java - 使用JPA和mysql启动在spring boot中创建的应用程序时出错

标签 java mysql spring jpa

我正在开发一个简单的 Spring Boot 应用程序，该应用程序可以获取数据并将其插入到我使用 MySql 工作台创建的数据库中。我不断收到以下错误。

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-09-14 11:35:14.282 ERROR 11268 --- [           main] o.s.boot.SpringApplication               : Application run failed

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.MappingException: class demo.fabric.Employee not found while looking for property: id
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1699) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:573) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:859) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
    at com.example.studentInfo.StudentOnlineInfoApplication.main(StudentOnlineInfoApplication.java:10) [classes/:na]
Caused by: org.hibernate.MappingException: class demo.fabric.Employee not found while looking for property: id
    at org.hibernate.internal.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:220) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.mapping.SimpleValue.setTypeUsingReflection(SimpleValue.java:482) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.source.internal.hbm.ModelBinder.bindSimpleEntityIdentifier(ModelBinder.java:726) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.source.internal.hbm.ModelBinder.bindEntityIdentifier(ModelBinder.java:350) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.source.internal.hbm.ModelBinder.bindRootEntity(ModelBinder.java:245) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.source.internal.hbm.ModelBinder.bindEntityHierarchy(ModelBinder.java:192) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.source.internal.hbm.HbmMetadataSourceProcessorImpl.processEntityHierarchies(HbmMetadataSourceProcessorImpl.java:144) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:218) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:265) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:861) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:888) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1758) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1695) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
    ... 16 common frames omitted
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [demo.fabric.Employee]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:348) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.util.ReflectHelper.reflectedPropertyClass(ReflectHelper.java:216) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    ... 33 common frames omitted
Caused by: java.lang.ClassNotFoundException: Could not load requested class : demo.fabric.Employee
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:336) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_161]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_161]
    at java.lang.Class.forName0(Native Method) ~[na:1.8.0_161]
    at java.lang.Class.forName(Unknown Source) ~[na:1.8.0_161]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:345) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    ... 34 common frames omitted

Below is my POM.xml file

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example.studentInfo</groupId>
<artifactId>studentOnlineInfo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>studentOnlineInfo</name>
<description>A web project which implements simple write and read to the database</description>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.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>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>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>
</project>

这是我的 application.properties 文件

spring.datasource.url=jdbc:mysql://localhost:3306/studentInfo
spring.datasource.username=root
spring.datasource.password=Christensen001
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.show-sql=true
spring.mvc.view.prefix=/WEB-INF/jsps/
spring.mvc.view.suffix=.jsp

这是我的实体类

package com.example.studentInfo.entities;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="studenData")
public class StudentInformation {
@Id
private long id;
@Column(name="sreg_num")
private String reg_num;
@Column(name="semail")
private String email;
@Column(name="sname")
private String name;
@Column(name="sage")
private int age;
@Column(name="sstate")
private String state;
@Column(name="scity")
private String city;
public long getId() {
    return id;
}
public void setId(long id) {
    this.id = id;
}
public String getReg_num() {
    return reg_num;
}
public void setReg_num(String reg_num) {
    this.reg_num = reg_num;
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}
public String getState() {
    return state;
}
public void setState(String state) {
    this.state = state;
}
public String getCity() {
    return city;
}
public void setCity(String city) {
    this.city = city;
}
public StudentInformation(long id, String reg_num, String email, String name, int age, String state, String city) {
    super();
    this.id = id;
    this.reg_num = reg_num;
    this.email = email;
    this.name = name;
    this.age = age;
    this.state = state;
    this.city = city;
}
@Override
public String toString() {
    return "StudentInformation [id=" + id + ", reg_num=" + reg_num + ", email=" + email + ", name=" + name
            + ", age=" + age + ", state=" + state + ", city=" + city + "]";
}
} </pre>

studentInfoApplication.java

package com.example.studentInfo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class StudentOnlineInfoApplication {

public static void main(String[] args) {
    SpringApplication.run(StudentOnlineInfoApplication.class, args);
}
}

如何解决这个问题？

最佳答案

更新

第 1 步:下载可能已损坏。尝试删除 ~/.m2/respository 并运行 mvn clean install

  • 如果它不起作用，那么将建议从 SPRING INITIALIZR 创建新项目具有所有必需的依赖项。

  • 如果这不起作用，则建议重新安装 IDE，因为安装/缓存它时可能会出现一些问题。

    • 当我尝试使用相同的 Spring Boot 配置时，您的实体似乎加载良好。所以看来问题是你的mysql表和实体之间的映射，所以检查你是否有id作为表中定义的主键。

    或者最好在 application.properties 中使用以下属性来首次自动创建表。稍后您可以将此属性更新为 none

    spring.jpa.hibernate.ddl-auto=create
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL57Dialect

    只是建议像这样管理主键的 ID 配置。

    @Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;

    更新

    1. 从 StudentsController.java 中删除 @Autowired

    2. 删除 tomcat-embed-core 依赖项，因为 Spring Boot 注解已嵌入它。

      <dependency>
  <groupId>org.apache.tomcat.embed</groupId>
  <artifactId>tomcat-embed-core</artifactId>
  <scope>provided</scope>
</dependency>

    3. 立即运行您的代码库。

    关于java - 使用JPA和mysql启动在spring boot中创建的应用程序时出错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52334565/

    上一篇：php - 如何检测 foreach 数据库查询中的重复项

    下一篇：php - 如何修复PHP中的“ header 已发送”错误

    相关文章：

    java - 如何在 spring-mvc 中为 REST 查询提供对象列表？

    java - p :commandbutton doing the opposite of what i require

    java - 具有共享代码的两个代号一个项目

    java - 如何使用 Apache CXF 将 web 服务客户端绑定(bind)到指定的 IP(网络接口(interface))？

    php - 我如何创建一个系统来计算上次看到的时间

    Mysql 子查询的执行

    java - 查询没有返回唯一结果: 3; nested exception is javax. persistence.NonUniqueResultException:(Spring JPA项目)

    java - SAML 元数据条目的签名信任建立失败

    Mysql - 多个连接表的总计数

    java - Spring Integration 有状态 TCP 连接

    ©2024 IT工具网  联系我们