Oracle DB 的persistence.xml 中的问题

如何解决Oracle DB 的persistence.xml 中的问题

我遇到以下错误：org.xml.sax.SAXParseException;行号：4；列数：77； schema_reference.4：无法读取架构文档“http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd”，因为 1) 找不到文档； 2) 无法读取文件； 3) 文档的根元素不是 xsd:schema。在 com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203) 我的 Persistence.xml 计数如下：

 <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="jpa-Metaservice"
    transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

    <properties>
        <!-- Configuring JDBC properties -->
        <property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@host:1575:sid" />
        <property name="javax.persistence.jdbc.user" value="username" />
        <property name="javax.persistence.jdbc.password" value="password" />
        <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.driver.OracleDriver" />

        <!-- Hibernate properties -->
        <property name="hibernate.show_sql" value="true" />
        <property name="hibernate.format_sql" value="true" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle12cDialect" />
        <property name="hibernate.hbm2ddl.auto" value="none" />

        <!-- 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" />
        <class>com.db.solrsearchSvc.model.ModelObjectsorm</class>
        <class>com.db.solrsearchSvc.model.ModelObjectField</class>
        <class>com.db.solrsearchSvc.model.solrCustomer</class>
    </properties>
</persistence-unit>