java - 线程中的异常 "main"org.hibernate.service.spi.ServiceException : Unable to create requested service Hibernate Error

Question

尝试使用 Hibernate 在数据库中添加用户时遇到下一个错误:

WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
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:271)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
    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:242)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
    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:691)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
    at Main.main(Main.java:16)
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [com.mysql.jdbc.Driver]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:348)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible(DriverManagerConnectionProviderImpl.java:160)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator(DriverManagerConnectionProviderImpl.java:116)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:100)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
    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:259)
    ... 14 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:336)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:345)
    ... 26 more

这是我的用户类:

@Entity
public class User {

@Id 
private int id;
private String username;
private String password;
private String address;
private String email;
private String phone;
private int year;
private String type;


public User(int id, String username, String password, String address,String email, String phone, int year, String type)
    {
        this.id=id;
        this.username=username;
        this.password=password;
        this.address=address;
        this.email=email;
        this.phone=phone;
        this.year=year;
        this.type=type;
    }


public User() {
    // TODO Auto-generated constructor stub
}


public int getId() {
    return id;
}


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


public String getUsername() {
    return username;
}


public void setUsername(String username) {
    this.username = username;
}


public String getPassword() {
    return password;
}


public void setPassword(String password) {
    this.password = password;
}
//here are more getters and setters..

然后是hibernate配置文件:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory>
        <property name="hibernate.dialect">
            org.hibernate.dialect.MySQLDialect
        </property>
        <property name="hibernate.connection.driver_class">
            com.mysql.jdbc.Driver
        </property>

        <!-- Assume test is the database name -->
        <property name="hibernate.connection.url">
            jdbc:mysql://localhost:3306/licenta
        </property>
        <property name="hibernate.connection.username">
            root
        </property>
        <property name="hibernate.connection.password">root</property>
        <mapping resource="user.hbm.xml" />

    </session-factory>
</hibernate-configuration>

主要方法:

public static void main(String[] args)
    {

        User u=new User();
        u.setId(1);
        u.setUsername("lalalla");
        SessionFactory sessionFactory = new Configuration().configure("hibernate.cfg.xml").buildSessionFactory();
        Session session = sessionFactory.openSession();
        session.beginTransaction();
        session.save(u);
        session.getTransaction().commit();

        session.close();

    }

这里是我安装的 hibernate 版本中的所有 JAR，继续 JAR

我找不到解决这个问题的方法。你们能帮我吗？

谢谢!

Answer 1

这个错误

Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver

意味着您的类路径中没有 MySQL 的 JDBC 驱动程序。我检查了你的 jar ，但没有找到。因此，您应该将此 jar 添加到类路径中。

您可以在那里找到连接器 https://dev.mysql.com/downloads/connector/j/

或者如果你使用maven:

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.6</version>
</dependency>