严重：RuntimeException 无法映射到响应，重新抛出到 HTTP 容器 java.lang.NullPointerException

Question

我正在尝试整合 spring 和 restful，我得到 NullPointer 异常

这是堆栈跟踪

严重：无法将 RuntimeException 映射到响应，重新抛出到 HTTP 容器 java.lang.NullPointerException 在 com.ggk.keshav.RestWebserviceController.getAllPerson(RestWebserviceController.java:60) 在 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 在 sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 在 sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 在 java.lang.reflect.Method.invoke(Method.java:483) 在 com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60) 在 com.sun.jersey.server.impl.model.method.dispatch.Abs​​tractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185) 在 com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75) 在 com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288) 在 com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) 在 com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108) 在 com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) 在 com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84) 在 com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469) 在 com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400) 在 com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349) 在 com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339) 在 com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416) 在 com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537) 在 com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:699) 在 javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) 在 org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 在 org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:233） 在 org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:191） 在 org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:127） 在 org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:102） 在 org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:109） 在 org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:298） 在 org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857) 在 org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) 在 org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) 在 java.lang.Thread.run(Thread.java:745)

这里是 web.xml

<!-- The definition of the Root Spring Container shared by all Servlets 
    and Filters -->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath*:root-context2.xml</param-value>
</context-param>

<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Processes application requests -->
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>appServlet</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>


<servlet>
    <servlet-name>jersey-serlvet</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>com.sun.jersey.config.property.packages</param-name>
        <param-value>com.ggk.keshav</param-value>
    </init-param>
    <init-param>
        <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
        <param-value>true</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>jersey-serlvet</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

这是我的 spring 配置文件

infrastructure -->

<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />
<tx:annotation-driven transaction-manager="transactionManager" />
<context:component-scan base-package="com.ggk" />

<!-- Handles HTTP GET requests for /resources/** by efficiently serving 
    up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />

<!-- Resolves views selected for rendering by @Controllers to .jsp resources 
    in the /WEB-INF/views directory -->
<beans:bean
    class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <beans:property name="prefix" value="/WEB-INF/views/" />
    <beans:property name="suffix" value=".jsp" />
</beans:bean>


<beans:bean
    class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />
<annotation-driven />
<context:annotation-config />

<beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
    destroy-method="close">
    <beans:property name="driverClassName" value="org.h2.Driver" />
    <beans:property name="url" value="jdbc:h2:~/name" />
    <beans:property name="username" value="sa" />

</beans:bean>

<!-- Hibernate 4 SessionFactory Bean definition -->
<beans:bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <beans:property name="dataSource" ref="dataSource" />
    <beans:property name="annotatedClasses">
        <beans:list>
            <beans:value>com.ggk.domain.Person</beans:value>
        </beans:list>
    </beans:property>
    <beans:property name="hibernateProperties">
        <beans:props>
            <beans:prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect
            </beans:prop>
            <beans:prop key="hibernate.show_sql">true</beans:prop>
            <beans:prop key="hbmdl.auto">create</beans:prop>
        </beans:props>
    </beans:property>
</beans:bean>




<beans:bean id="transactionManager"
    class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <beans:property name="sessionFactory"
        ref="sessionFactory" />
</beans:bean>

这是我的控制器

public class WebserviceController {

@Autowired
PersonService personService;

@RequestMapping(value = "/", method =RequestMethod.GET)
public Track getTrack(){
    Track track = new Track();
    track.setSinger("keshav shelar");
    track.setTitle("Chaha");

    return track;

}


@RequestMapping("/person")
@ResponseBody
public Person getPerson(){
    System.out.println("Control in webservice controller");
    return personService.getPersonById(69);

}



@RequestMapping(value="/getAll")
@ResponseBody
public List<Person> getAllPersons(){
    System.out.println("Control in webservice controller");
    return personService.getAllPerons();

}

这里是服务类

@Service
public class PersonServiceimpl implements PersonService {

    @Autowired
    private PersonDao personDaoImpl;

    @Override
    @Transactional
    public int addPerson(Person person) {
        return personDaoImpl.addPerson(person);
    }

    @Override
    @Transactional
    public int updatePerson(Person person) {
        return personDaoImpl.updatePerson(person);
    }

    @Override
    @Transactional
    public int removePeron(List<Integer> personIds) {
        return personDaoImpl.removePeron(personIds);
    }

    @Override
    @Transactional
    public List<Person> getAllPerons() {
        System.out.println("getting alla persons");
        return personDaoImpl.getAllPerons();
    }

    @Override
    @Transactional
    public Person getPersonById(int id) {
        return personDaoImpl.getPersonById(id);
    }

}

我已经配置了 bean PersonService 并一直在自动装配它，但它仍然显示为 null

Answer 1

IProductsDao dao = new ProductsDaoImpl();

不要在serviceImpl构造函数中创建daoImpl的对象，而是尝试单独创建。它对我有用。

Answer 2

您是否将@Component 或@Service 放入您的personService 课程中？