考虑在配置中定义类型 'javax.persistence.EntityManager' 的 Bean

Question

我是春季的初学者。所以现在我开始学习springboot并构建这个简单的项目，但当我运行它时，我遇到了这个错误"sagala.rest.boot.remade.dao.EmployeeDaoImpl中的字段entityManager需要一个类型为"javax.persistence.entityManager"的bean，但找不到该bean。".

这是我的控制器类

package sagala.rest.boot.remade.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import sagala.rest.boot.remade.entity.Employee;
import sagala.rest.boot.remade.service.EmployeeService;

@RestController
@RequestMapping("/api")
public class MainController {
@Autowired
private EmployeeService employeeService;
@GetMapping("/employees")
public List<Employee> findAll() {
return employeeService.findAll();
}
}

这是服务类

package sagala.rest.boot.remade.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import sagala.rest.boot.remade.dao.EmployeeDao;
import sagala.rest.boot.remade.entity.Employee;
@Service
public class EmployeeServiceImpl implements EmployeeService {
@Autowired
private EmployeeDao employeeDao;
@Override
@Transactional
public List<Employee> findAll() {
return employeeDao.findAll();
}
}

这是DAO类

package sagala.rest.boot.remade.dao;
import java.util.List;
import javax.persistence.EntityManager;
import org.hibernate.Session;
import org.hibernate.query.Query;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import sagala.rest.boot.remade.entity.Employee;
@Repository
public class EmployeeDaoImpl implements EmployeeDao {
@Autowired
private EntityManager entityManager;
@Override
public List<Employee> findAll() {
Session session =entityManager.unwrap(Session.class);
Query<Employee> query =session.createQuery("from Employee", Employee.class);
List<Employee> employees =query.getResultList();
return employees;
}
}

这是实体类

package sagala.rest.boot.remade.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="employee")
public class Employee {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="id")
private int id;
@Column(name="first_name")
private String firstName;
@Column(name="last_name")
private String lastName;
@Column(name="email")
private String email;
public Employee() {
}
public Employee(String firstName, String lastName, String email) {
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}

这是POM文件

<?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>2.2.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>sagala</groupId>
<artifactId>rest.boot.remade</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>rest.boot.remade</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<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>
<optional>true</optional>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

以下是应用程序属性

spring.datasource.url=jdbc:mysql://localhost:3306/employee_directory?useSSL=false&serverTimezone=UTCspring.datasource.username=弹簧*******spring.datasource.password=spring*******

如果有人能帮我的话。谢谢

Answer 1

我将spring-boot版本从2.2.6更改为2.1.13，一切都很好。在较新的春季启动版本中，javax.persistence.EntityManager似乎已损坏。尽管多次删除了repo，但在尝试将JpaRepository接口扩展为另一个可选的dao实现时，我仍然找不到它。