Question

无论我做什么，JPA都不适合我。我完全按照udemy上的课程进行操作，尝试导入实际项目（更改mysql用户/密码），并尝试了YouTube上的其他教程。什么都没有。

以下是该课程的导入源。 Pom和持久性看上去很像Internet上的大多数。 Main App本身在课程的后面，因为我找不到旧的来源。但是，即使最基本的代码也不起作用。

我的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.udemy</groupId>
<artifactId>FirstJPAProject</artifactId>
<version>0.0.1-SNAPSHOT</version>
<build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>
<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>6.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate.javax.persistence</groupId>
        <artifactId>hibernate-jpa-2.1-api</artifactId>
        <version>1.0.0.Final</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.3.11.Final</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>4.3.11.Final</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>4.3.0.Final</version>
    </dependency>
</dependencies>

我的persistence.xml：

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="1.0"
    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_1_0.xsd">
    <persistence-unit name="personal_jpa" transaction-type="RESOURCE_LOCAL">  
        <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <properties>
            <property name="hibernate.archive.autodetection" value="class" />

            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
            <property name="hibernate.connection.driver_class" value="com.mysql.cj.jdbc.Driver" />
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost/udemy?serverTimezone=UTC" />
            <property name="hibernate.connection.user" value="root" />
            <property name="hibernate.connection.password" value="Password123" />
            <property name="hibernate.hbm2ddl.auto" value="update"/>

            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="use_sql_comments" value="true" />

        </properties>
    </persistence-unit>
</persistence>

我的主班：

package com.udemy.jpa;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import javax.persistence.TypedQuery;

public class App {

    public static void main(String[] args) {

        EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("personal_jpa");

        EntityManager entityManager = entityManagerFactory.createEntityManager();
        entityManager.getTransaction().begin();

        TypedQuery<Person> query = entityManager.createNamedQuery("person.getPersonByName", Person.class);
        query.setParameter("name", "Adam");

        List<Person> people = query.getResultList();

        for (Person p : people) {
            System.out.println(p);
        }

        entityManager.close();
        entityManagerFactory.close();

    }
}

而且我一直都在遇到这个（或类似的）错误：

Nov 25, 2018 7:40:34 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
Nov 25, 2018 7:40:34 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
Nov 25, 2018 7:40:34 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
Nov 25, 2018 7:40:34 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [
    name: personal_jpa
    ...]
Nov 25, 2018 7:40:34 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.3.11.Final}
Nov 25, 2018 7:40:34 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
Nov 25, 2018 7:40:34 PM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
Nov 25, 2018 7:40:35 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.5.Final}
Nov 25, 2018 7:40:35 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH000402: Using Hibernate built-in connection pool (not for production use!)
Nov 25, 2018 7:40:35 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000401: using driver [com.mysql.cj.jdbc.Driver] at URL [jdbc:mysql://localhost/udemy?serverTimezone=UTC]
Nov 25, 2018 7:40:35 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000046: Connection properties: {user=root, password=****}
Nov 25, 2018 7:40:35 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH000006: Autocommit mode: false
Nov 25, 2018 7:40:35 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
Sun Nov 25 19:40:35 CET 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Exception in thread "main" javax.persistence.PersistenceException: Unable to build entity manager factory
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:83)
    at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:54)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39)
    at com.udemy.inheritance.App.main(App.java:10)
Caused by: org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:122)
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:140)
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:58)
    at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:75)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:106)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:111)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:234)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:206)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.buildJdbcConnectionAccess(JdbcServicesImpl.java:260)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:94)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:111)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:234)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:206)
    at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1887)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1845)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:857)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:425)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:849)
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:75)
    ... 4 more
Caused by: java.sql.SQLException: Unable to load authentication plugin 'caching_sha2_password'.
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:695)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:663)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:653)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:638)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:606)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:624)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:620)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:77)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1683)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:656)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:349)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:221)
    at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:55)
    ... 21 more
Caused by: com.mysql.cj.core.exceptions.WrongArgumentException: Unable to load authentication plugin 'caching_sha2_password'.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:54)
    at com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:73)
    at com.mysql.cj.mysqla.authentication.MysqlaAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(MysqlaAuthenticationProvider.java:550)
    at com.mysql.cj.mysqla.authentication.MysqlaAuthenticationProvider.connect(MysqlaAuthenticationProvider.java:196)
    at com.mysql.cj.mysqla.io.MysqlaProtocol.connect(MysqlaProtocol.java:1712)
    at com.mysql.cj.mysqla.MysqlaSession.connect(MysqlaSession.java:149)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:1803)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1673)
    ... 25 more

Answer 1

色拉：好吧，问题的根源似乎来自MySQL 连接器：“ WrongArgumentException：无法加载身份验证插件“ caching_sha2_password””。确保已配置所有内容正确，包括MySQL端。您似乎确实在使用较旧版本的mysql-connector-java。如果再尝试一次会怎样？最新版本？

现在可以使用。不得不尝试其他版本。

JPA问题：无法建立实体管理器工厂

1 个答案: