前言

在这篇自定义MVC框架思想中我已详细描述了工作原理及流程，本篇主要在此基础上继续做出优化，实现步骤如下：

自定义MVC实现

1. 导入XML配置文件

<?xml version="1.0" encoding="UTF-8"?>
<config><action path="/order" type="com.ycxw.servlet.OrderAction"><forward name="success" path="/index.jsp" redirect="true" /><forward name="failed" path="/register.jsp" redirect="false" /></action><action path="/book" type="com.ycxw.servlet.BookAction"><forward name="List" path="/book.jsp" redirect="false" /><forward name="toList" path="/index.jsp" redirect="true" /></action>
</config>

将其部署到Source Folder文件中

2. 导入XML解析建模

这里就不一一详细解说了，可以去 XML建模中了解详细建模实例。

3. 优化中央控制器

3.1 修改DisPathServlet中init初始化方法

在DisPathServlet的init方法中将原有Map集合方式替换成XML建模方式

// 通过xml建模方法进行储存
   private ConfigModel configModel;

   @Override
   public void init() throws ServletException {
       /**
       * 初始化存值就是给每个施工员根据施工证进行存档:
       */
       try {
           // configModel包含了所有的子控制器
           configModel = ConfigModelFactory.build();
       } catch (Exception e) {
           e.printStackTrace();
       }
   }

3.2 修改ActionServlet逻辑处理流程

根据请求路径名获取ActionModel

这里如果查不到指定对象，请认真检查xml文件的配置，以及截取的内容是否与xml配置相同

/*** 获取请求路径*/String uri = request.getRequestURI();// 截取bookuri = uri.substring(uri.lastIndexOf("/"), uri.lastIndexOf("."));// 要通过uri->> /book,在configModel对象中找ActionModel actionModel = configModel.pop(uri);// 判断没找对象等于空就抛出异常if (actionModel == null)throw new RuntimeException("action not config");/*** 获取config文件中action标签的type属性值* type指java类* com.ycxw.servlet.BookAction*/String type = actionModel.getType();

3.3 通过反射机制实例化子控制器类

package com.ycxw.framework;import java.lang.reflect.Method;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** 子控制器（action） 处理浏览器请求的类* * @author 云村小威** 2023年6月29日 下午8:30:32*/
public class Action {public String execute(HttpServletRequest request, HttpServletResponse response) throws Exception {// 获取methodName值，这里指前端点击功能传来的方法名String methodName = request.getParameter("methodName");//定义一个变量来保存返回值String res = "";/*** this--->BookAction/BlogAction/PermissionAction...可能是很多对象* 所以需要通过反射找到对象带request，response参数的methidName方法*/Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);m.setAccessible(true);// 动态调用其方法res = (String) m.invoke(this, request, response);return res ;}}

3.4 中央控制器将请求委托给子控制器处理

Action instance = (Action) Class.forName(type).newInstance();

// 业务代码执行后返回值

String execute = instance.execute(request, response);

3.5 根据请求结果码跳转页面

        // 通过返回值拿到，该方法结果是重定向还是转发，还是跳转哪个页面ForwardModel forwardModel = actionModel.pop(execute);if (forwardModel != null) {// 获取forwardModel是否从定向值boolean redirect = forwardModel.isRedirect();/*** 获取xml元素path值   */String path = forwardModel.getPath();// 判断是否为重定向if (redirect) {response.sendRedirect(request.getContextPath() + "/" + path);} else {request.getRequestDispatcher(path).forward(request, response);}}

4. 反射赋值

4.1 创建接口DriverModel<T>

package com.ycxw.framework;/*** 模型驱动接口* Book book = new Book();* @author 云村小威** @param <T>*/
public interface ModelDriver<T> {T getModel();
}

4.2 实现接口类

针对需要进行反射赋值的具体子控制器类，实现该接口DriverModel。

package com.ycxw.servlet;import java.io.IOException;
import java.util.Map;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.ycxw.entity.Book;
import com.ycxw.framework.Action;
import com.ycxw.framework.ModelDriver;/*** 施工类 继承子控制器* * @author 云村小威** @2023年6月29日 下午8:32:59*/
public class BookAction extends Action implements ModelDriver<Book>{//创建表对应的属性对象Book book = new Book();@Overridepublic Book getModel() {// TODO Auto-generated method stubreturn book;}public String load(HttpServletRequest req, HttpServletResponse resp) {//获取所有的参数Map<String, String[]> map = req.getParameterMap();System.out.println("Book查询的业务逻辑");try {resp.sendRedirect("index.jsp");} catch (IOException e) {e.printStackTrace();}return "List";}public String query(HttpServletRequest req, HttpServletResponse resp) {System.out.println("Book查询的业务逻辑");try {resp.sendRedirect("index.jsp");} catch (IOException e) {e.printStackTrace();}return "List";}public String edit(HttpServletRequest req, HttpServletResponse resp) {System.out.println("Book修改的业务逻辑");try {resp.sendRedirect("index.jsp");} catch (IOException e) {e.printStackTrace();}return "toList";}public String delete(HttpServletRequest req, HttpServletResponse resp) {System.out.println("Book删除的业务逻辑");try {resp.sendRedirect("index.jsp");} catch (IOException e) {e.printStackTrace();}return "toList";}public String add(HttpServletRequest req, HttpServletResponse resp) throws Exception {System.out.println("Book新增的业务逻辑");req.getRequestDispatcher("index.jsp").forward(req, resp);return "toList";}}

只要实现了DriverModel接口，则必须要对实体类进行初始化，并在getModel()方法中返回实例化后的对象。

4.3 反射对象赋值

再次修改ActionServlet中的业务逻辑处理流程，在反射调用方法之前，请先进行反射参数赋值操作。

/*** 获取config文件中action标签的type属性值* type指java类* com.ycxw.servlet.BookAction*/String type = actionModel.getType();// 通过反射创建对象Action instance;try {instance = (Action) Class.forName(type).newInstance();// 判断bookAction有没有实现ModelDriver接口if (instance instanceof ModelDriver) {// 向下转型获取接口方法ModelDriver md = (ModelDriver) instance;Object bean = md.getModel();// 把获取的参数保存到该对象中BeanUtils.populate(bean, request.getParameterMap());}

5. 完整优化中央控制器实例

5.1 完整 DisPathServlet类代码

package com.ycxw.framework;import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.apache.commons.beanutils.BeanUtils;import com.ycxw.framework.model.ActionModel;
import com.ycxw.framework.model.ConfigModel;
import com.ycxw.framework.model.ConfigModelFactory;
import com.ycxw.framework.model.ForwardModel;/*** 中央控制器（ActionServlet）* * @author 云村小威** @2023年6月29日 下午8:14:38*/
@WebServlet("*.action")
public class DisPathServlet extends HttpServlet {private static final long serialVersionUID = 1L;// 通过xml建模方法进行储存private ConfigModel configModel;@Overridepublic void init() throws ServletException {/*** 初始化存值就是给每个施工员根据施工证进行存档:*/try {// configModel包含了所有的子控制器configModel = ConfigModelFactory.build();} catch (Exception e) {e.printStackTrace();}}protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// http://localhost:8080/MVC_project/book.action?methodName=delete.../*** 获取请求路径*/String uri = request.getRequestURI();// 截取bookuri = uri.substring(uri.lastIndexOf("/"), uri.lastIndexOf("."));// 要通过uri->> /book,在configModel对象中找ActionModel actionModel = configModel.pop(uri);// 判断没找对象等于空就抛出异常if (actionModel == null)throw new RuntimeException("action not config");/*** 获取config文件中action标签的type属性值* type指java类* com.ycxw.servlet.BookAction*/String type = actionModel.getType();// 通过反射创建对象Action instance;try {instance = (Action) Class.forName(type).newInstance();// 判断bookAction有没有实现ModelDriver接口if (instance instanceof ModelDriver) {// 向下转型获取接口方法ModelDriver md = (ModelDriver) instance;Object bean = md.getModel();// 把获取的参数保存到该对象中BeanUtils.populate(bean, request.getParameterMap());}// 业务代码执行后返回值String execute = instance.execute(request, response);// 通过返回值拿到，该方法结果是重定向还是转发，还是跳转哪个页面ForwardModel forwardModel = actionModel.pop(execute);if (forwardModel != null) {// 获取forwardModel是否从定向值boolean redirect = forwardModel.isRedirect();/*** 获取xml元素path值   */String path = forwardModel.getPath();// 判断是否为重定向if (redirect) {response.sendRedirect(request.getContextPath() + "/" + path);} else {request.getRequestDispatcher(path).forward(request, response);}}} catch (Exception e) {e.printStackTrace();}}}

5.2 测试JSP页面

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>测试</title>
</head>
<body><a href="${pageContext.request.contextPath }/book.action?methodName=add&bid=1&bname=aa&price=13">增加</a><a href="${pageContext.request.contextPath }/book.action?methodName=delete">删除</a><a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a><a href="${pageContext.request.contextPath }/book.action?methodName=query">查询</a><a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
</body>
</html>