hibernate的基本信息 -->
<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="connection.username">root</property>
<property name="connection.password">******</property>
<mapping class="com.hibernate.helloworld.TblAccountEntity"/>
<!-- DB schema will be updated if needed -->
<!-- <property name="hibernate.hbm2ddl.auto">update</property> -->
</session-factory>
</hibernate-configuration>