Не удалось создать объект типа в веб-приложении Java

Question

Я работал над Java-приложением и обнаружил проблему, на которую не могу найти ответ.Мое приложение представляет собой базу данных для студентов в postgresql, приложение сделано в maven с шаблоном MCV, а для веб-части я использую Spring и hibernate, так как IDE использует Intellij.

Я могу запустить его безпроблема, но при доступе к странице localhost я получаю следующую ошибку:

"Произошла непредвиденная ошибка (тип = Внутренняя ошибка сервера, статус = 500). Не удалось извлечь ResultSet; SQL [н / д]; вложенным исключением является org.hibernate.exception.SQLGrammarException: не удалось извлечь ResultSet "

И в результате я получаю следующую ошибку:

" 2019-04-1720: 38: 43.283 ОШИБКА 14120 --- [nio-8010-exec-7] oaccC [. [. [/]. [DispatcherServlet]: Servlet.service () для сервлета [dispatcherServlet] в контексте с исключением пути path [][Ошибка обработки запроса; вложенное исключение - org.springframework.dao.InvalidDataAccessResourceUsageException: не удалось извлечь ResultSet; SQL [n / a]; вложенное исключение - org.hibernate.exception.SQLGrammarException: couЯ не извлекаю ResultSet] с первопричиной org.postgresql.util.PSQLException: ОШИБКА: отношение "учитель" не существует "

Я не могу понять, почему отношения не существуют, так как у меня есть @ManyToOneна столе это относится к учителю, а в postgresql такие же отношения.

Мой класс модели для учителя:

package project.M.Entities;

import javax.persistence.*; import java.io.Serializable;

@Entity @Table(name = "Teacher") public class Teacher implements
Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    @Column(name="name", nullable = false)
    private String name;
    @Column(name="address", nullable = true)
    private String address;
    @Column(name="email",nullable = false)
    private String email;
    @Column(name="age")
    private Integer age;
    @Column(name="passsword",nullable = false)
    private String password;

    public Teacher(Integer idTask, String description, String filepath, String str, String ema, Integer it) { }


        public Teacher(int id, String name, String password, String address, String email, int age) {
            this.id = id;
            this.name = name;
            this.address = address;
            this.email = email;
            this.age = age;
            this.password = password;
        }

        public Teacher( String name,String password, String address, String email, int age) {
            this.name = name;
            this.address = address;
            this.email = email;
            this.age = age;
                this.password = password;
        }


    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", address='" + address + '\'' +
                ", email='" + email + '\'' +
                ", age=" + age +
                ", password='" + password + '\'' +
                '}';
    } }

И он связан с моим классом курса, для которого модель

package project.M.Entities; import javax.persistence.Column;
import javax.persistence.Entity; import
javax.persistence.GeneratedValue; import
javax.persistence.GenerationType; import javax.persistence.Id; import
javax.persistence.JoinColumn; import javax.persistence.ManyToOne;
import javax.persistence.Table; import
javax.validation.constraints.NotNull; import java.io.Serializable;

@Entity @Table(name = "courses") public class Course implements
Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    @Column(name="name",nullable = false)
    private String name;
    //@Column()
    //private Integer TeacherID;
    @ManyToOne
    @JoinColumn(name = "teacherID",referencedColumnName = "id")
    @NotNull
    private project.M.Entities.Teacher teacher;

    public Course(Integer id, String name, Teacher teacher) {
        this.id = id;
        this.name = name;
        this.teacher = teacher;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public project.M.Entities.Teacher getTeacher() {
        return teacher;
    }

    public void setTeacherID(Teacher teacherID) {
        this.teacher = teacherID;
    }

    @Override
    public String toString() {
        return "Course{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", teacher=" + teacher +
                '}';
    } }

Что касается услуги, которую я имею для учителя:

package project.C;

import project.M.Entities.Teacher;
import project.M.Services.TeacherService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.ModelAndView;

import javax.inject.Inject;
import java.util.List;

@Controller
public class TeacherController {

    @Inject
    TeacherService teacherService;

    @RequestMapping(value ="" ,method = RequestMethod.GET)
    public ModelAndView getTeachers()
    {
        List<Teacher> teacherList = teacherService.getAllTeachersWithCourses();


        ModelAndView mav = new ModelAndView("TeacherView");
        mav.addObject("teachersWithCoursesListId", teacherList);

        return mav;

    }
    @RequestMapping(value = "", method = RequestMethod.POST)
    public ModelAndView postTeacher(@ModelAttribute(value = "newTeacher") Teacher newTeacher)
    {
        teacherService.create(newTeacher);
        return new ModelAndView("redirect:teachers");

    }
    @RequestMapping(value ="", method = RequestMethod.DELETE)
    public ModelAndView deleteTeacher(@ModelAttribute(value = "newTeacher") Teacher newTeacher)
    {
        teacherService.delete(newTeacher);

        return new ModelAndView("redirect:teachers");

    }
/*
    @RequestMapping(value = "", method = RequestMethod.POST)
    @ResponseBody
    public void set(@RequestParam("idTeacher") Integer idTask, @RequestParam("name") String description, @RequestParam("password") String filepath, @RequestParam("address") String str, @RequestParam("email") String ema,@RequestParam("age")Integer it){

// assign parameters to taskDocumentEntity by constructor args or setters
        Teacher document = new Teacher(idTask,description,filepath,str,ema,it);
        teacherService.create(document);
    }
    */

}

, а для службы TeacherService у меня есть следующие

package project.M.Services;

import project.M.Entities.Teacher; import
project.M.Repository.TeacherRepository; import java.util.List; import
java.util.Optional;

import javax.inject.Inject;

import org.springframework.stereotype.Service;

@Service public class TeacherService {
    private int count;

    @Inject
    TeacherRepository teacherRepository;

    public List<Teacher> getAllTeachersWithCourses()
    {
        return teacherRepository.findAll();
    }

    public void create(Teacher newTeacher)
    {
        System.out.println("aaaa"+newTeacher);
         teacherRepository.save(newTeacher);
    }
    public void delete(Teacher newTeacher)
    {
         teacherRepository.delete(newTeacher);
    }

   public void update(Teacher old,Teacher st)    {
        if(old==null)
        {
            System.out.println("eror at update");
        }
        else
        {
            teacherRepository.delete(old);
            teacherRepository.save(st);
        }    }

} 

Мой TeacherView, к которому я пытаюсь получить доступ:

  <!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org" xmlns:th1="http://www.w3.org/1999/xhtml">

<head>
    <title>Teachers</title>
    <link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" />
    <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css" rel="stylesheet" />

</head>

<body>


<table  border="1">
    <thead>
    <tr>
        <th>teacher.ID</th>
        <th>teacher.NAME</th>
        <th>teacher.PASSWORD</th>
        <th>teacher.EMAIL</th>
        <th>teacher.AGE</th>
        <th>course entire data</th>
    </tr>
    </thead>
    <tbody>
    <tr th:each="teacher : ${ teachersWithCoursesList }">

        <td th:text="${ teacher.id }">ID</td>
        <td th:text="${ teacher.name }"></td>
        <td th:text="${ teacher.password }"></td>
        <td th:text="${ teacher.email }"></td>
        <td th:text="${ teacher.age }"></td>
        <td th1:text="${ teacher.courses }">
            <p th:each="course: ${ teacher.courses  }">
                <span th:text="${course.id}"></span>
                <span th:text="${course.name}"></span>
            </p>
        </td>

    </tr>
    </tbody>
</table>

<br/>
<br/>
<br/>

<form   th:object="${newTeacher}" method="post">
    <div class="col-sm-12">
        <label>Name</label>
        <input placeholder="Teacher Name" name="name"/>
    </div>
    <div class="col-sm-12">
        <label>Password</label>
        <input placeholder="Teacher password" name="password"/>
    </div>
    <div class="col-sm-12">
        <label>Email</label>
        <input placeholder="Teacher email" name="email"/>
    </div>

    <button type="submit" class = "btn btn-primary">ADD Teacher</button>
</form>

</body>

Моя база данных

Также sql для БД: курс

 -- Table: public."Courses"

-- DROP TABLE public."Courses";

CREATE TABLE public."Courses"
(
    "idCourses" integer NOT NULL,
    "Name" "char"[] NOT NULL,
    "TeacherID" integer NOT NULL,
    CONSTRAINT "Courses_pkey" PRIMARY KEY ("idCourses"),
    CONSTRAINT "teacherID" FOREIGN KEY ("TeacherID")
        REFERENCES public."Teacher" ("idTeacher") MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION
)
WITH (
    OIDS = FALSE
)
TABLESPACE pg_default;

ALTER TABLE public."Courses"
    OWNER to postgres;

-- Index: fki_teacherID

-- DROP INDEX public."fki_teacherID";

CREATE INDEX "fki_teacherID"
    ON public."Courses" USING btree
    ("TeacherID")
    TABLESPACE pg_default;

Учитель

-- Table: public."Teacher"

-- DROP TABLE public."Teacher";

CREATE TABLE public."Teacher"
(
    "idTeacher" integer NOT NULL,
    name "char"[] NOT NULL,
    password "char"[] NOT NULL,
    address "char"[],
    email "char"[] NOT NULL,
    age integer,
    CONSTRAINT "Teacher_pkey" PRIMARY KEY ("idTeacher")
)
WITH (
    OIDS = FALSE
)
TABLESPACE pg_default;

ALTER TABLE public."Teacher"
    OWNER to postgres;

Ученик:

-- Table: public."Student"

-- DROP TABLE public."Student";

CREATE TABLE public."Student"
(
    address "char"[],
    email "char"[] NOT NULL,
    "idStudent" integer NOT NULL,
    name "char"[] NOT NULL,
    password "char"[] NOT NULL,
    age integer,
    CONSTRAINT "Student_pkey" PRIMARY KEY ("idStudent")
)
WITH (
    OIDS = FALSE
)
TABLESPACE pg_default;

ALTER TABLE public."Student"
    OWNER to postgres;

Оценки:

-- Table: public.grades

-- DROP TABLE public.grades;

CREATE TABLE public.grades
(
    "IdCourses" integer NOT NULL,
    "idStudent" integer NOT NULL,
    "Grade" integer,
    "Exam" integer,
    "Midterm" integer,
    "examDate" date,
    "midtermDate" date,
    "Id" bigint NOT NULL,
    CONSTRAINT "IdGrades" PRIMARY KEY ("Id"),
    CONSTRAINT "idCourses" FOREIGN KEY ("IdCourses")
        REFERENCES public."Courses" ("idCourses") MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION,
    CONSTRAINT "idStudent" FOREIGN KEY ("idStudent")
        REFERENCES public."Student" ("idStudent") MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION
)
WITH (
    OIDS = FALSE
)
TABLESPACE pg_default;

ALTER TABLE public.grades
    OWNER to postgres;

-- Index: fki_idCourses

-- DROP INDEX public."fki_idCourses";

CREATE INDEX "fki_idCourses"
    ON public.grades USING btree
    ("IdCourses")
    TABLESPACE pg_default;

-- Index: fki_idStudent

-- DROP INDEX public."fki_idStudent";

CREATE INDEX "fki_idStudent"
    ON public.grades USING btree
    ("idStudent")
    TABLESPACE pg_default;

позднее редактирование: это ошибка после обновления кода с помощью2 отношения:

 org.hibernate.tool.schema.spi.CommandAcceptanceException: Unable to execute command [alter table courses drop constraint FKkhvrych02e4jav7oqoemsf498]
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:63) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:370) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:355) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applyConstraintDropping(SchemaDropperImpl.java:327) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:229) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:153) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:125) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:111) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:137) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:65) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:308) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:483) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:888) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105) ~[spring-context-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) ~[spring-context-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
    at project.Assignment2Application.main(Assignment2Application.java:9) ~[classes/:na]
Caused by: org.postgresql.util.PSQLException: ERROR: relation "courses" does not exist
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2440) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2183) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:308) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:441) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:365) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:307) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.executeCachedSql(PgStatement.java:293) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:270) ~[postgresql-42.2.5.jar:42.2.5]
    at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:266) ~[postgresql-42.2.5.jar:42.2.5]
    at com.zaxxer.hikari.pool.ProxyStatement.execute(ProxyStatement.java:95) ~[HikariCP-3.2.0.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyStatement.execute(HikariProxyStatement.java) ~[HikariCP-3.2.0.jar:na]
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:51) ~[hibernate-core-5.2.1.Final.jar:5.2.1.Final]
    ... 35 common frames omitted

Answer 1

1) Просто позвольте JPA создавать таблицы и DDL для вас.

spring.jpa.generate-ddl
spring.jpa.hibernate.ddl-auto

https://docs.spring.io/spring-boot/docs/current/reference/html/howto-database-initialization.html

2) На странице вы получаете доступ к teacher.courses, но в вашей сущности Teacher нет объекта отношения.

Курс

@ManyToOne(fetch = FetchType.LAZY, optional = false)
@JoinColumn(name = "TeacherID", nullable = false)
private Teacher teacher;

Учитель

@OneToMany(cascade = CascadeType.ALL,
        fetch = FetchType.LAZY,
        mappedBy = "teacher")
private List<Course> courses = new ArrayList<>();

для полного рабочего примера, проверьте https://www.callicoder.com/hibernate-spring-boot-jpa-one-to-many-mapping-example/

Answer 2

В своем курсе вы не соблюдаете соглашение об именовании Java Beans.

У вас есть полевой чайный учитель, getter getTeacher, но setter setTeacherID.

Переименуйте сеттер в setTeacher

Обновление

@ JoinColumn в том же поле неверно.Я вижу Teacher_idTeacher в БД и другие значения в вашем коде

Еще одна вещь, которую нужно проверить, - есть ли у вашего пользователя БД все необходимые права доступа к таблицам, которые вы используете.Если пользователь не имеет доступа к таблице, запрос может быть сгенерирован правильно, но вы все равно получите ошибки грамматики sql

Update2

Любое из следующего:

• проблемы с корпусом.Вы создаете «Учителя», но сгенерированный запрос ищет учителя.См. org.postgresql.util.PSQLException: ОШИБКА: отношение "app_user" не существует

• схема по умолчанию не соответствует общедоступной Изменить схему базы данных, используемую SpringBoot Или укажите схему в @ Table

Кроме того, ваше отображение по-прежнему неверно, имена столбцов id не совпадают с db.