Spring MVC / Hibernate：控制器中的自动连线服务为空

时间：2018-11-22 02:15:00

标签： java spring hibernate spring-mvc spring-data-jpa

我正在尝试在@Autowire中@Service到@Controller。这将导致运行时NullPointerException（我尝试在其中使用@Service）。由于某种原因，Spring并未注入依赖项，因此我仍未弄清。似乎不是由于两个主要原因（手动实例化或缺少注释）造成的。

ReviewController：

package group9.movie_reviews.controller;

import group9.movie_reviews.service.impl.ReviewService;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.SessionAttributes;

import javax.annotation.Resource;

@Controller
@RequestMapping("/review")
@SessionAttributes("review")
public class ReviewController {

    @Resource
    private ReviewService reviewService;

    @RequestMapping(method = RequestMethod.GET)
    public String wtf(ModelMap model) {
        model.addAttribute("a", reviewService.getReviews()); // NullPointerException here
        return "index";
    }

}

ReviewService：

package group9.movie_reviews.service;

import group9.movie_reviews.model.ReviewEntity;

public interface ReviewService {

    Iterable<ReviewEntity> getReviews();

    void addReview(String movieName);

}

ReviewServiceImpl：

package group9.movie_reviews.service.impl;

import group9.movie_reviews.model.ReviewEntity;
import group9.movie_reviews.repository.ReviewRepository;
import group9.movie_reviews.service.ReviewService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class ReviewServiceImpl implements ReviewService {

    @Resource
    private ReviewRepository reviewRepository;

    @Override
    public Iterable<ReviewEntity> getReviews() {
        return reviewRepository.findAll();
    }

    @Override
    public void addReview(String movieName) {
        ReviewEntity r = new ReviewEntity();
        r.setMovieName(movieName);
        reviewRepository.save(r);
    }

}

ReviewRepository：

package group9.movie_reviews.repository;

import group9.movie_reviews.model.ReviewEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ReviewRepository extends JpaRepository<ReviewEntity, Integer> {
    ReviewEntity findByMovieName(String movieName);
}

Stacktrace /错误：

Type Exception Report

Message Request processing failed; nested exception is java.lang.NullPointerException

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Root Cause

java.lang.NullPointerException
    group9.movie_reviews.controller.ReviewController.wtf(ReviewController.java:21)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:498)
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

配置文件：

WebConfig：

package group9.movie_reviews.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"group9.movie_reviews"})
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = {"group9.movie_reviews.repository"})
public class WebConfig extends WebMvcConfigurerAdapter {

    @Bean
    public InternalResourceViewResolver resolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/jsp/");
        resolver.setSuffix(".jsp");
        return resolver;
    }

}

WebInit：

package group9.movie_reviews.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@Configuration
public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{RootConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/", "/review"};
    }

}

重新部署异常/堆栈跟踪：

[2018-11-22 02:53:37,857] Artifact movie_reviews:war exploded: Artifact is being deployed, please wait...
22-Nov-2018 02:53:37.878 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.doClose Closing WebApplicationContext for namespace 'dispatcher-servlet': startup date [    Thu Nov 22 02:35:08 GMT 2018]; parent: Root WebApplicationContext
22-Nov-2018 02:53:37.878 WARNING [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.doClose Exception thrown from LifecycleProcessor on context close
 java.lang.IllegalStateException: LifecycleProcessor not initialized - call 'refresh' before invoking lifecycle methods via the context: WebApplicationContext for namespace 'dispatcher-servlet': startup date [Thu Nov 22 02:35:08 GMT     2018]; parent: Root WebApplicationContext
    at org.springframework.context.support.AbstractApplicationContext.getLifecycleProcessor(AbstractApplicationContext.java:416)
    at org.springframework.context.support.AbstractApplicationContext.doClose(AbstractApplicationContext.java:997)
    at org.springframework.context.support.AbstractApplicationContext.close(AbstractApplicationContext.java:956)
    at org.springframework.web.servlet.FrameworkServlet.destroy(FrameworkServlet.java:829)
    at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:1393)
    at org.apache.catalina.core.StandardWrapper.stopInternal(StandardWrapper.java:1729)
    at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:221)
    at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5573)
    at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:221)
    at org.apache.catalina.core.ContainerBase.removeChild(ContainerBase.java:851)
    at org.apache.catalina.startup.HostConfig.unmanageApp(HostConfig.java:1755)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at org.apache.catalina.mbeans.MBeanFactory.removeContext(MBeanFactory.java:792)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:300)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
    at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
    at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
    at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
    at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
    at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
    at sun.reflect.GeneratedMethodAccessor238.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:835)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

22-Nov-2018 02:53:37.880 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.doClose Closing Root WebApplicationContext: startup date [Thu Nov 22 02:35:08 GMT 2018];     root of context hierarchy
22-Nov-2018 02:53:40.095 INFO [RMI TCP Connection(83)-127.0.0.1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of     JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
22-Nov-2018 02:53:40.197 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.ContextLoader.initWebApplicationContext Root WebApplicationContext: initialization started
22-Nov-2018 02:53:40.305 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.prepareRefresh Refreshing Root WebApplicationContext: startup date [Thu Nov 22 02:53:40     GMT 2018]; root of context hierarchy
22-Nov-2018 02:53:40.400 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.loadBeanDefinitions Registering annotated classes: [class     group9.movie_reviews.config.RootConfig]
22-Nov-2018 02:53:40.709 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.ContextLoader.initWebApplicationContext Root WebApplicationContext: initialization completed in 512 ms
22-Nov-2018 02:53:40.713 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.servlet.DispatcherServlet.initServletBean FrameworkServlet 'dispatcher': initialization started
22-Nov-2018 02:53:40.719 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.prepareRefresh Refreshing WebApplicationContext for namespace 'dispatcher-servlet':     startup date [Thu Nov 22 02:53:40 GMT 2018]; parent: Root WebApplicationContext
22-Nov-2018 02:53:40.722 INFO [RMI TCP Connection(83)-127.0.0.1] org.springframework.web.context.support.AnnotationConfigWebApplicationContext.loadBeanDefinitions Registering annotated classes: [class     group9.movie_reviews.config.WebConfig]
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
[2018-11-22 02:53:41,443] Artifact movie_reviews:war exploded: Artifact is deployed successfully
[2018-11-22 02:53:41,443] Artifact movie_reviews:war exploded: Deploy took 3,586 milliseconds

Pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>group9</groupId>
    <artifactId>movie_reviews</artifactId>
    <version>1.0</version>
    <packaging>war</packaging>

    <name>movie_reviews</name>

    <properties>
        <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring-version>4.3.3.RELEASE</spring-version>
        <servlet-version>3.1.0</servlet-version>
        <jstl-version>1.2</jstl-version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring-version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlet-version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring-version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.3.7.Final</version>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.196</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>2.1.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl-version}</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                    <compilerArguments>
                        <endorseddirs>${endorsed.dir}</endorseddirs>
                    </compilerArguments>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

0 个答案:

没有答案
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