对象：不是已知的实体类型。的EclipseLink

Question

我是eclipselink或jpa的新手。我正在关注来自here的eclipselink教程。运行 Test.java 类时，我收到以下异常。我在网络上使用oracle数据库。请帮帮我。

[EL Info]: connection: 2016-09-14 15:13:33.562--ServerSession(271944754)--/file:/D:/Developer/EclipseLink/bin/_TestPersistence login successful
[EL Warning]: metamodel: 2016-09-14 15:13:33.577--The collection of metamodel types is empty. Model classes may not have been found during entity search for Java SE and some Java EE container managed persistence units.  Please verify that your entity classes are referenced in persistence.xml using either <class> elements or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element
Exception in thread "main" java.lang.IllegalArgumentException: Object: Employee [name=Mukesh, email=m@gmail.com , department=Finance] is not a known Entity type.
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4226)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:507)
    at com.assignment.Test.main(Test.java:28)

的persistence.xml

<?xml version="1.0" encoding="UTF-8" ?>
<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" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="TestPersistence"
transaction-type="RESOURCE_LOCAL">
<class>com.assignment.Employee</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="oracle.jdbc.driver.OracleDriver" />
<property name="javax.persistence.jdbc.url"
value="jdbc:oracle:thin:@ipaddress:port/servicename" />
<property name="javax.persistence.jdbc.user" value="username" />
<property name="javax.persistence.jdbc.password"
value="password" />
<!-- EclipseLink should create the database schema automatically -->
<property name="eclipselink.ddl-generation" value="create-tables" />
<property name="eclipselink.ddl-generation.output-mode"
value="database" />
</properties>
</persistence-unit>
</persistence>

Employee.java

package com.assignment;
public class Employee {
        private Long id;
        private String name;
        private String email;
        private String department;

        public Long getId() {
            return id;
        }
        public void setId(Long id) {
            this.id = id;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public String getEmail() {
            return email;
        }
        public void setEmail(String email) {
            this.email = email;
        }
        public String getDepartment() {
            return department;
        }
        public void setDepartment(String department) {
            this.department = department;
        }
        public String toString() {
            return "Employee [name=" + name + ", email=" + email + " , department="
                    + department + "]";
        }
}

Test.java

package com.assignment;

import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

public class Test {
    private static final String PERSISTENCE_UNIT_NAME = "TestPersistence";
      private static EntityManagerFactory factory;
      public static void main(String[] args) {
        factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
        EntityManager em = factory.createEntityManager();
        em.getTransaction().begin();
        Employee emp = new Employee();
        emp.setName("Mukesh");
        emp.setEmail("m@gmail.com");
        emp.setDepartment("Finance");
        em.persist(emp);
        em.getTransaction().commit();
        em.close();
      }
    }

包结构

Answer 1

尝试对import socket import sys import smtplib EMAIL_TO = ["rajiv@domain.com"] EMAIL_FROM = "rajiv@domain.com" EMAIL_SUBJECT = "Test Mail... " msg= {} EMAIL_SPACE = ", " msg['Subject'] = EMAIL_SUBJECT msg['To'] = EMAIL_SPACE.join(EMAIL_TO) msg['From'] = EMAIL_FROM try: mail = smtplib.SMTP_SSL('smtp.bizmail.yahoo.com',465) # # if you are using gmail then use # smtplib.SMTP_SSL('smtp.gmail.com',587) # mail.login("rajiv@domain.com", 'password') # you account email password.. mail.sendmail("rajiv@domain.com", EMAIL_TO, msg.as_string()) mail.quit() except Exception,e: print e finally: print "Error of email sending mail" 类使用javax.persistence.Entity注释。

有关EclipseLink用法的更多信息和示例： https://wiki.eclipse.org/EclipseLink/Examples/JPA

Answer 2

为您的班级提供@Entity注释。您可能还需要主键ID，将@Id指定给其中一个属性。

package com.assignment;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Employee {
        @Id
        private Long id;
        private String name;
        private String email;
        private String department;

        public Long getId() {
            return id;
        }
        public void setId(Long id) {
            this.id = id;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public String getEmail() {
            return email;
        }
        public void setEmail(String email) {
            this.email = email;
        }
        public String getDepartment() {
            return department;
        }
        public void setDepartment(String department) {
            this.department = department;
        }
        public String toString() {
            return "Employee [name=" + name + ", email=" + email + " , department="
                    + department + "]";
        }
}