一个servlet类反射相应实现servlet功能的普通类

来源：互联网发布：小三转正后的婚姻知乎编辑：程序博客网时间：2024/06/08 12:00

package com.framework;

import java.io.IOException;
import java.lang.reflect.Method;

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

public class ActionServlet extends HttpServlet {

    String actionPackage="";

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try{
            System.out.println("===进入 "+this.getClass().getName());
            String url = request.getRequestURI();

            String actionName = "";
            String methodName = "";
            try{
                System.out.println("===请求是: "+ url);
                actionName = url.substring(url.lastIndexOf('/')+1, url.lastIndexOf('.'));
                System.out.println("===类名是: "+ actionName);
                methodName = url.substring(url.lastIndexOf('.')+1);
                System.out.println("===方法是: "+methodName);
            }catch(Exception e){
                throw new ActionException("===不合法的url:["+url+"]/t"+e.getMessage(),e.getCause());
            }

            Object action = findAction(actionName);
            System.out.println("/t===获得Action:"+ action);

            Method method = findMethod(action,methodName);
            System.out.println("/t===获得方法:"+method);

            //调用 javaBean
            ActionForward returnValue = (ActionForward)method.invoke(action, request,response);

            if(null == returnValue) throw new ActionException("===["+actionName+"]的["+methodName+"]没有返回值!");

            System.out.println("/t===跳转的url:"+returnValue.getContent());

            //负责跳转
            if(returnValue.getType()==ActionForward.redirect_true){
                response.sendRedirect(request.getContextPath()+returnValue.getContent());
            }else if(returnValue.getType() == ActionForward.redirect_false){
                request.getRequestDispatcher(returnValue.getContent()).forward(request, response);
            }else{
                response.getWriter().print(returnValue.getContent());
            }

        }catch (Exception e) {
            e.printStackTrace();
        }
    }//doGet()

    private Object findAction(String acName)throws Exception{
        Object action = null;
        String actionPath = actionPackage+"."+acName;
        try{
            Class clz = Class.forName(actionPath);//加载类    //UsersAction action;
            action = clz.newInstance();                            //action = new UsersAction();
        }catch(Exception e){
            throw new ActionException("===给定的路径["+actionPath+"]不能得到类实例/t"+e.getMessage(),e.getCause());
        }
        return action;
    }//findAction()

    private Method findMethod(Object action,String mdName) throws Exception{
        Method md = null;
        try{
            md = action.getClass().getMethod(mdName, HttpServletRequest.class,HttpServletResponse.class);
        }catch(Exception e){
            throw new ActionException("===类型["+action.getClass()+"]不那得到["+mdName+"(HttpServletRequest,HttpServletResponse)]方法/t"+e.getMessage(),e.getCause());
        }
        return md;
    }//findMethod()

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        doGet(req, resp);
    }

    @Override
    public void init() throws ServletException {
        this.actionPackage = this.getInitParameter("actionpackage");
    }

}