baseaction.java

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package edu.buptsse.sxjd.actions;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

import java.util.Locale;
import java.util.List;
import java.util.Iterator;
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 edu.buptsse.sxjd.common.Constants;
import edu.buptsse.sxjd.dao.DBManager;
import edu.buptsse.sxjd.service.BusinessException;

public abstract class BaseAction extends Action {
	protected DataSource dataSource = null;
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		ServletContext context = servlet.getServletContext();
		//取得数据源
		dataSource = (DataSource)context.getAttribute(Constants.DATASOURCE_JTDS_KEY);
		DBManager.setDs(dataSource);
		
		ActionForward forwardPage = null;
		try {
			forwardPage = executeAction(mapping, form, request, response);
		} catch (BusinessException ex) {
			forwardPage = processExceptions(request, mapping, ex);
		} catch (Throwable ex) {
			ex.printStackTrace();
			forwardPage = mapping.findForward(Constants.SYSTEM_ERROR_PAGE);
		}
		return forwardPage;
	}

	abstract public ActionForward executeAction(ActionMapping mapping,
			ActionForm form, HttpServletRequest request,
			HttpServletResponse response) throws BusinessException;

	protected ActionForward processExceptions(HttpServletRequest request,
			ActionMapping mapping, BusinessException ex) {
		ActionMessages errors = new ActionMessages();
		ActionForward forward = null;

		Locale locale = getLocale(request);

		processBaseException(errors, ex, locale);

		// Either return to the input resource or a configured failure forward
		String inputStr = mapping.getInput();
		ActionForward failureForward = mapping
				.findForward(Constants.APP_ERROR_PAGE);

		if (inputStr != null) {
			forward = new ActionForward(inputStr);
		} else if (failureForward != null) {
			forward = failureForward;
		}

		// See if this exception contains a list of subexceptions
		List exceptions = ex.getExceptions();
		if (exceptions != null && !exceptions.isEmpty()) {
//			int size = exceptions.size();
			Iterator iter = exceptions.iterator();

			while (iter.hasNext()) {
				// All subexceptions must be BaseExceptions
				BusinessException subException = (BusinessException) iter.next();

				processBaseException(errors, subException, locale);
			}
		}

		// Tell the Struts framework to save the errors into the request
		saveErrors(request, errors);

		// Return the ActionForward
		return forward;
	}

	protected void processBaseException(ActionMessages errors,
			BusinessException ex, Locale locale) {

		// Holds the reference to the ActionError to be added
		ActionMessage newActionMessage = null;

		// The errorCode is the key to the resource bundle
		String errorCode = ex.getMessageKey();
		/**
		 * If there are extra arguments to be used by the MessageFormat object,
		 * insert them into the argList. The arguments are context sensitive
		 * arguments for the exception; there may be 0 or more.
		 */
		Object[] args = ex.getMessageArgs();

		/**
		 * In an application that had to support I18N, you might want to format
		 * each value in the argument array based on its type and the user
		 * locale. For example, if there is a Date object in the array, it would
		 * need to be formatted for each locale.
		 */

		// Now construct an instance of the ActionError class
		if (args != null && args.length > 0) {
			// Use the arguments that were provided in the exception
			newActionMessage = new ActionMessage(errorCode, args);
		} else {
			newActionMessage = new ActionMessage(errorCode);
		}
		errors.add(ActionMessages.GLOBAL_MESSAGE, newActionMessage);
	}
}