logonaction.java

这是一个基于struts框架的地址薄程序

package addressbook.actions;


import java.io.IOException;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.MissingResourceException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.util.MessageResources;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import addressbook.Constants;
import addressbook.model.UserBean;
import addressbook.forms.LogonForm;

/**
 * <strong>LogonAction</strong> provides the login mechanism
 * for the sample application. The username/password pair that
 * is entered by the user will be compared against the database
 * values that where read in at application startup. An error will
 * be reported if the username/password don't match, otherwise
 * a <code>User</code> Object will be inserted into the session
 * to indicate that the user is currently logged in.
 */
public final class LogonAction extends AbstActionBase {
	private Log log =
        LogFactory.getLog(this.getClass().getName());


public ActionForward execute(ActionMapping mapping,
				 ActionForm form,
				 HttpServletRequest request,
				 HttpServletResponse response)
	throws Exception {

	String userName=null;
	String password=null;


	Locale locale = getLocale(request);
	MessageResources messages = getResources(request);

	UserBean user = null;
	// Demonstrate a trace call to the logger
	if (log.isTraceEnabled()) {
		log.trace("LogonAction: entering method");
	}
	// Validate the request parameters specified by the user
	ActionMessages errors = new ActionMessages();
	if (form != null){
	 	userName = ((LogonForm) form).getUserName();
	 	password = ((LogonForm) form).getPassword();
	}
	Hashtable database = (Hashtable)
	  servlet.getServletContext().getAttribute(Constants.DATABASE_KEY);
	if (database == null)
            errors.add(ActionMessages.GLOBAL_MESSAGE,
                       new ActionMessage("error.database.missing"));
	else {
	    user = (UserBean) database.get(userName);
	    if ((user != null) && !user.getPassword().equals(password)){
			user = null;
		}
	    if (user == null)
                errors.add(ActionMessages.GLOBAL_MESSAGE,
                           new ActionMessage("error.password.mismatch"));
	}

	// Report any errors we have discovered back to the original form
	if (!errors.isEmpty()) {
	    saveErrors(request, errors);
	    return (new ActionForward(mapping.getInput()));
	}


	// Save our logged-in user in the session
	HttpSession session = request.getSession();
	session.setAttribute(Constants.USER_KEY, user);
	// Demonstrate a debug call to the logger
	if (log.isDebugEnabled()) {
		log.debug("LogonAction: User '" + user.getUserName() +
	       "' logged on in session " + session.getId());
	}
        // Remove the obsolete form bean
	if (mapping.getAttribute() != null) {
            if ("request".equals(mapping.getScope()))
                request.removeAttribute(mapping.getAttribute());
            else
                session.removeAttribute(mapping.getAttribute());
        }

	// Forward control to the specified success URI
	return (mapping.findForward(Constants.FORWARD_SUCCESS));

    }

}