Ошибка приведения класса с использованием spring и hibernate: com.w2e.model.Session не может быть приведен к com.w2e.model.Session - PullRequest
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Ошибка приведения класса с использованием spring и hibernate: com.w2e.model.Session не может быть приведен к com.w2e.model.Session

1 голос
/ 07 мая 2020

Я использую Spring и спящий режим в недавнем проекте и не могу обойти исключение приведения класса всякий раз, когда я использую stream () в списке сущностей. Я не уверен, проблема ли это в spring или это как-то связано с взаимодействием спящего режима с spring. Я новичок в spring и hibernate, поэтому я не уверен, есть ли что-то basi c, которое мне не хватает. Вот ошибка, которую я получаю: 

  java.lang.ClassCastException: com.w2e.model.Session cannot be cast to com.w2e.model.Session
    at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_71]
    at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1374) ~[na:1.8.0_71]
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_71]
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_71]
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_71]
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:1.8.0_71]
    at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) ~[na:1.8.0_71]
    at com.w2e.services.SessionService.get(SessionService.java:30) ~[classes/:na]
    at com.w2e.controllers.CourseResource.getSession(CourseResource.java:24) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_71]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_71]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_71]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_71]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.31.jar:9.0.31]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.31.jar:9.0.31]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.4.RELEASE.jar:5.2.4.RELEASE

Вот мой файл 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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.in28minutes.fullstack.springboot.maven.crud</groupId>
    <artifactId>spring-boot-fullstack-crud-full-stack-with-maven</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-fullstack-crud-full-stack-with-maven</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-version>5.1.3.RELEASE</spring-version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>5.2.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>com.google.maps</groupId>
            <artifactId>google-maps-services</artifactId>
            <version>0.11.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.3.7.Final</version>
        </dependency>
        <dependency>
            <groupId>org.liquibase</groupId>
            <artifactId>liquibase-core</artifactId>
            <version>3.4.1</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.liquibase</groupId>
                <artifactId>liquibase-maven-plugin</artifactId>
                <version>3.4.1</version>
                <configuration>
                    <propertyFile>src/main/resources/liquibase.properties</propertyFile>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.liquibase.ext</groupId>
                        <artifactId>liquibase-hibernate4</artifactId>
                        <version>3.5</version>
                    </dependency>
                    <dependency>
                        <groupId>org.springframework.data</groupId>
                        <artifactId>spring-data-jpa</artifactId>
                        <version>1.7.3.RELEASE</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

Я использую следующий объект: 

package com.w2e.model;

import javax.persistence.*;

@Entity
@Table(name = "session")
public class Session{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "completions")
    private int completions;

    public Session(int completions){
        this.completions=completions;
    }

    //For Hybernate
    public Session(){}

    public int getCompletions() {
        return completions;
    }

    public void setCompletions(int completions) {
        this.completions = completions;
    }

    public Long getId() {
        return id;
    }
}

Вот мой сервис: 

package com.w2e.services;

import com.w2e.model.Session;
import com.w2e.repository.SessionRepository;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.stream.Collectors;

import static java.util.Objects.requireNonNull;

@Service
public class SessionService {

    private final SessionRepository sessionRepository;

    public SessionService(SessionRepository sessionRepository) {
        this.sessionRepository = requireNonNull(sessionRepository);
    }

    public List<Long> get(){
        return sessionRepository.get().stream().map(Session::getId).collect(Collectors.toList());
    }
}

репозиторий: 

package com.w2e.repository;

import com.w2e.model.Session;
import org.hibernate.HibernateException;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.springframework.stereotype.Repository;

import java.util.ArrayList;
import java.util.List;

@Repository
public class SessionRepository{
    private final SessionFactory factory;

    public SessionRepository(SessionFactory factory) {
        this.factory=factory;
    }

    public List<Session> get() {
        org.hibernate.Session session = factory.openSession();
        Transaction tx = null;
        List<Session> e = new ArrayList<>();
        try {
            tx = session.beginTransaction();
            String query = "FROM Session";
            e.addAll(session.createQuery(query, Session.class).getResultList());
        } catch (HibernateException exp) {
            if (tx!=null) tx.rollback();
            exp.printStackTrace();
        } finally {
            session.close();
        }

        return e;
    }
}

Остальной контроллер: 

package com.w2e.controllers;

import com.w2e.services.SessionService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@CrossOrigin(origins = { "http://localhost:3000", "http://localhost:4200", "http://localhost:8081" })
@RestController
public class CourseResource {

    @Autowired
    private SessionService sessionService;

    @GetMapping("/session")
    public List<Long> getSession(@PathVariable long id) {
        return sessionService.get();
    }

}

Я инициализирую спящий режим и пружину, используя: 

@SpringBootApplication
public class SpringBootFullstackCrudFullStackWithMavenApplication {

    public static SessionFactory factory;

    public static void main(String[] args) {
        try {
            Configuration config = new Configuration()
                    .addAnnotatedClass(Session.class)
                    .configure("hibernate.cfg.xml");
            factory = config.buildSessionFactory();

        } catch (Throwable ex) {
            System.err.println("Failed to create sessionFactory object." + ex);
            throw new ExceptionInInitializerError(ex);
        }

        SpringApplication.run(SpringBootFullstackCrudFullStackWithMavenApplication.class, args);
    }

}

1 Ответ

0 голосов
/ 07 мая 2020

Вероятно, изменение имени класса вместо использования того же имени Spring для объекта Session могло бы помочь более легко определить проблему.

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