0

我在使用which return的Persist()方法时遇到问题，这是我的代码：EntityManagerNullPointerExpception

@Repository("chainDao")
public class ChainDaoImpl implements ChainDao{

    private EntityManager em;

    @PersistenceContext(unitName="hibernatePersistenceUnit")
    public void setEntityManager(EntityManager em) {
    this.em = em;
    }

    public int saveChain(Chain chain) {
        em.persist(chain);
        return 0;
    }
}

期望符合em.persist(chain)

这是我的persistence.xml

<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">

<persistence-unit name="hibernatePersistenceUnit" transaction-type="RESOURCE_LOCAL">
<properties>
<property name="hibernate.hbm2ddl.auto" value="none" />
</properties>
</persistence-unit>

</persistence>

和片段applicationContext.xml

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close"
p:driverClass="${database.driver}"
p:jdbcUrl="${database.url}"
p:user="${database.user}"
p:password="${database.password}"
p:acquireIncrement="5"
p:idleConnectionTestPeriod="60"
p:maxPoolSize="100"
p:maxStatements="50"
p:minPoolSize="10" />
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" >
<property name="persistenceXmlLocation" value="classpath*:META-INF/persistence.xml"></property>
<property name="persistenceUnitName" value="hibernatePersistenceUnit" />
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" >
<property name="showSql" value="true"/>
</bean>
</property>
</bean>

痕迹：

java.lang.NullPointerException: null
    at pl.postgresql.jpa.dao.ChainDaoImpl.saveCaChain(ChainDaoImpl.java:33) ~[CaChainDaoImpl.class:na]
    at pl.postgresql.jpa.service.StorageServiceImpl.addChain(StorageServiceImpl.java:50) ~[StorageServiceImpl.class:na]
    at pl.camel.jms.service.InputDatabaseServiceImpl.inputChain(InputDatabaseServiceImpl.java:48) ~[InputDatabaseServiceImpl.class:na]
    at pl.camel.jms.connector.EndpointHelper.run(EndpointHelper.java:49) ~[EndpointHelper.class:na]
    at pl.ws.spring.endpoint.CaEndpoint.getCAChain(CaEndpoint.java:63) ~[CaEndpoint.class:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_09]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_09]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_09]
    at java.lang.reflect.Method.invoke(Method.java:601) ~[na:1.7.0_09]
    at org.springframework.ws.server.endpoint.MethodEndpoint.invoke(MethodEndpoint.java:134) ~[spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.server.endpoint.adapter.DefaultMethodEndpointAdapter.invokeInternal(DefaultMethodEndpointAdapter.java:229) ~[spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.server.endpoint.adapter.AbstractMethodEndpointAdapter.invoke(AbstractMethodEndpointAdapter.java:53) ~[spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.server.MessageDispatcher.dispatch(MessageDispatcher.java:233) [spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.server.MessageDispatcher.receive(MessageDispatcher.java:173) [spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.transport.support.WebServiceMessageReceiverObjectSupport.handleConnection(WebServiceMessageReceiverObjectSupport.java:88) [spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.transport.http.WebServiceMessageReceiverHandlerAdapter.handle(WebServiceMessageReceiverHandlerAdapter.java:59) [spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.ws.transport.http.MessageDispatcherServlet.doService(MessageDispatcherServlet.java:221) [spring-ws-core-2.1.1.RELEASE.jar:na]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641) [servlet-api.jar:na]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) [servlet-api.jar:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) [catalina.jar:7.0.30.A]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) [catalina.jar:7.0.30.A]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222) [catalina.jar:7.0.30.A]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123) [catalina.jar:7.0.30.A]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [catalina.jar:7.0.30.A]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) [catalina.jar:7.0.30.A]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) [catalina.jar:7.0.30.A]
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929) [catalina.jar:7.0.30.A]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) [catalina.jar:7.0.30.A]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) [catalina.jar:7.0.30.A]
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002) [tomcat-coyote.jar:7.0.30.A]
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585) [tomcat-coyote.jar:7.0.30.A]
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310) [tomcat-coyote.jar:7.0.30.A]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [na:1.7.0_09]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [na:1.7.0_09]
    at java.lang.Thread.run(Thread.java:722) [na:1.7.0_09]

任何线索我错过了什么？

4

1 回答 1

2

注入的实体管理器只是一个代理。实际的实体管理器实现是在运行时基于@Transactional与使用实体管理器的方法相关联的注释中的传播属性值注入的。因此，将方法saveChain与@Transactional注释关联如下。

@Transactional
public int saveChain(Chain chain) {
    em.persist(chain);
    return 0;
}

强烈建议仔细阅读此注释的文档并将注释属性设置为与您的用例相关的值。

编辑：

spring DI 框架似乎没有setEntityManager像属性名称那样选择设置器em。您可能希望将属性重命名em为entityManager或设置器重命名setEntityManager为setEm或将@PersistenceContext注释移动到属性上并尝试。

于 2012-12-06T10:25:30.477 回答