无法打开请求类型的Javax.Sql.Datasource - Spring java配置。

Question

我很难让hibernate和Spring一起工作。我得到了以下例外：

org.springframework.beans.factory.BeanCreationException:错误创建名为“txManager”的bean : Bean通过工厂方法实例化失败；嵌套异常是org.springframework.beans.BeanInstantiationException:未能实例化org.springframework.orm.hibernate5.HibernateTransactionManager:工厂方法'txManager‘抛出的异常；嵌套异常是org.hibernate.service.UnknownUnwrapTypeException:不能打开请求的javax.sql.DataSource类型

我能找到的唯一相似之处是缺少c3p0连接池，但是我的gradle构建文件中有c3p0的依赖项，属性被传递到hibernates配置中。

有人能建议我如何修复这个配置吗？

谢谢

import java.util.Properties;

import org.apache.tomcat.jdbc.pool.DataSource;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBuilder; 
import org.springframework.transaction.annotation.EnableTransactionManagement;

@EnableTransactionManagement
@SpringBootApplication
public class MegLabApplication
{

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

@Value("${spring.datasource.driverClassName}")
private String databaseDriverClassName;

@Value("${spring.datasource.url}")
private String datasourceUrl;

@Value("${spring.datasource.username}")
private String databaseUsername;

@Value("${spring.datasource.password}")
private String databasePassword;

@Bean
public SessionFactory sessionFactory()
{
    Configuration configuration = new Configuration();
    configuration.setProperties(getHibernateProperties());

    ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
            .applySettings(configuration.getProperties()).build();

    LocalSessionFactoryBuilder builder = new LocalSessionFactoryBuilder(dataSource());

    builder.scanPackages("com.xxx.models");

    return builder.buildSessionFactory(serviceRegistry);
}

private Properties getHibernateProperties()
{
    Properties prop = new Properties();
    prop.put("hibernate.connection.pool_size", "10");

    prop.put("hibernate.c3p0.min_size", "5");
    prop.put("hibernate.c3p0.max_size", "20");
    prop.put("hibernate.c3p0.timeout", "300");
    prop.put("hibernate.c3p0.max_statements", "50");
    prop.put("hibernate.c3p0.idle_test_period", "60");

    prop.put("hibernate.format_sql", "true");
    prop.put("hibernate.show_sql", "true");
    prop.put("hibernate.dialect", "org.hibernate.dialect.MySQL5InnoDBDialect");
    prop.put("hibernate.hbm2ddl.auto", "update");
    return prop;
}

@Bean(name = "dataSource")
public DataSource dataSource()
{
    DataSource ds = new DataSource();
    ds.setDriverClassName(databaseDriverClassName);
    ds.setUrl(datasourceUrl);
    ds.setUsername(databaseUsername);
    ds.setPassword(databasePassword);
    return ds;
}

@Bean
public HibernateTransactionManager txManager()
{
    return new HibernateTransactionManager(sessionFactory());
}
}

Answer 1

好吧，我终于把这一切都做好了.

Spring引导使用hibernate 4.3.11。我最初配置中的HibernateTransactionManager类使用的是Hibernate5，因此我将类版本更改为4，我的C3P0依赖项也是版本5，因此我将其降级为4。

我还必须将连接细节添加到hibernate属性中，并通过指定类显式地告诉它使用C3P0连接提供程序。

prop.put("hibernate.connection.provider_class", "org.hibernate.c3p0.internal.C3P0ConnectionProvider")

希望这能帮助任何在Spring支持Hibernate 5之前遇到这种情况的人。