以下是名为Class的实体:
package az.bank.entities;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table (name = "cards")
public class Card implements Serializable{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String cardHolder;
private String cardNumber;
private String cardPassword;
private String expiryYear;
private String expiryMonth;
private String cardType;
private double cardBalance;
}
这是我的persistence.xml文件:
<?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="BankServicePU" transaction-type="JTA">
<jta-data-source>jdbc/BankService</jta-data-source>
<class>az.bank.entities.Card</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/cards" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="root" />
<property name="javax.persistence.schema-generation.database.action" value="create"/>
</properties>
</persistence-unit>
</persistence>
我已经创建了名为jdbc/BankService的连接池和名为cards的mySQL方案。但当我部署并运行程序时,它不会在该方案中创建表。请帮助我做了什么错事。
最佳答案
我想在您的例子中,您没有初始化EntityManagerFactory
,这意味着您的eclipseline没有接收到创建表的命令,甚至没有连接到DB。
在您的情况下,您可以尝试使用ServletContextListener
,它必须与您的web.xml
文件重新酯化。
快速示例:
web.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<listener>
<listener-class>
com.mberazouski.stackoverflow.AppServletContextListener
</listener-class>
</listener>
</web-app>
启动Servlet3.0时,只需使用@WebListener注释,而不用在
web.xml
中注册。AppServletContextListener.java
package com.mberazouski.stackoverflow;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class AppServletContextListener implements ServletContextListener {
private static EntityManagerFactory emf;
public void contextInitialized(ServletContextEvent event) {
emf = Persistence.createEntityManagerFactory("default");
createEntityManager();
}
public void contextDestroyed(ServletContextEvent event) {
emf.close();
}
public static EntityManager createEntityManager() {
if (emf == null) {
throw new IllegalStateException("Context is not initialized yet.");
}
return emf.createEntityManager();
}
}
所以你的
persistence.xml
绝对有效。改编成我的域模型文件如下:本地资源
您可以通过
RESOURCE_LOCAL
配置连接。<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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">
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
<class>com.mberazouski.stackoverflow.domain.Cards</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/rsreu"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="root"/>
<property name="javax.persistence.schema-generation.database.action" value="create"/>
</properties>
</persistence-unit>
</persistence>
jta数据源
在这种情况下,所有配置都将从tomcat的
Resource
块中获取:<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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">
<persistence-unit name="default" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>java:comp/env/jdbc/EclispeLinkDB</jta-data-source>
<class>com.mberazouski.stackoverflow.domain.Cards</class>
<properties>
<property name="javax.persistence.schema-generation.database.action" value="create"/>
</properties>
</persistence-unit>
</persistence>
tomcat启动的输出:
但我也建议你看看
spring
的方向。使用it初始化器方法,您可以直接从配置文件初始化EntityManagerFactory
。applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="emf" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean ">
<property name="persistenceUnitName" value="default"/>
</bean>
</beans>
希望这会有帮助。