SpringBoot：Error creating bean with name 'entityManagerFactory' defined in class path resource

最近在学习SpringBoot，在学习通过SpringBoot连接mysql数据库时，报出这样的错误：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: No identifier specified for entity: com...

这个错误一度让我崩溃，各种Google后还是未能解决，我知道这又是一个非常规错误。但是在不断尝试下，终于找到问题所在。先看下源码：

package com.demo;

import org.springframework.data.annotation.Id;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import java.io.Serializable;

@Entity
public class Girl implements Serializable {

    @Id
    @GeneratedValue
    private Integer id;

    @Column
    private String cupSize;

    private Integer age;

    public Girl() {
    }

    public Girl(Integer id,  String cupSize, Integer age) {
        this.id = id;
        this.cupSize = cupSize;
        this.age = age;
    }

    /*
     *此处省略部分代码
     */
}

咋一看没问题，其实问题出在导入的包上。这里用到了@Id的注解，但是导入的包不应该是：

import org.springframework.data.annotation.Id;

而应该用：

import javax.persistence.Id;

所以，完整正确的代码如下：

package com.yangchen;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import java.io.Serializable;
import javax.persistence.Id;

@Entity
public class Girl implements Serializable {

    @Id
    @GeneratedValue
    private Integer id;

    @Column
    private String cupSize;

    private Integer age;

    public Girl() {
    }

    public Girl(Integer id,  String cupSize, Integer age) {
        this.id = id;
        this.cupSize = cupSize;
        this.age = age;
    }

    public Integer getId() {
        return id;
    }

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

    public String getCupSize() {
        return cupSize;
    }

    public void setCupSize(String cupSize) {
        this.cupSize = cupSize;
    }

    public Integer getAge() {
        return age;
    }

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

最后在附上application.properties和pom.xml文件的配置代码：

yaml格式的application代码：

spring:
  profiles:
    active: dev
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/girl?useSSL=false
    username: 你的数据库用户名
    password: 数据库密码
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true



properties类型的application代码：

spring.datasource.url=jdbc:mysql://localhost:3306/girl?characterEncoding=utf8&useSSL=true
spring.datasource.username=数据库用户名
spring.datasource.password=数据库密码
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.properties.hibernate.hbm2ddl.auto=update
spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.show-sql=true

pom.xml中的dependcies代码：


		
			org.springframework.boot
			spring-boot-starter-web
		

		
			org.springframework.boot
			spring-boot-starter-test
			test
		

		
			mysql
			mysql-connector-java
		
		
			org.springframework.boot
			spring-boot-starter-data-jpa
		

		
			junit
			junit
			4.12
		
		
			org.springframework.boot
			spring-boot-test
			RELEASE
		
		
			org.springframework
			spring-test
			4.3.12.RELEASE