frontcontroller.java

mvc框架

package com.strutslet.core;

import javax.servlet.*;
import javax.servlet.http.*;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.strutslet.model.ActionModel;
import com.strutslet.util.ConfigUtil;
import com.strutslet.util.Constant;

import java.io.*;
import java.util.Map;
import java.util.logging.Logger;

/**
 * 前端控制器
 * @author dennis
 */
public class FrontController extends HttpServlet {
	 private static final Log log = LogFactory.getLog(FrontController.class);	

	@Override
	public void init() throws ServletException {
		ServletContext context=getServletContext();
		String config_file =getServletConfig().getInitParameter("config");
		String dispatcher_name=getServletConfig().getInitParameter("dispatcher");
		if (config_file == null || config_file.equals(""))
			config_file = "/WEB-INF/strutslet-config.xml";
		if(dispatcher_name==null||dispatcher_name.equals(""))
			dispatcher_name=Constant.DEFAULT_DISPATCHER;
				
		try {
			Map<String, ActionModel> resources = ConfigUtil.newInstance()
					.parse(config_file, context);
			context.setAttribute(Constant.ACTIONS_ATTR, resources);
			log.info("初始化strutslet配置文件成功");
		} catch (Exception e) {
			log.error("初始化strutslet配置文件失败");
			e.printStackTrace();
		}
		
		try{
			Class c = Class.forName(dispatcher_name);
		    Dispatcher	dispatcher = (Dispatcher) c.newInstance();
		    context.setAttribute(Constant.DISPATCHER_ATTR, dispatcher);
		    log.info("初始化Dispatcher成功");
		}catch(Exception e) {
			 log.error("初始化Dispatcher失败");
    		e.printStackTrace();
		}
	}

	/**
	 * Handle GET requests by forwarding to a common method
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		process(request, response);
		// getServletConfig().getInitParameter("")
	}

	/**
	 * Handle POST requests by forwarding to a common method
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		process(request, response);
	}

	/**
	 * Process a request by forwarding to the appropriate dispatcher
	 */
	protected void process(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		ServletContext context = getServletContext();

        //获取action的path 
		String reqURI = request.getRequestURI();
		int i=reqURI.lastIndexOf(".");
		String contextPath=request.getContextPath();
		String path=reqURI.substring(contextPath.length(),i);
		
		request.setAttribute(Constant.REQUEST_ATTR, path);
		Dispatcher dispatcher = (Dispatcher) context.getAttribute(Constant.DISPATCHER_ATTR);

		// make sure we don't cache dynamic data
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");

		// use the dispatcher to find the next page
		String nextPage = dispatcher.getNextPage(request, context);

		// forward control to the view
		RequestDispatcher forwarder = request.getRequestDispatcher("/"
				+ nextPage);
		forwarder.forward(request, response);
	}
}