【发布时间】：2024-04-26 04:30:01
【问题描述】：
您好，我是 java 新手。我用 jpa 做了一个安静的应用程序，但是 JPA 有问题。我无法创建 EntityManager，也无法理解错误：
No Persistence provider for EntityManager named my-app: Provider named org.hibernate.ejb.HibernatePersistence threw unexpected exception at create EntityManagerFactory
因为我不使用 org.hibernate.ejb.HibernatePersistence，而是使用我的 persistence.xml 文件中指定的 org.hibernate.jpa.HibernatePersistenceProvider：
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
version="2.1">
<persistence-unit name="my-app" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://http://localhost:3306/tink" />
<property name="javax.persistence.jdbc.user" value="*****" />
<property name="javax.persistence.jdbc.password" value="*****" />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
<property name="hibernate.hbm2ddl.auto" value="validate" />
<!-- Configuring Connection Pool -->
<property name="hibernate.c3p0.min_size" value="5" />
<property name="hibernate.c3p0.max_size" value="20" />
<property name="hibernate.c3p0.timeout" value="500" />
<property name="hibernate.c3p0.max_statements" value="50" />
<property name="hibernate.c3p0.idle_test_period" value="2000" />
</properties>
</persistence-unit>
</persistence>
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>perso.damazo</groupId>
<artifactId>myapp</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>my-app</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-server</artifactId>
<version>1.8</version>
</dependency>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-json</artifactId>
<version>1.8</version>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>persistence-api</artifactId>
<version>1.0.2</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.3.6.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.31</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>my-app</finalName>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>maven-jetty-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
【问题讨论】：
-
你试过删除依赖
persistence-api吗？ -
感谢您的回复。为什么？我做到了，我知道我有一个不同的错误：
javax.persistence.PersistenceException: Unable to build entity manager factory -
堆栈跟踪的其余部分是什么？你能用它更新你的问题吗？
-
尽管我不能说异常必须与它完全相关，但您的 url 是错误的，它应该是：
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/tink" />。 -
非常感谢 arberio 和 ujulu。有人可以解释依赖的问题是什么，因为我不完全理解？