Hibernate error: java.lang.ClassNotFoundException: Could not load requested class
Hibernate error: java.lang.ClassNotFoundException: Could not load requested class
我是 Hibernate 的新手，在执行第一个程序时遇到了一些问题：
java.lang.ClassNotFoundException：无法加载请求 class：com.mysql.jdbc.Driver。我正在学习有关 Hibernate 的教程，所做的一切都是一样的（甚至复制了所有内容并尝试 运行）。我一直在整个互联网上寻找答案，但其中 none 帮助了我。
persistence.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="myPassword!" />
</properties>
</persistence-unit>
</persistence>
pom.xml:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.newthinktank</groupId>
<artifactId>JEETut3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>JEETut3</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.15</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
*顾客：*
package com.newthinktank.JEETut3;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "customer")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private int id;
@Column(name = "firstName", nullable = false)
private String fName;
@Column(name = "lastName", nullable = false)
private String lName;
public int getID() {
return id;
}
public void setID(int id) {
this.id = id;
}
public String getFName() {
return fName;
}
public void setFName(String fName) {
this.fName = fName;
}
public String getLName() {
return lName;
}
public void setLName(String lName) {
this.lName = lName;
}
}
测试系统：
package com.newthinktank.JEETut3;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.NoResultException;
import javax.persistence.Persistence;
import javax.persistence.TypedQuery;
public class TestSystem {
private static final EntityManagerFactory ENTITY_MANAGER_FACTORY = Persistence
.createEntityManagerFactory("JEETut3");
public static void main(String[] args) {
addCustomer(1, "Sue", "Smith");
addCustomer(2, "Sam", "Smith");
addCustomer(3, "Sid", "Smith");
addCustomer(4, "Sally", "Smith");
getCustomer(1);
getCustomers();
changeFName(4, "Mark");
deleteCustomer(3);
ENTITY_MANAGER_FACTORY.close();
}
public static void addCustomer(int id, String fname, String lname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
try {
et = em.getTransaction();
et.begin();
Customer cust = new Customer();
cust.setID(id);
cust.setFName(fname);
cust.setLName(lname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String query = "SELECT c FROM Customer c WHERE c.id = :custID";
TypedQuery<Customer> tq = em.createQuery(query, Customer.class);
tq.setParameter("custID", id);
Customer cust = null;
try {
cust = tq.getSingleResult();
System.out.println(cust.getFName() + " " + cust.getLName());
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomers() {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String strQuery = "SELECT c FROM Customer c WHERE c.id IS NOT NULL";
TypedQuery<Customer> tq = em.createQuery(strQuery, Customer.class);
List<Customer> custs;
try {
custs = tq.getResultList();
custs.forEach(cust -> System.out.println(cust.getFName() + " " + cust.getLName()));
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void changeFName(int id, String fname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
cust.setFName(fname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void deleteCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
em.remove(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
}
错误：
lip 24, 2020 1:42:49 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: JEETut3]
lip 24, 2020 1:42:49 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.4.3.Final}
lip 24, 2020 1:42:49 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
lip 24, 2020 1:42:49 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: 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:275)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:175)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:900)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:931)
at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
at com.newthinktank.JEETut3.TestSystem.<clinit>(TestSystem.java:15)
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:136)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible(DriverManagerConnectionProviderImpl.java:149)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator(DriverManagerConnectionProviderImpl.java:105)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:89)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:73)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:107)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:246)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
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:101)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
... 14 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver
at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:416)
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:133)
... 26 more
有人知道如何解决问题吗？
我已经测试了你的代码，问题出在 mysql maven 依赖项中你需要删除提供的范围，因为你说它会在 运行ning 时提供，但事实并非如此.
这些是我为实现它所做的更改 运行。
删除提供的范围 mysql maven 依赖项
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.15</version>
</dependency>
更改 persistence.xml 中的 jdbc 驱动程序，因为您使用的驱动程序已弃用
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
您还缺少 persistence.xml 代码的必填部分
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
我还在persistence.xml
中添加了数据库的方言
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
如果您希望在每次执行时自动创建表，您可以添加
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
总结下来就是我用的持久化
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="myPassword!"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
</properties>
</persistence-unit>
这是您将在数据库中获得的结果
希望这能帮助您解决问题
我是 Hibernate 的新手，在执行第一个程序时遇到了一些问题： java.lang.ClassNotFoundException：无法加载请求 class：com.mysql.jdbc.Driver。我正在学习有关 Hibernate 的教程，所做的一切都是一样的（甚至复制了所有内容并尝试 运行）。我一直在整个互联网上寻找答案，但其中 none 帮助了我。 persistence.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="myPassword!" />
</properties>
</persistence-unit>
</persistence>
pom.xml:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.newthinktank</groupId>
<artifactId>JEETut3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>JEETut3</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.4.1.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.15</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
package com.newthinktank.JEETut3;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "customer")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private int id;
@Column(name = "firstName", nullable = false)
private String fName;
@Column(name = "lastName", nullable = false)
private String lName;
public int getID() {
return id;
}
public void setID(int id) {
this.id = id;
}
public String getFName() {
return fName;
}
public void setFName(String fName) {
this.fName = fName;
}
public String getLName() {
return lName;
}
public void setLName(String lName) {
this.lName = lName;
}
}
测试系统：
package com.newthinktank.JEETut3;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.NoResultException;
import javax.persistence.Persistence;
import javax.persistence.TypedQuery;
public class TestSystem {
private static final EntityManagerFactory ENTITY_MANAGER_FACTORY = Persistence
.createEntityManagerFactory("JEETut3");
public static void main(String[] args) {
addCustomer(1, "Sue", "Smith");
addCustomer(2, "Sam", "Smith");
addCustomer(3, "Sid", "Smith");
addCustomer(4, "Sally", "Smith");
getCustomer(1);
getCustomers();
changeFName(4, "Mark");
deleteCustomer(3);
ENTITY_MANAGER_FACTORY.close();
}
public static void addCustomer(int id, String fname, String lname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
try {
et = em.getTransaction();
et.begin();
Customer cust = new Customer();
cust.setID(id);
cust.setFName(fname);
cust.setLName(lname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String query = "SELECT c FROM Customer c WHERE c.id = :custID";
TypedQuery<Customer> tq = em.createQuery(query, Customer.class);
tq.setParameter("custID", id);
Customer cust = null;
try {
cust = tq.getSingleResult();
System.out.println(cust.getFName() + " " + cust.getLName());
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void getCustomers() {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
String strQuery = "SELECT c FROM Customer c WHERE c.id IS NOT NULL";
TypedQuery<Customer> tq = em.createQuery(strQuery, Customer.class);
List<Customer> custs;
try {
custs = tq.getResultList();
custs.forEach(cust -> System.out.println(cust.getFName() + " " + cust.getLName()));
} catch (NoResultException ex) {
ex.printStackTrace();
} finally {
em.close();
}
}
public static void changeFName(int id, String fname) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
cust.setFName(fname);
em.persist(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
public static void deleteCustomer(int id) {
EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
EntityTransaction et = null;
Customer cust = null;
try {
et = em.getTransaction();
et.begin();
cust = em.find(Customer.class, id);
em.remove(cust);
et.commit();
} catch (Exception ex) {
if (et != null) {
et.rollback();
}
ex.printStackTrace();
} finally {
em.close();
}
}
}
错误：
lip 24, 2020 1:42:49 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: JEETut3]
lip 24, 2020 1:42:49 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.4.3.Final}
lip 24, 2020 1:42:49 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
lip 24, 2020 1:42:49 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: 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:275)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:175)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:900)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:931)
at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
at com.newthinktank.JEETut3.TestSystem.<clinit>(TestSystem.java:15)
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:136)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible(DriverManagerConnectionProviderImpl.java:149)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator(DriverManagerConnectionProviderImpl.java:105)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:89)
at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:73)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:107)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:246)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
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:101)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
... 14 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.mysql.jdbc.Driver
at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:416)
at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:133)
... 26 more
有人知道如何解决问题吗？
我已经测试了你的代码，问题出在 mysql maven 依赖项中你需要删除提供的范围，因为你说它会在 运行ning 时提供，但事实并非如此.
这些是我为实现它所做的更改 运行。
删除提供的范围 mysql maven 依赖项
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.15</version> </dependency>
更改 persistence.xml 中的 jdbc 驱动程序，因为您使用的驱动程序已弃用
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
您还缺少 persistence.xml 代码的必填部分
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
我还在persistence.xml
中添加了数据库的方言<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
如果您希望在每次执行时自动创建表，您可以添加
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
总结下来就是我用的持久化
<persistence-unit name="JEETut3" transaction-type="RESOURCE_LOCAL">
<class>com.newthinktank.JEETut3.Customer</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test4"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="myPassword!"/>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
<property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/>
</properties>
</persistence-unit>
这是您将在数据库中获得的结果
希望这能帮助您解决问题