javax.persistence.PersistenceException - JPA+休眠

Question

我是 JPA 的新手，当我尝试运行以下代码时，它显示错误为“cvc-elt.1：找不到元素'persistence'的声明。”

我无法修复这个错误，你能帮我解决这个问题吗？

干杯

拉杰什

Persistance.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="jpa" transaction-type="JTA">

        <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <class>com.optirisk.pojo.Department</class>
        <class>com.optirisk.pojo.Employee</class>

        <properties>
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.connection.username" value="NewsLetter1" />
            <property name="hibernate.connection.password" value="optiindia2012" />
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/orpss_hibernate_prototype" />
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect" />
        </properties>

    </persistence-unit>
</persistence>

Application.java

public class Application {

    private static final String PERSISTENCE_UNIT_NAME = "jpa";
    private static EntityManagerFactory entityManagerFactory;

    public static void main(String[] args) throws Exception {

        entityManagerFactory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);

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

        Department department = new Department();
        department.setDeptName("IT");
        entityManager.persist(department);

        Employee emp1 = new Employee("Peter", "ROB", "454565");
        Employee emp2 = new Employee("Mathew", "Anderson", "222");

        emp1.setDepartment(department);
        emp2.setDepartment(department);

        entityManager.persist(emp1);
        entityManager.persist(emp2);

        entityManager.getTransaction().commit();
        entityManager.close();

    }

}

错误：

Exception in thread "main" javax.persistence.PersistenceException: Invalid persistence.xml.
Error parsing XML (line-1 : column -1): cvc-elt.1: Cannot find the declaration of element 'persistence'.
    at org.hibernate.ejb.packaging.PersistenceXmlLoader.loadURL(PersistenceXmlLoader.java:147)
    at org.hibernate.ejb.packaging.PersistenceXmlLoader.deploy(PersistenceXmlLoader.java:171)
    at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:325)
    at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:58)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:52)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
    at com.jishraa.jpa.Application.main(Application.java:19)

Answer 1

问题是您的 与您的休眠库要求不匹配。复制并粘贴来自可靠示例的带有名称空间 (xmlns) 的整个持久性标记。然后检查您的库版本，如下所示。

来自 hibernate.org：http://hibernate.org/orm/downloads/

支持的 JPA 版本

JPA 1.0: ORM 3.2+
JPA 2.0: ORM 3.5+
JPA 2.1: ORM 4.3+

请注意，较新的 ORM 版本向后兼容较旧的 JPA 版本（例如：ORM 4.3 和 JPA 1.0）。但是，较新的 ORM 版本可能 与旧的 JPA 容器不兼容。

JPA 版本与持久化版本相同。 ORM 是休眠的版本。所以你的持久性文件有<persistence version="2.1" ... >。因此，到目前为止，您只需要以下 hibernate 库和版本（或更高版本）：

WEB-INF/lib/hibernate-entitymanager-4.3.0.Final.jar

或 Maven pom.xml：

<!-- for JPA, use hibernate-entitymanager instead of hibernate-core -->
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>4.3.0.Final</version>
</dependency>

我在这个上花了一大堆时间。我希望我花费的时间可以节省您的时间！

Answer 2

我怀疑您的环境仅支持持久性 2.0。尝试改变：

<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">

收件人：

<persistence 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" version="2.0">

Answer 3

您的 xml 中缺少 <persistence> 元素...检查您发布的 xsd 并使您的 persistence.xml 符合架构。一个简单的例子见this link