Question

我遇到了这个错误：

 [WARN] Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract void ne.projl.client.service.ProjService.testdao(java.lang.Integer) throws java.lang.IllegalArgumentException' threw an unexpected exception: java.lang.NullPointerException
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:389)

..... .....

Caused by: java.lang.NullPointerException
    at ne.projl.server.AbstractDAO.findById(AbstractDAO.java:37)

第37行：return getEntityManager().find(entityClass, id);

的web.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
     xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
                http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
                http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
                http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <context:annotation-config />

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
    <display-name>Geomajas GWT face example application</display-name>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            classpath:org/geomajas/spring/geomajasContext.xml
            classpath:org/geomajas/plugin/rasterizing/DefaultRasterizedPipelines.xml
            WEB-INF/applicationContext.xml
<!--            WEB-INF/applicationContext2.xml -->
<!--            WEB-INF/layer*.xml -->
<!--            WEB-INF/map*.xml -->
            WEB-INF/layerOsm.xml
            WEB-INF/mapOsm.xml
<!--            WEB-INF/applicationContext2.xml -->

       </param-value>
    </context-param>


    <filter>
        <filter-name>CacheFilter</filter-name>
        <filter-class>org.geomajas.servlet.CacheFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>CacheFilter</filter-name>
        <url-pattern>*</url-pattern>
    </filter-mapping>

    <listener>
        <listener-class>org.geomajas.servlet.PrepareScanningContextListener</listener-class>
    </listener>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <listener>
        <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>GeomajasServiceServlet</servlet-name>
        <servlet-class>org.geomajas.gwt.server.GeomajasServiceImpl</servlet-class>
    </servlet>

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath*:META-INF/geomajasWebContext.xml</param-value>
            <description>Spring Web-MVC specific (additional) context files.</description>
        </init-param>
        <load-on-startup>3</load-on-startup>
    </servlet>

<!-- SpringGwt remote service servlet --> 
    <servlet>
        <servlet-name>springGwtRemoteServiceServlet</servlet-name>
        <servlet-class>org.spring4gwt.server.SpringGwtRemoteServiceServlet</servlet-class>
        <init-param>
        <param-name>contexConfigLocation</param-name>
        <param-value>WEB-INF/applicationContext2.xml</param-value>
        <description>j</description>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>GeomajasServiceServlet</servlet-name>
        <url-pattern>/showcase/geomajasService</url-pattern>
    </servlet-mapping>

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/d/*</url-pattern>
    </servlet-mapping>



    <servlet-mapping>
        <servlet-name>springGwtRemoteServiceServlet</servlet-name>
        <url-pattern>/showcase/springGwtServices/test</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>

</web-app>

The file applicationContext2.xml below .

我感觉我没有检测到我在applicationContext2.xml中声明的内容，因为如果我没有放置上下文：component-scan base-package =“ne.projl。*”/＆gt;在applicationContext.xml中（没有2）它没有检测到我的带注释的serviceimpl。

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
     xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
                http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
                http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
                http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <context:annotation-config />

<tx:annotation-driven transaction-manager="transactionManager" /> 
<context:component-scan base-package="ne.projl.*" />
<!--    <context:component-scan base-package="FULLY QUALIFIED" /> -->

<bean class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean" id="entityManagerFactory">
        <property name="persistenceUnitName" value="MyPUnit" />
    </bean>

    <bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>


</beans>

EDIT1：

@Repository("poiCategDAO")
public class PoiCategDAO extends AbstractDAO<Integer,PoiCateg> {
    @PersistenceContext(unitName = "ProjPUnit")
    EntityManager entityManager;

    //@Override
    protected EntityManager getEntityManager() {
        return entityManager;
    }


}

Answer 1

错误表明您的EntityManager为空。你是如何设置它的？

如果要注入它，请包含执行注入的配置文件，以及如何访问注入的类。

spring和web.xml以及servlet调度问题

1 个答案: