部署到tomcat服务器时发生JPA错误

Question

我在netbean（在glassfish服务器上运行）上有一个javaEE应用程序（webapp）。我使用JPA ORM。我在MAVEN上导入了所有正确的jar。当我想在远程服务器（在tomcat上运行）上部署此webapp的WAR文件时，JPA会使其崩溃...

我在服务器上有一个错误500：

_EmployeesManagementApplication2_war_1PeristenceException：没有EntityManager的持久性提供程序，名为com.mycompanyjavax.persistence..0-SNAPSHOTPUjavax.persistence.Persistence.createEntityManagerFactory（Persistence.java:85）javax.persistence.Persistence.createEntityManagerFactory（Persistence.java:54）模型。DataTransaction.（DataTransaction.java:31）控制器。SingleController.doGet（SingleController.java:37）javax.servlet.http.HttpServlet.service（HttpServlet.java:635）javax.servlet.http.HttpServlet.service（HttpServlet.java:742）org.apache.tomcat.websocket.server.WsFilter.do过滤器（WsFilter.java:52）

这是我的pom.xml：

http://maven.apache.org/xsd/maven-4.0.0.xsd"

<groupId>com.mycompany</groupId>
<artifactId>EmployeesManagementApplication2</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>

<name>EmployeesManagementApplication2</name>

<properties>
    <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>eclipselink</artifactId>
        <version>2.5.2</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>org.eclipse.persistence.jpa.modelgen.processor</artifactId>
        <version>2.5.2</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>org.eclipse.persistence.jpa</artifactId>
        <version>2.5.2</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.persistence</groupId>
        <artifactId>javax.persistence-api</artifactId>
        <version>2.2</version>
    </dependency>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>7.0</version>
        <scope>provided</scope>
    </dependency>

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

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
                <compilerArguments>
                    <endorseddirs>${endorsed.dir}</endorseddirs>
                </compilerArguments>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.3</version>
            <configuration>
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.6</version>
            <executions>
                <execution>
                    <phase>validate</phase>
                    <goals>
                        <goal>copy</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${endorsed.dir}</outputDirectory>
                        <silent>true</silent>
                        <artifactItems>
                            <artifactItem>
                                <groupId>javax</groupId>
                                <artifactId>javaee-endorsed-api</artifactId>
                                <version>7.0</version>
                                <type>jar</type>
                            </artifactItem>
                        </artifactItems>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

而这是我的persistence.xml：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" 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">
  <persistence-unit name="com.mycompany_EmployeesManagementApplication2_war_1.0-SNAPSHOTPU" transaction-type="JTA">
    <jta-data-source>java:app/awsrds</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="javax.persistence.schema-generation.database.action" value="create"/>
    </properties>
  </persistence-unit>
</persistence>

我的持久性文件正确地位于resources/META-INF中

非常感谢你

Answer 1

原因是Tomcat不是一个完整JavaEE服务器，它只是一个servlet容器，不提供JPA，Glassfish这样做。如果您希望将JPA与Tomcat一起使用，那么您需要将其作为库包含在您的WAR中。

如果您使用的是纯JPA，而不是任何Eclipselink功能，那么您可以使用TomEE，其中包括ApacheOpenJPA作为JPA的替代提供商。或者，你可以继续使用GlassFish或Payara，其中包括Eclipselink，不需要你将其包括在内。