未找到 c3p0 hsqldb 驱动程序类

Posted 2023-04-18

【中文标题】未找到 c3p0 hsqldb 驱动程序类

【英文标题】：c3p0 hsqldb driver class not found

【发布时间】：2019-05-02 17:43:34

【问题描述】：

我正在尝试使用 spring hibernate 和 maven 创建一个简单的 Web 服务。当我尝试执行项目时，c3p0 找不到驱动程序类。我正在尝试以独立非嵌入式模式连接到 HSQLDB。

我得到的错误是：

May 02, 2019 12:17:08 PM com.mchange.v2.c3p0.DriverManagerDataSource 
WARNING: Could not load driverClass org.hsqldb.jdbc.JDBCDriver
java.lang.ClassNotFoundException: org.hsqldb.jdbc.JDBCDriver
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1291)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at com.mchange.v2.c3p0.DriverManagerDataSource.ensureDriverLoaded(DriverManagerDataSource.java:143)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:173)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)

我验证了 JAR 文件在那里，我创建了另一个只有 hibernate 和 c3p0 的项目，一切正常。当我包含 spring 时，问题就出现了。

这是我的 POM 文件

<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.luv2code.springdemo</groupId>
    <artifactId>spring-crm-rest</artifactId>
    <version>1.0.0</version>
    <packaging>war</packaging>

    <properties>
        <springframework.version>5.0.6.RELEASE</springframework.version>
        <hibernate.version>5.4.1.Final</hibernate.version>
        <mysql.connector.version>5.1.45</mysql.connector.version>
        <c3po.version>0.9.5.2</c3po.version>

        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>

        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>$springframework.version</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>$springframework.version</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>$springframework.version</version>
        </dependency>

        <!-- Add Jackson for JSON converters -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.5</version>
        </dependency>

        <!-- Hibernate -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>$hibernate.version</version>
        </dependency>

        <!-- MySQL -->
        <!-- <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> 
            <version>$mysql.connector.version</version> </dependency> -->

        <!-- https://mvnrepository.com/artifact/org.hsqldb/hsqldb -->
        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <version>2.4.1</version>
            <scope>test</scope>
        </dependency>

        <!-- C3PO -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>$c3po.version</version>
        </dependency>

        <!-- Servlet+JSP+JSTL -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.1</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>


        <!-- to compensate for java 9 not including jaxb -->
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.0</version>
        </dependency>

    </dependencies>

    <build>

        <finalName>spring-crm-rest</finalName>

        <plugins>

            <!-- Builds a Web Application Archive (WAR) file from the project output 
                and its dependencies. -->
            <plugin>
                <!-- Add Maven coordinates (GAV) for: maven-war-plugin -->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.2.0</version>
            </plugin>

        </plugins>
    </build>
</project>

这是我的配置类

@Configuration
@EnableWebMvc
@EnableTransactionManagement
@ComponentScan("com.luv2code.springdemo")
@PropertySource( "classpath:persistence-mysql.properties" )
public class DemoAppConfig implements WebMvcConfigurer 

    @Autowired
    private Environment env;

    private Logger logger = Logger.getLogger(getClass().getName());

    // define a bean for ViewResolver

    @Bean
    public DataSource myDataSource() 

        // create connection pool
        ComboPooledDataSource myDataSource = new ComboPooledDataSource();

        // set the jdbc driver
        try 
            myDataSource.setDriverClass(env.getProperty("jdbc.driver"));        
        
        catch (PropertyVetoException exc) 
            throw new RuntimeException(exc);
        

        // for sanity's sake, let's log url and user ... just to make sure we are reading the data
        logger.info("jdbc.url=" + env.getProperty("jdbc.url"));
        logger.info("jdbc.user=" + env.getProperty("jdbc.user"));

        // set database connection props
        myDataSource.setJdbcUrl(env.getProperty("jdbc.url"));
        myDataSource.setUser(env.getProperty("jdbc.user"));
        myDataSource.setPassword(env.getProperty("jdbc.password"));

        // set connection pool props
        myDataSource.setInitialPoolSize(getIntProperty("connection.pool.initialPoolSize"));
        myDataSource.setMinPoolSize(getIntProperty("connection.pool.minPoolSize"));
        myDataSource.setMaxPoolSize(getIntProperty("connection.pool.maxPoolSize"));     
        myDataSource.setMaxIdleTime(getIntProperty("connection.pool.maxIdleTime"));

        return myDataSource;
    

    private Properties getHibernateProperties() 

        // set hibernate properties
        Properties props = new Properties();

        props.setProperty("hibernate.dialect", env.getProperty("hibernate.dialect"));
        props.setProperty("hibernate.show_sql", env.getProperty("hibernate.show_sql"));

        return props;               
    


    // need a helper method 
    // read environment property and convert to int

    private int getIntProperty(String propName) 

        String propVal = env.getProperty(propName);

        // now convert to int
        int intPropVal = Integer.parseInt(propVal);

        return intPropVal;
       

    @Bean
    public LocalSessionFactoryBean sessionFactory()

        // create session factorys
        LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();

        // set the properties
        sessionFactory.setDataSource(myDataSource());
        sessionFactory.setPackagesToScan(env.getProperty("hibernate.packagesToScan"));
        sessionFactory.setHibernateProperties(getHibernateProperties());

        return sessionFactory;
    

    @Bean
    @Autowired
    public HibernateTransactionManager transactionManager(SessionFactory sessionFactory) 

        // setup transaction manager based on session factory
        HibernateTransactionManager txManager = new HibernateTransactionManager();
        txManager.setSessionFactory(sessionFactory);

        return txManager;
       

这是我的属性文件。

#
# JDBC connection properties
#
jdbc.driver=org.hsqldb.jdbc.JDBCDriver
jdbc.url=jdbc:hsqldb:hsql://localhost/testdb
jdbc.user=SA
jdbc.password=

#
# Connection pool properties
#
connection.pool.initialPoolSize=5
connection.pool.minPoolSize=5
connection.pool.maxPoolSize=20
connection.pool.maxIdleTime=3000

#
# Hibernate properties
#
hibernate.dialect=org.hibernate.dialect.HSQLDialect
hibernate.show_sql=true
hibernate.packagesToScan=com.luv2code.springdemo.entity

【问题讨论】：

从您的 HSQLDB 依赖项中删除 <scope>test</scope>。使用范围测试，您只能在测试中使用它，而不能在普通代码中使用。另见What is <scope> under <dependency> in pom.xml for?

感谢您的快速响应，这就是答案。您可以转到答案以便我标记它吗？

复制了我的评论作为答案。

【参考方案1】：

从您的 HSQLDB 依赖项中删除 <scope>test</scope>。使用范围测试，您只能在测试中使用它，而不能在普通代码中使用。另见What is <scope> under <dependency> in pom.xml for?

【参考方案2】：

您的 HSQLDB 依赖在“测试”范围内，因此在应用程序运行时不会被带走。更改测试变为编译