关于我的 EclipseLink 和 Spring(MVC 和 spring-data)版本 3.1.1 设置的另一个问题:
我正在尝试根据 this article 在不使用 persistence.xml 文件的情况下让 JPA 工作。文章中写道:
Usually, JPA defines a persistence unit through the META-INF/persistence.xml file. Starting with Spring 3.1, this XML file is no longer necessary – the LocalContainerEntityManagerFactoryBean now supports a ‘packagesToScan’ property where the packages to scan for @Entity classes can be specified.
The persistence.xml file was the last piece of XML to be removed – now, JPA can be fully set up with no XML.
据我了解，如果要使用 persistence.xml 文件，则应在此处声明所有实体类。但是，我尝试改用 packagesToScan 属性。下面是完整的启动日志以及向 servlet 发出一个请求(最终尝试在数据库中创建新用户)后产生的错误。它似乎没有意识到 User 对象是一个实体。由于我对 Spring 的经验很少，我想知道是否有人首先可以发现我犯的错误，但除此之外，知道调试它的最佳方法。我想知道 EntityManagerFactory 识别了哪些 Entity 对象。
我的备份选项是切换到使用 persistence.xml(实际上还没有尝试过)，但如果可能的话我想摆脱它(少一个需要担心的 XML 文件)。
更新:根据 Sean Patrick Floyd 的回答，对entityManagerFactory 进行建议的配置更改后，我更新了错误日志，但这并没有解决主要问题。我还尝试了一种替代方法，通过创建 persistence.xml 文件(旧的且更常见的方法)来实现此目的，并在我访问的 servlet 中添加一小段测试代码以启动此操作功能。 现在我的 servlet 中有这段代码:
User user = new User();
user.setFirstName("John");
user.setLastName("Doe");
// user = userService.addUser(user);
EntityManagerFactory emf = Persistence.createEntityManagerFactory("proxiPU");
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
em.persist(user);
em.getTransaction().commit();
em.close();
emf.close();
这个 persistence.xml 文件:
<?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="proxiPU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>com.proxi.user.User</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="eclipselink.jdbc.driver" value="org.hsqldb.jdbcDriver"/>
<property name="eclipselink.jdbc.url" value="jdbc:hsqldb:file:\Users\nly31175\hsqldb;shutdown=true"/>
<property name="eclipselink.jdbc.user" value="proxi"/>
<property name="eclipselink.jdbc.password" value=""/>
<property name="eclipselink.target-database" value="org.eclipse.persistence.platform.database.HSQLPlatform"/>
<property name="eclipselink.logging.level" value="FINEST"/>
<property name="eclipselink.orm.throw.exceptions" value="true"/>
<property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>
<property name="eclipselink.ddl-generation.output-mode" value="database"/>
</properties>
</persistence-unit>
</persistence>
这实际上是有效的，所以我现在想知道这是否是 EntityManagerFactory 初始化方式的问题或类似的问题。我已经包含了 UserService 类的代码，该类应该执行与数据库相关的操作。
这是完整的启动日志(包括错误):
INFO: Reloading Context with name [/proxi] is completed
INFO : com.proxi.controller.HomeController - Welcome home! The client locale is en_GB
[EL Info]: 2012-04-26 15:17:35.066--ServerSession(313687096)--Thread(Thread[http-bio-8980-exec-3,5,main])--EclipseLink, version: Eclipse Persistence Services - 2.2.0.v20110202-r8913
[EL Config]: 2012-04-26 15:17:35.079--ServerSession(313687096)--Connection(1182807222)--Thread(Thread[http-bio-8980-exec-3,5,main])--connecting(DatabaseLogin(
platform=>HSQLPlatform
user name=> ""
connector=>JNDIConnector datasource name=>null
))
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - checkpointClose start
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - checkpointClose end
[EL Config]: 2012-04-26 15:17:36.016--ServerSession(313687096)--Connection(1257700692)--Thread(Thread[http-bio-8980-exec-3,5,main])--Connected: jdbc:hsqldb:file:\Users\nly31175\hsqldb;shutdown=true
User: proxi
Database: HSQL Database Engine Version: 2.2.6
Driver: HSQL Database Engine Driver Version: 2.2.6
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - Database closed
[EL Config]: 2012-04-26 15:17:36.365--ServerSession(313687096)--Connection(385835848)--Thread(Thread[http-bio-8980-exec-3,5,main])--connecting(DatabaseLogin(
platform=>HSQLPlatform
user name=> ""
connector=>JNDIConnector datasource name=>null
))
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - checkpointClose start
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - checkpointClose end
[EL Config]: 2012-04-26 15:17:36.877--ServerSession(313687096)--Connection(603544782)--Thread(Thread[http-bio-8980-exec-3,5,main])--Connected: jdbc:hsqldb:file:\Users\nly31175\hsqldb;shutdown=true
User: proxi
Database: HSQL Database Engine Version: 2.2.6
Driver: HSQL Database Engine Driver Version: 2.2.6
INFO : hsqldb.db.HSQLDB36EB6EA7CB.ENGINE - Database closed
[EL Info]: 2012-04-26 15:17:37.328--ServerSession(313687096)--Thread(Thread[http-bio-8980-exec-3,5,main])--file:/C:/Users/nly31175/workspace/spring/.metadata/.plugins/org.eclipse.wst.server.core/tmp1/wtpwebapps/proxi/WEB-INF/classes/_default login successful
Apr 26, 2012 3:17:37 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [appServlet] in context with path [/proxi] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: Object: com.proxi.user.User@5ca3ce3f is not a known entity type.] with root cause
java.lang.IllegalArgumentException: Object: com.proxi.user.User@5ca3ce3f is not a known entity type.
at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4128)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:406)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:365)
at $Proxy23.persist(Unknown Source)
at com.proxi.user.UserService.save(UserService.java:27)
at com.proxi.user.UserService.addUser(UserService.java:39)
at com.proxi.controller.HomeController.home(HomeController.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:964)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
root-context.xml 文件:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
<!-- Root Context: defines shared resources visible to all other web components -->
<bean id="userService" class="com.proxi.user.UserService" >
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<!-- Starting with Spring 3.1, the persistence.xml XML file is no longer
necessary. The LocalContainerEntityManagerFactoryBean now supports a ‘packagesToScan’
property where the packages to scan for @Entity classes can be specified. -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="jpaDialect" ref="jpaDialect" />
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.proxi.user" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
<property name="showSql" value="true" />
<property name="generateDdl" value="true" />
<property name="databasePlatform" value="org.eclipse.persistence.platform.database.HSQLPlatform" />
</bean>
</property>
<property name="loadTimeWeaver">
<bean class="org.springframework.instrument.classloading.SimpleLoadTimeWeaver" />
</property>
</bean>
<bean id="jpaDialect" class="org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect " />
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.hsqldb.jdbcDriver" />
<property name="url" value="jdbc:hsqldb:file:\Users\nly31175\hsqldb;shutdown=true" />
<property name="username" value="proxi" />
<property name="password" value="" />
</bean>
<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
</beans>
User.java类:
/**
*
*/
package com.proxi.user;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Table;
import javax.persistence.Id;
/**
* Represents an application user.
*/
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "first_name")
private String firstName;
@Column(name = "last_name")
private String lastName;
// /////// GETTERS AND SETTERS ///////////
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
这是UserService.java
package com.proxi.user;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import org.springframework.transaction.annotation.Transactional;
/**
* Performs user related operations.
*
*/
public class UserService {
@PersistenceUnit
private EntityManagerFactory entityManagerFactory;
@Transactional
public User save(User user) {
EntityManager entityManager = entityManagerFactory.createEntityManager();
if (user.getId() == null) {
entityManager.persist(user);
return user;
} else {
return entityManager.merge(user);
}
}
public User findUser(String userid) {
return null;
}
public User addUser(User user) {
return save(user);
}
// /////////////////////// GETTERS AND SETTERS //////////////////////
public EntityManagerFactory getEntityManagerFactory() {
return entityManagerFactory;
}
public void setEntityManagerFactory(EntityManagerFactory entityManagerFactory) {
this.entityManagerFactory = entityManagerFactory;
}
}
最佳答案
Internal Exception: java.sql.SQLSyntaxErrorException: object name already exists: USER in statement [CREATE TABLE user (id BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1, INCREMENT BY 1) NOT NULL, first_name VARCHAR(255), last_name VARCHAR(255), PRIMARY KEY (id))]
这似乎是问题所在:Spring/EclipseLink 正在尝试创建一个已经存在的表。
尝试从 xml 上下文中删除此行:
<property name="generateDdl" value="true" />
关于java - Spring 实体 bean 未知。使用新的 Spring 3.1 packagesToScan 属性并且没有 persistence.xml，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10331490/