"Struts"的简易实现

java 代码

package com.viwo.web.acion;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.Map;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.digester.Digester;
import org.apache.log4j.Logger;
import org.xml.sax.SAXException;

import com.viwo.web.config.ConfigAction;
import com.viwo.web.config.ConfigForward;
import com.viwo.web.config.ViwoConfig;

/**
 * the Frameword's entry,the Controller of All
 *
 * @author viwo
 *
 */
public class ViwoServlet extends HttpServlet {

 private final static Logger logger = Logger.getLogger(ViwoServlet.class);
    public void doGet(HttpServletRequest request,
               HttpServletResponse response)
         throws IOException, ServletException {

        process(request, response);

     }

     public void doPost(HttpServletRequest request,
                HttpServletResponse response)
         throws IOException, ServletException {

         process(request, response);

     }

     /**
      * the main method of ViwoServlet
      *
      * get the properties from web.xml and viwo-config.xml
      *
      * use these properties and url info to initialize and select appropriate action
      * and method to go.
      *
      * @param request
      * @param response
      */
     protected void process(HttpServletRequest request,
                HttpServletResponse response)
      throws IOException, ServletException {
         String config = getServletConfig().getInitParameter("config");
         String template = getServletConfig().getInitParameter("template");
         logger.info("[viwo]-->[enter process]-->[config:]"+config);

         String forward = "";
         Object returnValue = null;
            String url = request.getRealPath(config);
            logger.debug("[viwo]-->[process]-->[url:]"+url);

            String requestURI = request.getRequestURI();
            int lastdot = requestURI.lastIndexOf(".");
            int lastbias = requestURI.lastIndexOf("/");
            int lastbiasbutone = requestURI.lastIndexOf("/",lastbias-1);
            String method = requestURI.substring(lastbias+1,lastdot);
            String action = requestURI.substring(lastbiasbutone+1,lastbias);
            Object actionObject = null;
            try
            {
             ViwoConfig viwoConfig = getViwoConfig(url);
             Map cfgActionMap  = viwoConfig.getActionMap();
             Map cfgForwardMap = viwoConfig.getForwardMap();

             if(cfgActionMap.get(action)!=null)
             {
              ConfigAction ca = (ConfigAction)cfgActionMap.get(action);
              action = ca.getType();
             }

             actionObject = Class.forName(action).newInstance();
                Method m = getMethod(actionObject,method);
                if(m != null)
                {
                 returnValue = m.invoke(actionObject,new Object[]{request,response});
                 //如果方法调用返回的是null，则直接返回。
                 if(returnValue==null)
                  return;
                 //根据web.xml中配置的template参数决定选择使用哪种模板引擎。
                 if(template!=null)
                  forward = "/"+returnValue+"."+template;
                 else
                  forward = "/"+returnValue+".jsp";

                 if(cfgForwardMap.get(returnValue)!=null)
                 {
                  ConfigForward cf = (ConfigForward)cfgForwardMap.get(returnValue);
                  forward = cf.getPath();
                 }

                 logger.debug("[viwo]-->[process]-->[forward:]"+forward);
                 RequestDispatcher rd = getServletContext().getRequestDispatcher(forward);
                 rd.forward(request, response);
                }
                else
                {
                 logger.error("[viwo]-->[process]-->"+"There haven't the "+method+" Method,Please check URL!");
                 response.getWriter().print("There haven't the "+method+" Method,Please check URL!");
                }

   }
            catch (ClassNotFoundException e)
   {
             logger.error("[viwo]-->[process]-->"+"There haven't the "+action+" Class,Please check URL!");
             response.getWriter().print("There haven't the "+action+" Class,Please check URL!");
   }
            catch (NoClassDefFoundError e)
            {
             logger.error("[viwo]-->[process]-->"+"There haven't the "+action+" Class,Please check URL!");
             response.getWriter().print("There haven't the "+action+" Class,Please check URL!");
            }
            catch (Exception e)
            {
             System.out.println(e.getMessage());
             logger.error("[viwo]-->[process]-->"+e.getMessage());
            }

     }

     /**
      * the method for parsing config file for ViwoServlet
      *
      * put the properties from viwo-config.xml to and object of ViwoConfig
      *
      * @param url
      * @return ViwoConfig
      */
     private ViwoConfig getViwoConfig(String url) throws IOException, SAXException
     {
      Digester digester = new Digester();
         digester.setValidating(false);
         digester.addObjectCreate("viwo-config", "com.viwo.web.config.ViwoConfig");

         digester.addObjectCreate("viwo-config/action", "com.viwo.web.config.ConfigAction");
         digester.addSetProperties("viwo-config/action");
         digester.addSetNext("viwo-config/action", "addAction", "com.viwo.web.config.ConfigAction");

         digester.addObjectCreate("viwo-config/forward", "com.viwo.web.config.ConfigForward");
         digester.addSetProperties("viwo-config/forward");
         digester.addSetNext("viwo-config/forward", "addForward", "com.viwo.web.config.ConfigForward");
         ViwoConfig viwoConfig = (ViwoConfig) digester.parse(new File(url));
         return viwoConfig;

     }

     /**
      * get the actionObject's method Method
      *
      * @param actionObject
      * @param method
      * @return Method
      */
     private Method getMethod(Object actionObject,String method)
       throws IOException
     {

     Method[] methods = actionObject.getClass().getMethods();
     if(methods==null||methods.length==0)
     {
      return null;
     }
     for(int i=0;i      {
      if(methods[i].getName().equals(method))
       return methods[i];
     }
     return null;

     }

}

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