Java Spring/JPA应用程序搜索不存在的数据库表

我有一个使用JPA作为ORM的Spring应用程序，我认为这是正确的，并且大摇大摆地为我的端点创建了一个漂亮的UI

尝试使用已保存在数据库中的数据发出POST或PUT请求时，我收到一个错误：

Servlet.service() for servlet [dispatcher] in context with path [/api/orgchart] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute statement; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute statement] with root cause

java.sql.SQLSyntaxErrorException: Table 'orgchart_api.employee_department' doesn't exist

很明显，错误来自JPA试图更新

employee\u department

表上的数据，而该表不存在。我遇到的问题是弄清楚为什么JPA试图访问该表

数据流：

大摇大摆的用户界面->用JSON发布请求 ->雇员控制员 ->雇员服务 ->雇员映射器 职业性

package com.nexient.orgchart.data.entity；
导入org.hibernate.validator.constraints.NotEmpty；
导入javax.persistence.*；
导入java.util.Set；
@实体
@表（name=“职务”）
公共类JobTitleEntity扩展了BaseEntity{
@列（name=“name”，unique=true）
@空空如也
私有字符串名称；
@独身癖
私人设定所有权的雇员；
…能手和二传手。。。

部门实体

package com.nexient.orgchart.data.entity；
导入javax.persistence.*；
导入javax.validation.constraints.NotNull；
导入javax.validation.constraints.Size；
导入org.hibernate.validator.constraints.NotEmpty；
导入java.util.HashSet；
导入java.util.Set；
@实体
@表（name=“department”）
公共类DepartmentEntity扩展BaseEntity{
@manytone（fetch=FetchType.EAGER）
@JoinColumn（name=“manager\u id”）
私人雇员实体经理；
@列（name=“name”，nullable=false，length=50，unique=true）
@NotNull
@空空如也
@尺寸（最小值=1，最大值=45）
私有字符串名称；
@manytone（fetch=FetchType.EAGER）
@JoinColumn（name=“家长\部门\ id”，referencedColumnName=“id”）
私人部门实体部门；
@OneToMany（mappedBy=“家长部门”）
私有集部门=新哈希集（0）；
@OneToMany（mappedBy=“部门”）
私有集employees=newhashset（0）；
…能手和二传手。。。

发生这种情况是因为您与

N

员工有

1

部门关系：

@ManyToOne
@JoinColumn(name = "department_id")
private DepartmentEntity department;

您的JPA实现选择使用专用表来支持此关系，而不是使用可为空的列。它显然已自动从相关实体的表名中派生出此关系的

employee\u department

名称

---

使用配置为生成DDL语句并记录所有SQL语句的JPA实现运行应用程序可能会非常有启发性。确切的配置将取决于您选择的JPA提供程序，但由于您使用的是Spring，您可能需要

Spring.JPA.generate DDL=true

和

Spring.JPA。show sql=true

。请参见

您知道我如何防止这种情况发生，还是让创建此表更好？我的帖子似乎运行了一段时间，然后在几个请求后出现了此错误。到目前为止，我唯一能够修复此错误的方法是重置数据库和服务器。要“防止”如果发生这种情况，您必须有效地放弃该点，并手动定义一个

实体

，以替换原始关系/映射。这还意味着对代码的其余部分进行破坏性更改：您将需要额外的存储库来追溯关系。与您的JPA提供商进行斗争以改变其行为/预期是非常必要的当然不是一个好主意。不过，最好调整一下数据库，以便包含关系所需的表。

package com.orgchart.web.controller;

import com.orgchart.model.Employee;
import com.orgchart.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/emps")
public class EmployeeController {

    @Autowired
    EmployeeService employeeService;

    @RequestMapping(method = {RequestMethod.POST, RequestMethod.PUT})
    public Employee createOrUpdateEmployee(@RequestBody Employee employee) {
        return employeeService.storeOrUpdate(employee);
    }

}

package com.nexient.orgchart.service;

import com.nexient.orgchart.data.entity.DepartmentEntity;
import com.nexient.orgchart.data.entity.EmployeeEntity;
import com.nexient.orgchart.data.repository.EmployeeRepository;
import com.nexient.orgchart.mapper.EmployeeMapper;
import com.nexient.orgchart.model.Employee;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.Assert;

import java.util.ArrayList;
import java.util.List;
import java.util.function.Consumer;
import java.util.stream.Collectors;

@Service
public class EmployeeService {

    @Autowired
    private EmployeeRepository employeeRepository;

    @Autowired
    EmployeeMapper employeeMapper;

    public Employee storeOrUpdate(Employee employee) {
        EmployeeEntity employeeEntity = employeeMapper.modelToEntity(employee);
        EmployeeEntity savedEmployeeEntity = employeeRepository.save(employeeEntity);
        Employee employeeModel = employeeMapper.entityToModel(savedEmployeeEntity);
        return employeeModel;
    }

package com.nexient.orgchart.mapper;

import com.nexient.orgchart.data.entity.DepartmentEntity;
import com.nexient.orgchart.data.entity.EmployeeEntity;
import com.nexient.orgchart.data.entity.JobTitleEntity;
import com.nexient.orgchart.model.Department;
import com.nexient.orgchart.model.Employee;
import com.nexient.orgchart.model.JobTitle;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.util.Assert;

@Component
public class EmployeeMapper implements EntityModelMapper<EmployeeEntity, Employee> {

    @Autowired
    private DepartmentMapper departmentMapper;

    @Autowired
    private JobTitleMapper jobTitleMapper;

    @Override
    public EmployeeEntity modelToEntity(Employee employee) {
        Assert.notNull(employee, "Employee model cannot be null.");

        EmployeeEntity employeeEntity = new EmployeeEntity();
        DepartmentEntity departmentEntity = departmentMapper.modelToEntity(employee.getDepartment());
        JobTitleEntity jobTitleEntity = jobTitleMapper.modelToEntity(employee.getJobTitle());
        Employee employeeManager = employee.getManager();

        if (employeeManager != null) {
            EmployeeEntity employeeManagerEntity = modelToEntity(employeeManager);
            employeeEntity.setManager(employeeManagerEntity);
        }

        employeeEntity.setId(employee.getId());
        employeeEntity.setEmail(employee.getEmail());
        employeeEntity.setFirstName(employee.getFirstName());
        employeeEntity.setMiddleInitial(employee.getMiddleInitial());
        employeeEntity.setLastName(employee.getLastName());
        employeeEntity.setDepartment(departmentEntity);
        employeeEntity.setJobTitle(jobTitleEntity);
        employeeEntity.setIsManager(employee.getIsManager());
        employeeEntity.setSkypeName(employee.getSkypeName());
        employeeEntity.setIsActive(employee.getIsActive());

        return employeeEntity;
    }

package com.nexient.orgchart.data.entity;

import org.hibernate.validator.constraints.NotEmpty;

import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.util.Set;

@Entity
@Table(name = "employee")
public class EmployeeEntity extends BaseEntity {

    @Column(name = "first_name")
    @NotEmpty
    @Size(min = 1)
    private String firstName;

    @Column(name = "middle_initial")
    private Character middleInitial;

    @Column(name = "last_name")
    @NotEmpty
    @Size(min = 1)
    private String lastName;

    @Column(name = "email")
    @NotEmpty
    @Size(min = 1)
    private String email;

    @Column(name = "skype_name")
    @NotEmpty
    @Size(min = 1)
    private String skypeName;

    @ManyToOne
    @JoinColumn(name = "job_title_id")
    private JobTitleEntity jobTitle;

    @ManyToOne
    @JoinColumn(name = "manager_id")
    private EmployeeEntity manager;

    @ManyToOne
    @JoinColumn(name = "department_id")
    private DepartmentEntity department;

    @OneToMany(mappedBy = "manager")
    private Set<EmployeeEntity> ManagedEmployees;

    @OneToMany
    private Set<DepartmentEntity> ManagedDepartments;

    @Column(name = "is_manager")
    @NotNull
    private boolean isManager;

    ... Getters and Setters ...

package com.nexient.orgchart.data.entity;

import org.hibernate.validator.constraints.NotEmpty;

import javax.persistence.*;
import java.util.Set;

@Entity
@Table(name = "job_title")
public class JobTitleEntity extends BaseEntity {

    @Column(name = "name", unique = true)
    @NotEmpty
    private String name;

    @OneToMany
    private Set<EmployeeEntity> titleEmployees;

    ... Getters and Setters ...

package com.nexient.orgchart.data.entity;

import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.NotEmpty;

import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "department")
public class DepartmentEntity extends BaseEntity {

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "manager_id")
    private EmployeeEntity manager;

    @Column(name = "name", nullable = false, length = 50, unique = true)
    @NotNull
    @NotEmpty
    @Size(min = 1, max = 45)
    private String name;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "parent_department_id", referencedColumnName = "ID")
    private DepartmentEntity parentDepartment;

    @OneToMany(mappedBy = "parentDepartment")
    private Set<DepartmentEntity> departments = new HashSet<>(0);

    @OneToMany(mappedBy = "department")
    private Set<EmployeeEntity> employees = new HashSet<>(0);

    ... Getters and Setters ...

@ManyToOne
@JoinColumn(name = "department_id")
private DepartmentEntity department;