我也遇到了类似的问题，但除此之外，每当我在运行Tomcat服务器的情况下修改/保存JSP页面时，我都会得到一个Java堆空间错误，因此上下文没有完全充电。

我的版本是Apache Tomcat 6.0.29和JDK 6u12。

根据URL http://wiki.apache.org/tomcat/MemoryLeakProtection的参考部分的建议，将JDK升级到6u21解决了Java堆空间问题(上下文现在重新加载OK)，尽管仍然出现JDBC驱动程序错误。

我将补充一些我在Spring论坛上发现的东西。如果您将JDBC驱动程序jar移到tomcat lib文件夹，而不是与webapp一起部署它，则警告似乎消失了。我可以确定这对我很有效

http://forum.springsource.org/showthread.php?87335-Failure-to-unregister-the-MySQL-JDBC-Driver&p=334883#post334883

针对每个应用部署的解决方案

这是一个侦听器，我写来解决这个问题:它自动检测驱动程序是否已经注册自己，并采取相应的行动

重要的是:它只能在驱动程序jar部署在WEB-INF/lib中使用，而不是像许多人建议的那样部署在Tomcat /lib中，这样每个应用程序都可以处理自己的驱动程序并在未受影响的Tomcat上运行。恕我直言，这才是应该的方式。

只需在web.xml中配置侦听器，然后再执行其他操作即可。

在web.xml顶部添加:

<listener>
    <listener-class>utils.db.OjdbcDriverRegistrationListener</listener-class>    
</listener>

保存为utils/db/OjdbcDriverRegistrationListener.java:

package utils.db;

import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Enumeration;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import oracle.jdbc.OracleDriver;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Registers and unregisters the Oracle JDBC driver.
 * 
 * Use only when the ojdbc jar is deployed inside the webapp (not as an
 * appserver lib)
 */
public class OjdbcDriverRegistrationListener implements ServletContextListener {

    private static final Logger LOG = LoggerFactory
            .getLogger(OjdbcDriverRegistrationListener.class);

    private Driver driver = null;

    /**
     * Registers the Oracle JDBC driver
     */
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        this.driver = new OracleDriver(); // load and instantiate the class
        boolean skipRegistration = false;
        Enumeration<Driver> drivers = DriverManager.getDrivers();
        while (drivers.hasMoreElements()) {
            Driver driver = drivers.nextElement();
            if (driver instanceof OracleDriver) {
                OracleDriver alreadyRegistered = (OracleDriver) driver;
                if (alreadyRegistered.getClass() == this.driver.getClass()) {
                    // same class in the VM already registered itself
                    skipRegistration = true;
                    this.driver = alreadyRegistered;
                    break;
                }
            }
        }

        try {
            if (!skipRegistration) {
                DriverManager.registerDriver(driver);
            } else {
                LOG.debug("driver was registered automatically");
            }
            LOG.info(String.format("registered jdbc driver: %s v%d.%d", driver,
                    driver.getMajorVersion(), driver.getMinorVersion()));
        } catch (SQLException e) {
            LOG.error(
                    "Error registering oracle driver: " + 
                            "database connectivity might be unavailable!",
                    e);
            throw new RuntimeException(e);
        }
    }

    /**
     * Deregisters JDBC driver
     * 
     * Prevents Tomcat 7 from complaining about memory leaks.
     */
    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        if (this.driver != null) {
            try {
                DriverManager.deregisterDriver(driver);
                LOG.info(String.format("deregistering jdbc driver: %s", driver));
            } catch (SQLException e) {
                LOG.warn(
                        String.format("Error deregistering driver %s", driver),
                        e);
            }
            this.driver = null;
        } else {
            LOG.warn("No driver to deregister");
        }

    }

}

我在AWS上部署Grails应用程序时遇到过这个问题。这是JDBC默认驱动程序的问题。H2驱动。 正如你在数据源中看到的那样。配置文件夹中的Groovy。如下图所示:

dataSource {
    pooled = true
    jmxExport = true
    driverClassName = "org.h2.Driver"   // make this one comment
    username = "sa"
    password = ""
}

注释那些提到org.h2的行。数据源中的驱动程序。Groovy文件，如果您没有使用该数据库。 否则，您必须下载数据库jar文件。

谢谢。

我经常看到这个问题。是的，Tomcat 7会自动注销它，但这真的能控制你的代码吗?这是一个好的编码实践吗?当然，您希望知道您已经准备好了关闭所有对象、关闭数据库连接池线程和消除所有警告所需的所有正确代码。我当然喜欢。

我就是这么做的。

步骤1:注册监听器

web . xml

<listener>
    <listener-class>com.mysite.MySpecialListener</listener-class>
</listener>

步骤2:实现监听器

com.mysite.MySpecialListener.java

public class MySpecialListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        // On Application Startup, please…

        // Usually I'll make a singleton in here, set up my pool, etc.
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        // On Application Shutdown, please…

        // 1. Go fetch that DataSource
        Context initContext = new InitialContext();
        Context envContext  = (Context)initContext.lookup("java:/comp/env");
        DataSource datasource = (DataSource)envContext.lookup("jdbc/database");

        // 2. Deregister Driver
        try {
            java.sql.Driver mySqlDriver = DriverManager.getDriver("jdbc:mysql://localhost:3306/");
            DriverManager.deregisterDriver(mySqlDriver);
        } catch (SQLException ex) {
            logger.info("Could not deregister driver:".concat(ex.getMessage()));
        } 

        // 3. For added safety, remove the reference to dataSource for GC to enjoy.
        dataSource = null;
    }

}

请随意评论和/或添加…

从版本6.0.24开始，Tomcat附带了内存泄漏检测特性，当web应用程序的/WEB-INF/lib中有JDBC 4.0兼容的驱动程序时，该驱动程序会在web应用程序启动期间使用ServiceLoader API自动注册自己，但在web应用程序关闭期间不会自动注销自己，这会导致此类警告消息。此消息完全是非正式的，Tomcat已经采取了相应的内存泄漏预防操作。

你能做什么?

Ignore those warnings. Tomcat is doing its job right. The actual bug is in someone else's code (the JDBC driver in question), not in yours. Be happy that Tomcat did its job properly and wait until the JDBC driver vendor get it fixed so that you can upgrade the driver. On the other hand, you aren't supposed to drop a JDBC driver in webapp's /WEB-INF/lib, but only in server's /lib. If you still keep it in webapp's /WEB-INF/lib, then you should manually register and deregister it using a ServletContextListener. Downgrade to Tomcat 6.0.23 or older so that you will not be bothered with those warnings. But it will silently keep leaking memory. Not sure if that's good to know after all. Those kind of memory leaks are one of the major causes behind OutOfMemoryError issues during Tomcat hotdeployments. Move the JDBC driver to Tomcat's /lib folder and have a connection pooled datasource to manage the driver. Note that Tomcat's builtin DBCP does not deregister drivers properly on close. See also bug DBCP-322 which is closed as WONTFIX. You would rather like to replace DBCP by another connection pool which is doing its job better then DBCP. For example HikariCP or perhaps Tomcat JDBC Pool.