java - SAP JCo 连接器在 GlassFish v2.1 中永久加载(无法卸载)

Question

我在使用 GlassFish 和 SAP JCo 连接器 (sapjco3.jar) 时遇到问题。

我在 J2EE 应用程序 (jwm.ear) 启动时加载它，并在第一次需要连接到 SAP 时将其包装在单例中进行初始化。

问题是这个 jar 始终在内存中保持初始化状态，如果我需要更改单个参数，我需要重新启动 glassfish 来卸载初始化的连接。停止或取消部署应用程序不会卸载 sapjco.jar，并且应用程序的进一步重新部署永远不会获得新的连接参数，第一次初始化将保留到 GlassFish 重新启动。

有人知道如何卸载或重新初始化这个库吗？最好即使不重新部署应用程序，第一次激活应用程序时，我都会有对 jcoProvider 的引用，下一次激活会获得对 jcoProvider 的空引用，但 jcoProvider 会继续在内存中使用初始值进行实例化。

问候!

注释:GlassFish在Windows 2008服务器中是2.1版本，jdk是1.6.0.14sapjco3.jar 和 sapjco3.dll 复制到\domains\domain1\lib\ext 并且是 SAP java 连接器的版本 3。

单例获取 SAP 连接:

package es.grupotec.ejb.SAP;import com.sap.conn.jco.JCoDestination;import com.sap.conn.jco.JCoDestinationManager;import com.sap.conn.jco.JCoException;import com.sap.conn.jco.ext.DestinationDataProvider;import com.sap.conn.jco.ext.Environment;import es.grupotec.ejb.util.ConexionSAPException;import java.util.Properties;public final class SAP {    private static String SAP_SERVER = "JWM";    private static SAP instance = null;    private static JCOProvider jcoProvider = null;    private SAP() {      // Exists only to defeat instantiation.    }    // Get SAP connection    public static synchronized JCoDestination getDestination() throws ConexionSAPException {        JCoDestination jcoDestination = null;            if (Environment.isDestinationDataProviderRegistered()) {                try {                    jcoDestination = JCoDestinationManager.getDestination(SAP_SERVER);                    return jcoDestination;                } catch (JCoException ex) {                    throw new ConexionSAPException(ex.getMessage());                }            }        // Create new connection        if(jcoProvider == null) init();        // Get connection        try {            jcoDestination = JCoDestinationManager.getDestination(SAP_SERVER);            return jcoDestination;                    } catch (JCoException ex) {                    throw new ConexionSAPException(ex.getMessage());        }    }    // Initialize connection to SAP    public static synchronized void init() throws ConexionSAPException {        SAPVO sap = new SAPVO();        Properties properties = new Properties();        if(jcoProvider == null) {            // Get SAP config from database            try {                sap = SAPDAO.getSAPConfig();            } catch (Exception ex) {                throw new ConexionSAPException(ex.getMessage());            }             // Create connection object            jcoProvider = new JCOProvider();        }        properties.setProperty(DestinationDataProvider.JCO_ASHOST,        sap.getJCO_ASHOST());        properties.setProperty(DestinationDataProvider.JCO_SYSNR,         sap.getJCO_SYSNR());        properties.setProperty(DestinationDataProvider.JCO_CLIENT,        sap.getJCO_CLIENT());        properties.setProperty(DestinationDataProvider.JCO_USER,          sap.getJCO_USER());        properties.setProperty(DestinationDataProvider.JCO_PASSWD,        sap.getJCO_PASSWD());        properties.setProperty(DestinationDataProvider.JCO_LANG,          sap.getJCO_LANG());        try {            jcoProvider.changePropertiesForABAP_AS(properties);        } catch (Exception e) {            throw new ConexionSAPException(e.getMessage());        }    }    public static synchronized void change(SAPVO sap) throws ConexionSAPException {        Properties properties = new Properties();        // If connection is null create a new one        if(jcoProvider == null) jcoProvider = new JCOProvider();        properties.setProperty(DestinationDataProvider.JCO_ASHOST,        sap.getJCO_ASHOST());        properties.setProperty(DestinationDataProvider.JCO_SYSNR,         sap.getJCO_SYSNR());        properties.setProperty(DestinationDataProvider.JCO_CLIENT,        sap.getJCO_CLIENT());        properties.setProperty(DestinationDataProvider.JCO_USER,          sap.getJCO_USER());        properties.setProperty(DestinationDataProvider.JCO_PASSWD,        sap.getJCO_PASSWD());        properties.setProperty(DestinationDataProvider.JCO_LANG,          sap.getJCO_LANG());        try {            jcoProvider.changePropertiesForABAP_AS(properties);        } catch (Exception e) {            throw new ConexionSAPException(e.getMessage());        }    }    // Prevent instantiation by clone    @Override    public Object clone() throws CloneNotSupportedException {                throw new CloneNotSupportedException();    }}

JCo 提供者实现:

package es.grupotec.ejb.SAP;import com.sap.conn.jco.ext.DestinationDataEventListener;import com.sap.conn.jco.ext.DestinationDataProvider;import com.sap.conn.jco.ext.Environment;import es.grupotec.ejb.util.ConexionSAPException;import java.util.Properties;public class JCOProvider implements DestinationDataProvider {    private String SAP_SERVER = "JWM";    private DestinationDataEventListener eventListener;    private Properties ABAP_AS_properties;    public JCOProvider(){    }        public JCOProvider(SAPVO sap){        ABAP_AS_properties = new Properties();        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_ASHOST,        sap.getJCO_ASHOST());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_SYSNR,         sap.getJCO_SYSNR());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_CLIENT,        sap.getJCO_CLIENT());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_USER,          sap.getJCO_USER());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_PASSWD,        sap.getJCO_PASSWD());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_LANG,          sap.getJCO_LANG());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_POOL_CAPACITY, sap.getJCO_POOL_CAPACITY());        ABAP_AS_properties.setProperty(DestinationDataProvider.JCO_PEAK_LIMIT,    sap.getJCO_PEAK_LIMIT());        try {            if (!Environment.isDestinationDataProviderRegistered())                Environment.registerDestinationDataProvider(this);            else changePropertiesForABAP_AS(ABAP_AS_properties);        } catch (Exception ex) {            String msg = ex.getMessage();        }    }    @Override    public Properties getDestinationProperties(String name) {        if (name.equals(SAP_SERVER) && ABAP_AS_properties!=null) return ABAP_AS_properties;        else return null;            }    @Override    public boolean supportsEvents() {        return true;    }    @Override    public void setDestinationDataEventListener(DestinationDataEventListener eventListener) {        this.eventListener = eventListener;    } public void changePropertiesForABAP_AS(Properties properties) throws ConexionSAPException {        try {                        if (!Environment.isDestinationDataProviderRegistered()) {                if (ABAP_AS_properties == null) ABAP_AS_properties = properties;                Environment.registerDestinationDataProvider(this);            }            if (properties == null) {                if (eventListener != null) eventListener.deleted(SAP_SERVER);                ABAP_AS_properties = null;            } else {                ABAP_AS_properties = properties;                if (eventListener != null) eventListener.updated(SAP_SERVER);            }        } catch (Exception ex) {            throw new ConexionSAPException(ex.getMessage());                    } }    }

Answer 1

您的问题可能与这里涉及​​一些 native 代码有关。对于 JCo 3 来说也是如此。虽然 JCo 3 不再使用 native RFC 库，但它仍然需要 JNI 与 CPIC 层通信。

让 JVM 卸载 native 库是一项极其令人沮丧的工作。 JNI 规范规定，当与提供实现的类关联的类加载器被卸载时， native 库将被卸载，但在 JVM 中尝试强制类加载器卸载实际上是不可能的。

如果您的 EAR 文件包含 sapjco3.jar，每次重新加载代码时都会重新加载它。这很可能会导致异常，因为 native 库无法加载多次，并且几乎无法卸载 native 代码。因此，您可能会考虑将 sapjco3.jar 放在 J2EE 容器之外，让 J2EE 引擎在启动时加载该库一次，而不是将其放入 EAR 中并一遍又一遍地重新加载。