停止Tomcat不会删除Derby db.lck

Question

停止Tomcat不会删除Derby db.lck

Kev*_*man 3 java spring tomcat derby spring-mvc

(编辑:我已经在问题中添加了一笔赏金.我找到了一个解决方法(在下面发布了一个答案),但我希望有人能够解释为什么首先需要解决方法.)

我有一个Spring webapp,它在开发过程中连接到Derby数据库.这在第一次运行webapp时工作正常,但在后续运行中,它在启动时失败,"Derby的另一个实例可能已经启动了数据库"SQLException.

我知道这是因为当我关闭Tomcat时,与Derby的连接没有被关闭,即使我希望Spring自动处理它.所以我的问题是,如何正确断开与Derby的连接？不仅在手动停止Tomcat期间,而且在热部署新的.war文件期间？

我想避免使用Derby服务器,我也使用注释而不是XML配置.这是我原来的PersistConfig类:

package com.example.spring.config;

import java.beans.PropertyVetoException;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.derby.jdbc.EmbeddedDataSource;
import org.hibernate.SessionFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
import org.springframework.jdbc.datasource.embedded.ConnectionProperties;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseConfigurer;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
import org.springframework.orm.hibernate4.HibernateExceptionTranslator;
import org.springframework.orm.hibernate4.HibernateTransactionManager;
import org.springframework.orm.hibernate4.LocalSessionFactoryBean;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@ComponentScan({"com.example.spring.dao.jpa"})
@EnableTransactionManagement // <-- enable @Transactional annotations for spring @Component and stereotypes
public class PersistConfig{


    @Bean
    public HibernateExceptionTranslator exceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    @Bean
    public LocalSessionFactoryBean localSessionFactoryBean(DataSource dataSource, JpaVendorAdapter vendorAdapter) {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource(dataSource);
        localSessionFactoryBean.setPackagesToScan("com.example.one", "com.example.two");

        Properties properties = new Properties();
        properties.putAll(vendorAdapter.getJpaPropertyMap());
        localSessionFactoryBean.setHibernateProperties(properties);

        return localSessionFactoryBean;
    }

    @Bean
    public HibernateTransactionManager hibernateTransactionManager(SessionFactory sessionFactory) {
        HibernateTransactionManager hibernateTransactionManager = new HibernateTransactionManager(sessionFactory);

        return hibernateTransactionManager;
    }

    @Configuration
    public static class DevelopmentConfig{
        @Bean
        public DataSource dataSource() throws SQLException, PropertyVetoException {



            DataSource dataSource = new SimpleDriverDataSource(new org.apache.derby.jdbc.EmbeddedDriver(), "jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB", "", "");

            System.out.println("RETURNING DATASOURCE");

            return dataSource;

        }

        @Bean
        JpaVendorAdapter vendorAdapter() {
            HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();

            vendorAdapter.setDatabase(Database.DERBY);
            vendorAdapter.setDatabasePlatform("org.hibernate.dialect.DerbyDialect");
            vendorAdapter.setGenerateDdl(true);
            vendorAdapter.setShowSql(true);

            vendorAdapter.getJpaPropertyMap().put("hibernate.hbm2ddl.auto", "update");
            vendorAdapter.getJpaPropertyMap().put("hbm2ddl.auto", "update");

            return vendorAdapter;
        }
    }
}

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我尝试使用Runtime.addShutdownHook()向整个JVM添加一个关闭钩子,我手动断开与Derby数据库的连接,但这似乎永远不会被解雇.

然后我被告知要查看EmbeddedDatabaseConfigurer接口以添加一个Spring关闭回调,我手动关闭数据库连接,这就是我提出的:

package com.example.spring.config;

import java.beans.PropertyVetoException;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.derby.jdbc.EmbeddedDataSource;
import org.hibernate.SessionFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.SimpleDriverDataSource;
import org.springframework.jdbc.datasource.embedded.ConnectionProperties;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseConfigurer;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
import org.springframework.orm.hibernate4.HibernateExceptionTranslator;
import org.springframework.orm.hibernate4.HibernateTransactionManager;
import org.springframework.orm.hibernate4.LocalSessionFactoryBean;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@ComponentScan({"com.example.spring.dao.jpa"})
@EnableTransactionManagement // <-- enable @Transactional annotations for spring @Component and stereotypes
public class PersistConfig implements EmbeddedDatabaseConfigurer {


    @Bean
    public HibernateExceptionTranslator exceptionTranslator() {
        return new HibernateExceptionTranslator();
    }

    @Bean
    public LocalSessionFactoryBean localSessionFactoryBean(DataSource dataSource, JpaVendorAdapter vendorAdapter) {
        LocalSessionFactoryBean localSessionFactoryBean = new LocalSessionFactoryBean();
        localSessionFactoryBean.setDataSource(dataSource);
        localSessionFactoryBean.setPackagesToScan("com.example.one", "com.example.two");

        Properties properties = new Properties();
        properties.putAll(vendorAdapter.getJpaPropertyMap());
        localSessionFactoryBean.setHibernateProperties(properties);

        return localSessionFactoryBean;
    }

    @Bean
    public HibernateTransactionManager hibernateTransactionManager(SessionFactory sessionFactory) {
        HibernateTransactionManager hibernateTransactionManager = new HibernateTransactionManager(sessionFactory);

        return hibernateTransactionManager;
    }

    @Configuration
    public static class DevelopmentConfig{
        @Bean
        public DataSource dataSource() throws SQLException, PropertyVetoException {



            DataSource dataSource = new SimpleDriverDataSource(new org.apache.derby.jdbc.EmbeddedDriver(), "jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB", "", "");

            System.out.println("RETURNING DATASOURCE");

            return dataSource;

        }

        @Bean
        JpaVendorAdapter vendorAdapter() {
            HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();

            vendorAdapter.setDatabase(Database.DERBY);
            vendorAdapter.setDatabasePlatform("org.hibernate.dialect.DerbyDialect");
            vendorAdapter.setGenerateDdl(true);
            vendorAdapter.setShowSql(true);

            vendorAdapter.getJpaPropertyMap().put("hibernate.hbm2ddl.auto", "update");
            vendorAdapter.getJpaPropertyMap().put("hbm2ddl.auto", "update");

            return vendorAdapter;
        }       
    }

    @Override
    public void configureConnectionProperties(ConnectionProperties properties, String databaseName) {

        System.out.println("CONFIGURE");

        properties.setDriverClass(org.apache.derby.jdbc.EmbeddedDriver.class);
        properties.setUrl("jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB");
    }

    @Override
    public void shutdown(DataSource ds, String databaseName) {

        System.out.println("SHUTTING DOWN");

        try {
            DriverManager.getConnection("jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB;shutdown=true");
        } 
        catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

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但是,似乎都没有调用configureConnectionProperties()函数和shutdown()函数.我显然不知道我在做什么,所以任何指针都非常感激.

Answer 1

Ser*_*sta 7

编辑:添加重新启动嵌入式Derby数据库的精度和一个可能更简单的解决方案.

我可以至少部分地重现问题,理解它并修复它.但我不能说为什么BoneCP工作正常.我只是注意到,如果我在关闭tomcat并重新启动它之间等待足够多,那就可以了.我想BoneCP不会立即访问数据库,并等到第一次真正的连接.

首先是问题:当使用Derby作为嵌入式数据库时,数据库在第一次连接时启动,但必须明确地关闭它.如果不是,db.lock则不删除该文件,并且进一步的应用程序可能会在再次启动数据库时遇到问题.在tomcat中或者(默认情况下)在spring中没有任何东西可以自动关闭这样的数据库.

接下来,为什么你的尝试使用EmbeddedDatabaseConfigurer不起作用:EmbeddedDatabaseConfigurer不是魔术标记并且在类中继承它不足以让spring自动使用它.它只是一个必须由配置器实现以允许EmbeddedDatabaseFactory使用它的接口.

最后解决了.您不应该使用SimpleDriverDataSource从嵌入式Derby数据库获取连接,而是使用EmbeddedDatabaseFactory.Spring默认情况下知道Derby嵌入式数据库,你可以通过简单地设置类型来配置工厂......但是这只适用于内存数据库并且你有一个文件数据库!本来就太简单了......你必须向工厂注入一个配置器才能让一切正常.

现在代码(从你的第一个版本开始):

@Configuration
public static class DevelopmentConfig{
    EmbeddedDatabaseFactory dsFactory;

    public DevelopmentConfig() {
        EmbeddedDatabaseConfigurer configurer = new EmbeddedDatabaseConfigurer() {
            @Override
            public void configureConnectionProperties(ConnectionProperties properties, String databaseName) {
                System.out.println("CONFIGURE");

                properties.setDriverClass(org.apache.derby.jdbc.EmbeddedDriver.class);
                properties.setUrl("jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB");
            }

            @Override
            public void shutdown(DataSource dataSource, String databaseName) {
                final String SHUTDOWN_CODE = "XJ015";
                System.out.println("SHUTTING DOWN");

                try {
                    DriverManager.getConnection("jdbc:derby:;shutdown=true");
                } catch (SQLException e) {
                    // Derby 10.9.1.0 shutdown raises a SQLException with code "XJ015"
                    if (!SHUTDOWN_CODE.equals(e.getSQLState())) {
                        e.printStackTrace();;
                    }
                }
            }
        };
        dsFactory = new EmbeddedDatabaseFactory();
        dsFactory.setDatabaseConfigurer(configurer);
    }

    @Bean
    public DataSource dataSource() throws SQLException, PropertyVetoException {

        System.out.println("RETURNING DATASOURCE");

        return dsFactory.getDatabase();
    }

    // remaining of code unchanged

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这样,我可以热重新加载战争,当tomcat关闭时,db.lock通常会被破坏.

编辑:如果出现问题,Derby文档建议在关闭后添加以下命令以重新启动数据库:Class.forName("org.apache.derby.jdbc.EmbeddedDriver").newInstance();.它可能是该configureConnectionProperties方法的最后一条指令.

但实际上,解决方案可能更简单.什么真正需要被添加到您的配置是嵌入式驱动程序(并最终重新启动)的正常关机.所以一个简单的PreDestroy(和eventualy` @ PostConstruct)注释方法就足够了:

@Configuration
public static class DevelopmentConfig{

    @PreDestroy
    public void shutdown() {
        final String SHUTDOWN_CODE = "XJ015";
        System.out.println("SHUTTING DOWN");

        try {
            DriverManager.getConnection("jdbc:derby:;shutdown=true");
        } catch (SQLException e) {
            // Derby 10.9.1.0 shutdown raises a SQLException with code "XJ015"
            if (!SHUTDOWN_CODE.equals(e.getSQLState())) {
                e.printStackTrace();
            }
        }
    }

    /* if needed ...
    @PostConstruct
    public void init() throws InstantiationException, IllegalAccessException, ClassNotFoundException {
        Class.forName("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
    }
    */
    @Bean
    public DataSource dataSource() throws SQLException, PropertyVetoException {

        DataSource dataSource = new SimpleDriverDataSource(new org.apache.derby.jdbc.EmbeddedDriver(), "jdbc:derby:C:\\Users\\Kevin\\Desktop\\DerbyDB", "", "");

        System.out.println("RETURNING DATASOURCE");

        return dataSource;

    }

    // remaining of code unchanged

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此变体的主要兴趣在于您可以选择数据源,从SimpleDriverDataSource实际池到实际池.

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