java - 无法运行 hibernate (无法加载请求的类)

Question

当我尝试向数据库添加/删除或更改客户时，收到以下错误消息。我尝试更改我的 persistence.xml 但似乎没有办法修复它。

"C:\Program Files\Java\jdk1.8.0_241\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.3.3\lib\idea_rt.jar=52631:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_241\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_241\jre\lib\rt.jar;C:\Users\diona\Documents\Spring boot demo projects\Hibernate with 4HANA\target\classes;C:\Users\diona\.m2\repository\org\hibernate\hibernate-core\5.4.13.Final\hibernate-core-5.4.13.Final.jar;C:\Users\diona\.m2\repository\org\jboss\logging\jboss-logging\3.3.2.Final\jboss-logging-3.3.2.Final.jar;C:\Users\diona\.m2\repository\javax\persistence\javax.persistence-api\2.2\javax.persistence-api-2.2.jar;C:\Users\diona\.m2\repository\org\javassist\javassist\3.24.0-GA\javassist-3.24.0-GA.jar;C:\Users\diona\.m2\repository\net\bytebuddy\byte-buddy\1.10.7\byte-buddy-1.10.7.jar;C:\Users\diona\.m2\repository\antlr\antlr\2.7.7\antlr-2.7.7.jar;C:\Users\diona\.m2\repository\org\jboss\spec\javax\transaction\jboss-transaction-api_1.2_spec\1.1.1.Final\jboss-transaction-api_1.2_spec-1.1.1.Final.jar;C:\Users\diona\.m2\repository\org\jboss\jandex\2.1.1.Final\jandex-2.1.1.Final.jar;C:\Users\diona\.m2\repository\com\fasterxml\classmate\1.5.1\classmate-1.5.1.jar;C:\Users\diona\.m2\repository\javax\activation\javax.activation-api\1.2.0\javax.activation-api-1.2.0.jar;C:\Users\diona\.m2\repository\org\dom4j\dom4j\2.1.1\dom4j-2.1.1.jar;C:\Users\diona\.m2\repository\org\hibernate\common\hibernate-commons-annotations\5.1.0.Final\hibernate-commons-annotations-5.1.0.Final.jar;C:\Users\diona\.m2\repository\javax\xml\bind\jaxb-api\2.3.1\jaxb-api-2.3.1.jar;C:\Users\diona\.m2\repository\org\glassfish\jaxb\jaxb-runtime\2.3.1\jaxb-runtime-2.3.1.jar;C:\Users\diona\.m2\repository\org\glassfish\jaxb\txw2\2.3.1\txw2-2.3.1.jar;C:\Users\diona\.m2\repository\com\sun\istack\istack-commons-runtime\3.0.7\istack-commons-runtime-3.0.7.jar;C:\Users\diona\.m2\repository\org\jvnet\staxex\stax-ex\1.8\stax-ex-1.8.jar;C:\Users\diona\.m2\repository\com\sun\xml\fastinfoset\FastInfoset\1.2.15\FastInfoset-1.2.15.jar;C:\Users\diona\.m2\repository\org\hibernate\hibernate-entitymanager\5.4.13.Final\hibernate-entitymanager-5.4.13.Final.jar" TestSystem
apr 02, 2020 2:44:03 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [name: Hibernate with 4HANA]
apr 02, 2020 2:44:03 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate ORM core version 5.4.13.Final
apr 02, 2020 2:44:03 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
apr 02, 2020 2:44:04 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
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:176)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1214)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1245)
    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 TestSystem.<clinit>(TestSystem.java:13)
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [com.sap.db.jdbc.Driver]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:133)
    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.sap.db.jdbc.Driver
    at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:210)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:130)
    ... 26 more
Exception in thread "main" 
Process finished with exit code 1

我的代码如下所示:

客户.java:

import javax.persistence.*;
import java.io.Serializable;

@Entity
@Table(name="CUSTOMER")
public class Customer implements Serializable {

    @Id
    @Column(name = "custID", unique = true)
    private int id;

    @Column(name = "firstName", nullable = false)
    private String fName;

    @Column(name = "firstName", 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;
    }
}

持久性.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">

    <!-- Define a name used to get an entity manager. Define that you will
    complete transactions with the DB  -->
    <persistence-unit name="Hibernate with 4HANA" transaction-type="RESOURCE_LOCAL">

        <!-- Define the class for Hibernate which implements JPA -->
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <!-- Define the object that should be persisted in the database -->
        <class>Customer</class>
        <properties>
            <!-- Driver for DB database -->
            <property name="javax.persistence.jdbc.driver" value="com.sap.db.jdbc.Driver" />
            <!-- URL for DB -->
            <property name="javax.persistence.jdbc.url" value="xxx" />
            <!-- Username -->
            <property name="javax.persistence.jdbc.user" value="xxx" />
            <!-- Password -->
            <property name="javax.persistence.jdbc.password" value="xxx" />
        </properties>
    </persistence-unit>
</persistence>

测试系统:

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 {
    // Create an EntityManagerFactory when you start the application
    private static final EntityManagerFactory ENTITY_MANAGER_FACTORY = Persistence
            .createEntityManagerFactory("Hibernate with 4HANA");

    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) {
        // The EntityManager class allows operations such as create, read, update, delete
        EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();
        // Used to issue transactions on the EntityManager
        EntityTransaction et = null;

        try {
            // Get transaction and start
            et = em.getTransaction();
            et.begin();

            // Create and set values for new customer
            Customer cust = new Customer();
            cust.setID(id);
            cust.setFName(fname);
            cust.setLName(lname);

            // Save the customer object
            em.persist(cust);
            et.commit();
        } catch (Exception ex) {
            // If there is an exception rollback changes
            if (et != null) {
                et.rollback();
            }
            ex.printStackTrace();
        } finally {
            // Close EntityManager
            em.close();
        }
    }

    public static void getCustomer(int id) {
        EntityManager em = ENTITY_MANAGER_FACTORY.createEntityManager();

        // the lowercase c refers to the object
        // :custID is a parameterized query thats value is set below
        String query = "SELECT c FROM Customer c WHERE c.id = :custID";

        // Issue the query and get a matching Customer
        TypedQuery<Customer> tq = em.createQuery(query, Customer.class);
        tq.setParameter("custID", id);

        Customer cust = null;
        try {
            // Get matching customer object and output
            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();

        // the lowercase c refers to the object
        // :custID is a parameterized query thats value is set below
        String strQuery = "SELECT c FROM Customer c WHERE c.id IS NOT NULL";

        // Issue the query and get a matching Customer
        TypedQuery<Customer> tq = em.createQuery(strQuery, Customer.class);
        List<Customer> custs;
        try {
            // Get matching customer object and output
            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 {
            // Get transaction and start
            et = em.getTransaction();
            et.begin();

            // Find customer and make changes
            cust = em.find(Customer.class, id);
            cust.setFName(fname);

            // Save the customer object
            em.persist(cust);
            et.commit();
        } catch (Exception ex) {
            // If there is an exception rollback changes
            if (et != null) {
                et.rollback();
            }
            ex.printStackTrace();
        } finally {
            // Close EntityManager
            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 there is an exception rollback changes
            if (et != null) {
                et.rollback();
            }
            ex.printStackTrace();
        } finally {
            // Close EntityManager
            em.close();
        }
    }
} 

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<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>org.dlw</groupId>
    <artifactId>Hibernate with 4HANA</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>com.sap.cloud.db.jdbc</groupId>
            <artifactId>ngdbc</artifactId>
            <version>2.4.70</version>
            <type>pom</type>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.4.13.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.4.13.Final</version>
        </dependency>
    </dependencies>

</project>

如果有人能解决这个问题，我们将不胜感激!感谢您的帮助!

Answer 1

TestSystem 不是 JUnit 测试，但您已声明 JDBC 驱动程序测试范围。

删除测试范围，也可能删除类型

   <dependency>
        <groupId>com.sap.cloud.db.jdbc</groupId>
        <artifactId>ngdbc</artifactId>
        <version>2.4.70</version>
    </dependency>

还添加 hibernate 方言:

<property name="hibernate.dialect" value="org.hibernate.dialect.HANAColumnStoreDialect"/>