Java Hibernate - 无法连接到H2
问题描述 投票：1回答：1
我需要帮助。我不知道这个项目有什么问题。我无法连接到h2数据库。即使我没有持久存在任何对象，只是关闭连接，我也会收到错误。
对不起，我知道，有几次被问过，但没有一个答案适合我的情况。
我得到的错误：
org.hibernate.Version logVersion INFO：HHH000412：Hibernate Core {5.2.12.Final} 2019年3月4日11:00:24 org.hibernate.cfg.Environment信息：HHH000206：03年4月4日11:00:24 org.hibernate.Version logVersion hibernate.properties not found Mar 04,20199 11:00:24 PM org.hibernate.boot.jaxb.internal.stax.LocalXmlResourceResolver resolveEntity WARN：HHH90000012：已识别的过时hibernate名称空间http://hibernate.sourceforge.net/hibernate-configuration。请改用名称空间http://www.hibernate.org/dtd/hibernate-configuration。可以随时删除对过时的DTD / XSD命名空间的支持。 org.hibernate.annotations.common.reflection.java.JavaReflectionManager INFO：HCANN000001：Hibernate Commons Annotations {5.0.1.Final} 2010年3月4日11:00:25 org.hibernate .engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl配置WARN：HHH10001002：使用Hibernate内置连接池（不供生产使用！）org.hibernate.service.spi.ServiceException：无法创建请求的服务[org.hibernate.engine org.hibernate.service.internal.AbstractServiceRegistryImpl.createService（AbstractServiceRegistryImpl.java:271）中的org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService（AbstractServiceRegistryImpl.java:233）中的.jdbc.env.spi.JdbcEnvironment]。位于org.hibernate.boot.registry.internal.StandardServiceRegistryImpl的org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure（JdbcServicesImpl.java:51）中的hibernate.service.internal.AbstractServiceRegistryImpl.getService（AbstractServiceRegistryImpl.java:210）。 CONF igService（StandardServiceRegistryImpl.java:94）位于org.hibernate的org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService（AbstractServiceRegistryImpl.java:242）org.hibernate.service.internal.AbstractServiceRegistryImpl.getService（AbstractServiceRegistryImpl.java:210）位于org.hibernate.boot.model的org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete（MetadataBuildingProcess.java:111）中的.boot.model.process.spi.MetadataBuildingProcess.handleTypes（MetadataBuildingProcess.java:352）位于org.hibernate.boot.internal.MetadataBuilderImpl.build（MetadataBuilderImpl.java）的org.hibernate.boot.internal.MetadataBuilderImpl.build（MetadataBuilderImpl.java:418）中的.process.spi.MetadataBuildingProcess.build（MetadataBuildingProcess.java:83） ：87）org.hibernate.cfg.Configuration.buildSessionFactory（Configuration.java:691）org.hibernate.cfg.Configuration.buildSessionFactory（Configuration.java:726）orm.hibernate.employees.HibernateUtils。（HibernateUtils.java） ：13）at orm.hibernate.employees.EmployeesApp.main（EmployeesApp.java:21）中的orm.hibernate.employees.EmployeeRepository.addNewEmployee（EmployeeRepository.java:16）引起：org.hibernate.boot.registry.classloading.spi.ClassLoadingException：无法在org.hibernate.engine.ClassLoaderServiceImpl.classForName（ClassLoaderServiceImpl.java:348）的org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible中加载类[org.h2.Driver] （DriverManagerConnectionProviderImpl.java:160）org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator（DriverManagerConnectionProviderImpl.java:116）org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool（DriverManagerConnectionProviderImpl.java） ：100）在org.hibernate.boot.regist的org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure（DriverManagerConnectionProviderImpl.java:72） org.hibernate.service.internal.AbstractServiceRegistryImpl.getService（AbstractServiceRegistryImpl.java：org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService（AbstractServiceRegistryImpl.java:242）中的ry.internal.StandardServiceRegistryImpl.configureService（StandardServiceRegistryImpl.java:94） 210）org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess（JdbcEnvironmentInitiator.java:145）org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService（JdbcEnvironmentInitiator.java:66）at org位于org.hibernate.service.internal的org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService（StandardServiceRegistryImpl.java:88）的.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService（JdbcEnvironmentInitiator.java:35） .AbstractServiceRegistryImpl.createService（AbstractServiceRegistryImpl.java:259）... 16更多引起：java.lang.ClassNotFoundException：无法加载请求d class：org.hhiber org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl $ AggregatedClassLoader.findClass（ClassLoaderServiceImpl.java:336）at java.lang.ClassLoader.loadClass（ClassLoader.java:424）at java位于org.hibernate.boot.registry.classloading的java.lang.Class.forName（Class.java:348）java.lang.Class.forName0（Native Method）的.lang.ClassLoader.loadClass（ClassLoader.java:357） .internal.ClassLoaderServiceImpl.classForName（ClassLoaderServiceImpl.java:345）... 28更多
##### Initial SessionFactory creation failed.org.hibernate.service.spi.ServiceException: Unable to create请求的服务[org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]线程“main”中的异常java.lang.ExceptionInInitializerError：连接数据库错误！ orm.hibernate.employees.HibernateUtils。（HibernateUtils.java:17）orm.hibernate.employees.EmployeesApp.main上的orm.hibernate.employees.EmployeeRepository.addNewEmployee（EmployeeRepository.java:16）（EmployeesApp.java:21）
进程以退出代码1结束
pom.hml：
<?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>brudnopis.com</groupId>
<artifactId>brudnopis2</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.12.Final</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.196</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Hibernate Utils类：
public class HibernateUtils {
private static final SessionFactory sessionFactory;
static {
try {
sessionFactory = new Configuration().configure("hibernate.cfg.xml").buildSessionFactory();
} catch (Throwable ex) {
ex.printStackTrace();
System.err.println("########### Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError("Connection to database error!");
}
}
public static Session openSession() throws Exception {
Session session;
try {
session = sessionFactory.openSession();
} catch (Exception e) {
e.printStackTrace();
throw new Exception("Connection to database error!");
}
return session;
}
public static void closeSession(){
sessionFactory.close();
}
}
知识库
public class EmployeeRepository {
// Create
public static void addNewEmployee(EmployeeEntity employee){
Session session = null;
try {
session = HibernateUtils.openSession();
session.getTransaction().begin();
session.saveOrUpdate(employee);
session.getTransaction().commit();
}catch (Exception e){
e.printStackTrace();
}finally {
if (session != null && session.isOpen()) {
session.close();
}
}
}
// Read
public static List<EmployeeEntity> listAllEmployees(){
List<EmployeeEntity> listEmployees = new ArrayList<EmployeeEntity>();
Session session = null;
try {
session = HibernateUtils.openSession();
listEmployees = session.createQuery("SELECT e FROM EmployeeEntity e").getResultList();
} catch (Exception e) {
e.printStackTrace();
}finally {
if (session != null && session.isOpen()) {
session.close();
}
}
return listEmployees;
}
// Update
public static void editExistingEmployee(EmployeeEntity employee){
Session session = null;
try {
session = HibernateUtils.openSession();
session.getTransaction().begin();
session.merge(employee);
session.getTransaction().commit();
}catch (Exception e){
e.printStackTrace();
}finally{
if (session != null && session.isOpen()) {
session.close();
}
}
}
//Delete
public static void deleteEmployee(int idToDelete){
Session session = null;
try {
session = HibernateUtils.openSession();
EmployeeEntity employeeToDelete = session.find(EmployeeEntity.class, idToDelete);
session.getTransaction().begin();
session.remove(employeeToDelete);
session.getTransaction().commit();
}catch (Exception e){
e.printStackTrace();
}finally{
if (session != null && session.isOpen()) {
session.close();
}
}
}
}
实体类：
@Entity
@Table(name = "employees")
public class EmployeeEntity {
@Id
@Column(name = "id")
private int id;
@Column(name = "employee_id")
private int employeeId;
@Column(name = "first_name")
private String firstName;
@Column(name = "last_name")
private String lastName;
public EmployeeEntity(int id, int employeeId, String firstName, String lastName) {
this.id = id;
this.employeeId = employeeId;
this.firstName = firstName;
this.lastName = lastName;
}
public EmployeeEntity(){}
@Override
public String toString() {
return "EmployeeEntity{" +
"id=" + id +
", employeeId=" + employeeId +
", firstName='" + firstName + '\'' +
", lastName='" + lastName + '\'' +
'}';
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getEmployeeId() {
return employeeId;
}
public void setEmployeeId(int employeeId) {
this.employeeId = employeeId;
}
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;
}
}
主要课程：
public class EmployeesApp {
public static void main(String[] args) throws Exception {
Scanner sc = new Scanner(System.in);
System.out.println("Menu");
System.out.println("====");
System.out.println("1. Write data to database");
System.out.println("2. Read data from database");
System.out.println("3. Exit");
int userChoice = sc.nextInt();
switch(userChoice){
case 1:
EmployeeEntity employee1 = new EmployeeEntity(1,10001,"Jon", "Doe");
EmployeeRepository.addNewEmployee(employee1);
System.out.println(EmployeeRepository.listAllEmployees());
case 3:
break;
}
HibernateUtils.closeSession();
}
}
项目结构：
1个回答
投票
您的应用程序无法在运行时找到您的数据库驱动程序，因此错误Caused by: java.lang.ClassNotFoundException: Could not load requested class : org.h2.Driver。
按以下方式更改H2依赖关系：
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.196</version>
<scope>runtime</scope> <!-- Here you are saying this dependency is needed at runtime, not just at testing -->
</dependency>
拜拜！
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