Hibernate：在Servlet中运行时找不到合适的驱动程序

时间：2015-10-06 05:55:32

标签： java hibernate servlets

所以，现在我正在做我的第一个webapp。这在网络方面比较粗糙。一些servlet和JSP页面，加上Hibernate和数据库访问。没有框架，MVC，任何这些（是的，这一切都非常重要，但这只是我在开始处理更大的事情之前对Servlets的理解程度的快速测试）。

无论如何，我遇到了Hibernate的问题。奇怪的是，它必须与Hibernate与servlet / server的交互有关。

让我解释一下：我有一个测试类（字面意思是一个名为Test的类），我只是用来测试我的ORM映射注释。它完美地运作。像110％完美。建立连接，操作数据库等等。这是它的代码，再次只是一个简单的测试（ClassesServiceImpl是一个内部有Hibernate SessionFactory的服务）：

public static void main(String[] args) {
    ClassesServiceImpl service = (ClassesServiceImpl) ClassesServiceImpl.getInstance();

    Student student = service.createStudent("Bob", "Saget", LocalDate.of(1988,10,26), 11);
    Course math = new Course("Math", "Anderson", 5);
    student.addCourse(math);
    service.saveStudent(student);

    service.close();
}

我刚粘贴的代码有效。没问题，我可以在运行之后直接进入MySQL，并且有更改。

问题是，当我尝试在Servlet中做同样的事情时，我得到一个例外。这是代码：

private ClassesService service;

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    List<Student> studentList = service.getAllStudents();
    req.setAttribute("studentList", studentList);
    req.getRequestDispatcher("/studentlist.jsp").forward(req, resp);
}

@Override
public void init(ServletConfig config) throws ServletException {
    service = ClassesServiceImpl.getInstance();
}

当我运行该Servlet时，我得到一个Hibernate ServiceException：无法创建请求的服务[org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]。堆栈跟踪有一系列原因，它们引用调用DriverManager＃getConnection的错误，最终以SQLException结束：找不到jdbc：mysql：// localhost：3306 / classes的可用驱动程序。

我正在粘贴下面的完整堆栈跟踪。我只是不明白为什么会这样。当我不在服务器上使用它时它完美地工作，但当我在服务器上使用它时，会发生这种情况。

帮助将不胜感激。感谢。

org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:244)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:208)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
io.craigmiller160.classes.servlet.StudentListServlet.doGet(StudentListServlet.java:29)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
root cause

org.hibernate.exception.JDBCConnectionException: Error calling DriverManager#getConnection
org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:115)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:101)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionCreator.makeConnection(DriverManagerConnectionCreator.java:37)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:89)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:234)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:208)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
io.craigmiller160.classes.servlet.StudentListServlet.doGet(StudentListServlet.java:29)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
root cause

java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/classes
java.sql.DriverManager.getConnection(DriverManager.java:689)
java.sql.DriverManager.getConnection(DriverManager.java:208)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionCreator.makeConnection(DriverManagerConnectionCreator.java:34)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:89)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:234)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:208)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
io.craigmiller160.classes.servlet.StudentListServlet.doGet(StudentListServlet.java:29)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

编辑：

有些人提到驱动程序需要在我的类路径中。嗯，确实如此。记住我所说的：当我没有在servlet中运行它时，它可以工作。我上面粘贴的测试代码工作正常。只有当我在servlet中运行它时才会发生问题。 

<!-- MySQL ConnectorJ -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.36</version>
</dependency>

1 个答案:

答案 0 :(得分：1)

  

找不到jdbc：mysql：// localhost：3306 / classes

的sutiable驱动程序

此错误只是说明在Web应用程序中执行时，MySQL-JDBC驱动程序不在您的类路径中。

  • 在WEB-INF / lib目录中存在确定的jar文件并添加到 类路径 - Follow this

您在Simple Java Program中没有遇到任何问题，因为已经在Windows / Linux OS类路径中添加了Jar文件 - Check this

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