action.java

这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用struts,hebinate,xml等技术,有丰富的tag,role,navigation,session,dictio

/*
 * $Header: /sfroot/cvs/esimple/src/core/org/apache/struts/action/Action.java,v 1.1.1.1 2004/09/08 06:38:28 lava Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/09/08 06:38:28 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Struts", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
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 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
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package org.apache.struts.action;

import java.io.IOException;
import java.util.Locale;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.sql.DataSource;

import org.apache.struts.Globals;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;
import org.apache.struts.util.TokenProcessor;

/**
 * An <strong>Action</strong> is an adapter between the contents of an incoming
 * HTTP request and the corresponding business logic that should be executed to
 * process this request.  The controller (ActionServlet) will select an
 * appropriate Action for each request, create an instance (if necessary),
 * and call the <code>perform</code> method.</p>
 *
 * <p>Actions must be programmed in a thread-safe manner, because the
 * controller will share the same instance for multiple simultaneous
 * requests.  This means you should design with the following items in mind:
 * </p>
 * <ul>
 * <li>Instance and static variables MUST NOT be used to store information
 *     related to the state of a particular request.  They MAY be used to
 *     share global resources across requests for the same action.</li>
 * <li>Access to other resources (JavaBeans, session variables, etc.) MUST
 *     be synchronized if those resources require protection.  (Generally,
 *     however, resource classes should be designed to provide their own
 *     protection where necessary.</li>
 * </ul>
 *
 * <p>When an <code>Action</code> instance is first created, the controller
 * servlet will call <code>setServlet()</code> with a non-null argument to
 * identify the controller servlet instance to which this Action is attached.
 * When the controller servlet is to be shut down (or restarted), the
 * <code>setServlet()</code> method will be called with a <code>null</code>
 * argument, which can be used to clean up any allocated resources in use
 * by this Action.</p>
 *
 * @author Craig R. McClanahan
 * @author David Graham
 * @version $Revision: 1.1.1.1 $ $Date: 2004/09/08 06:38:28 $
 */
public class Action {


    // ----------------------------------------------------- Manifest Constants


    // NOTE - The definitions of manifest constant values have moved from
    // here to the org.apache.struts.Globals class, so that they can be
    // referenced without having to maintain a reference to the Action class
    // itself.  Any future new constant values should be defined there
    // instead of here.


    /**
     * The context attributes key under which our <code>ActionServlet</code>
     * instance will be stored.
     * @deprecated Use Globals.ACTION_SERVLET_KEY instead.
     * @since Struts 1.1
     */
    public static final String ACTION_SERVLET_KEY = Globals.ACTION_SERVLET_KEY;


    /**
     * <p>The base of the context attributes key under which our
     * <code>ModuleConfig</code> data structure will be stored.  This
     * will be suffixed with the actual module prefix (including the
     * leading "/" character) to form the actual attributes key.</p>
     *
     * <p>For each request processed by the controller servlet, the
     * <code>ModuleConfig</code> object for the module selected by
     * the request URI currently being processed will also be exposed under
     * this key as a request attribute.</p>
     *
     * @since Struts 1.1
     * @deprecated  Replaced by {@link org.apache.struts.Globals#MODULE_KEY}
     */
    public static final String APPLICATION_KEY = Globals.MODULE_KEY;


    /**
     * The context attributes key under which our <strong>default</strong>
     * configured data source (which must implement
     * <code>javax.sql.DataSource</code>) is stored,
     * if one is configured for this module.
     * @deprecated  Replaced by {@link org.apache.struts.Globals#DATA_SOURCE_KEY}
     */
    public static final String DATA_SOURCE_KEY = Globals.DATA_SOURCE_KEY;


    /**
     * The request attributes key under which your action should store an
     * <code>org.apache.struts.action.ActionErrors</code> object, if you
     * are using the corresponding custom tag library elements.
     * @deprecated  Replaced by {@link org.apache.struts.Globals#ERROR_KEY}
     */
    public static final String ERROR_KEY = Globals.ERROR_KEY;


    /**
     * The request attributes key under which Struts custom tags might store a
     * <code>Throwable</code> that caused them to report a JspException at
     * runtime.  This value can be used on an error page to provide more
     * detailed information about what really went wrong.
     * @deprecated  Replaced by {@link org.apache.struts.Globals#EXCEPTION_KEY}
     */
    public static final String EXCEPTION_KEY = Globals.EXCEPTION_KEY;


    /**
     * The context attributes key under which our
     * <code>org.apache.struts.action.ActionFormBeans</code> collection
     * is normally stored, unless overridden when initializing our
     * ActionServlet.
     *
     * @deprecated Replaced by collection in ModuleConfig
     */
    public static final String FORM_BEANS_KEY = Globals.FORM_BEANS_KEY;


    /**
     * The context attributes key under which our
     * <code>org.apache.struts.action.ActionForwards</code> collection
     * is normally stored, unless overridden when initializing our
     * ActionServlet.
     *
     * @deprecated Replaced by collection in ModuleConfig.
     */
    public static final String FORWARDS_KEY = Globals.FORWARDS_KEY;


    /**
     * The session attributes key under which the user's selected
     * <code>java.util.Locale</code> is stored, if any.  If no such
     * attribute is found, the system default locale
     * will be used when retrieving internationalized messages.  If used, this
     * attribute is typically set during user login processing.
     * @deprecated  Replaced by {@link org.apache.struts.Globals#LOCALE_KEY}
     */
    public static final String LOCALE_KEY = Globals.LOCALE_KEY;


    /**
     * The request attributes key under which our
     * <code>org.apache.struts.ActionMapping</code> instance
     * is passed.
     * @deprecated  Replaced by {@link org.apache.struts.Globals#MAPPING_KEY}
     */
    public static final String MAPPING_KEY = Globals.MAPPING_KEY;


    /**
     * The context attributes key under which our
     * <code>org.apache.struts.action.ActionMappings</code> collection
     * is normally stored, unless overridden when initializing our
     * ActionServlet.
     *
     * @deprecated Replaced by collection in ModuleConfig
     */
    public static final String MAPPINGS_KEY = Globals.MAPPINGS_KEY;


    /**
     * The request attributes key under which your action should store an
     * <code>org.apache.struts.action.ActionMessages</code> object, if you
     * are using the corresponding custom tag library elements.
     *
     * @since Struts 1.1
     * @deprecated  Replaced by {@link org.apache.struts.Globals#MESSAGE_KEY}
     */
    public static final String MESSAGE_KEY = Globals.MESSAGE_KEY;


    /**
     * <p>The base of the context attributes key under which our
     * module <code>MessageResources</code> will be stored.  This
     * will be suffixed with the actual module prefix (including the
     * leading "/" character) to form the actual resources key.</p>
     *
     * <p>For each request processed by the controller servlet, the
     * <code>MessageResources</code> object for the module selected by
     * the request URI currently being processed will also be exposed under
     * this key as a request attribute.</p>
     * @deprecated Use Globals.MESSAGES_KEY instead.
     */
    public static final String MESSAGES_KEY = Globals.MESSAGES_KEY;


    /**
     * The request attributes key under which our multipart class is stored.
     * @deprecated Use Globals.MULTIPART_KEY instead.
     */
    public static final String MULTIPART_KEY = Globals.MULTIPART_KEY;


    /**
     * <p>The base of the context attributes key under which an array of
     * <code>PlugIn</code> instances will be stored.  This
     * will be suffixed with the actual module prefix (including the
     * leading "/" character) to form the actual attributes key.</p>
     * @since Struts 1.1
     * @deprecated  Replaced by {@link org.apache.struts.Globals#PLUG_INS_KEY}
     */
    public static final String PLUG_INS_KEY = Globals.PLUG_INS_KEY;


    /**
     * <p>The base of the context attributes key under which our
     * <code>RequestProcessor</code> instance will be stored.  This
     * will be suffixed with the actual module prefix (including the
     * leading "/" character) to form the actual attributes key.</p>
     * @since Struts 1.1
     * @deprecated Use Globals.REQUEST_PROCESSOR_KEY instead.
     */
    public static final String REQUEST_PROCESSOR_KEY =
        Globals.REQUEST_PROCESSOR_KEY;


    /**
     * The context attributes key under which we store the mapping defined
     * for our controller serlet, which will be either a path-mapped pattern
     * (<code>/action/*</code>) or an extension mapped pattern
     * (<code>*.do</code>).
     * @deprecated Use Globals.SERVLET_KEY instead.
     */
    public static final String SERVLET_KEY = Globals.SERVLET_KEY;


    /**
     * The session attributes key under which our transaction token is
     * stored, if it is used.
     * @deprecated Use Globals.TRANSACTION_TOKEN_KEY instead.
     */
    public static final String TRANSACTION_TOKEN_KEY =
        Globals.TRANSACTION_TOKEN_KEY;

    /**
     * An instance of TokenProcessor to use for token functionality.
     * @TODO We can make this variable protected and remove Action's token methods
     * or leave it private and allow the token methods to delegate their calls.
     */
    private static TokenProcessor token = TokenProcessor.getInstance();


    // ----------------------------------------------------- Instance Variables


    /**
     * The system default Locale.
     */
    protected static Locale defaultLocale = Locale.getDefault();


    /**
     * The controller servlet to which we are attached.
     */
    protected ActionServlet servlet = null;


    // ------------------------------------------------------------- Properties


    /**
     * Return the controller servlet instance to which we are attached.
     */
    public ActionServlet getServlet() {

        return (this.servlet);

    }


    /**
     * Set the controller servlet instance to which we are attached (if
     * <code>servlet</code> is non-null), or release any allocated resources
     * (if <code>servlet</code> is null).
     *
     * @param servlet The new controller servlet, if any
     */
    public void setServlet(ActionServlet servlet) {

        this.servlet = servlet;

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Process the specified non-HTTP request, and create the
     * corresponding non-HTTP response (or forward to another web
     * component that will create it), with provision for handling
     * exceptions thrown by the business logic.
     * Return an {@link ActionForward} instance describing where and how
     * control should be forwarded, or <code>null</code> if the response has
     * already been completed.
     * <p>
     * The default implementation attempts to forward to the HTTP
     * version of this method.
     *
     * @param mapping The ActionMapping used to select this instance
     * @param form The optional ActionForm bean for this request (if any)
     * @param request The non-HTTP request we are processing
     * @param response The non-HTTP response we are creating
     *
     * @exception Exception if the application business logic throws
     *  an exception
     * @since Struts 1.1
     */
    public ActionForward execute(ActionMapping mapping,
                                 ActionForm form,
                                 ServletRequest request,
                                 ServletResponse response)
        throws Exception {