当前位置：网站首页>简单自定义mvc

简单自定义mvc

2022-06-30 02:58:00 【安离九歌】

前言

，上次我们分享了通用分页（2），今天分享的内容是自定义MVC。此前我也分享过了mvc模式，今天要分享的是定义一个我们自己mvc。

一、最初版增删改查

最初版的增删改查每一个功能对应了一个servlet。

package com.zhw.web;
 
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;
@WebServlet("/book/add")
public class AddBookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("处理书籍的增加业务，调用BookBiz");
	}
}
package com.zhw.web;
 
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;
@WebServlet("/book/del")
public class DelBookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("处理书籍的删除业务，调用BookBiz");
	}
}
package com.zhw.web;
 
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;
@WebServlet("/book/edit")
public class EditBookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("处理书籍的编辑业务，调用BookBiz");
	}
}

 

package com.zhw.web;
 
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;
@WebServlet("/book/list")
public class ListBookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("处理书籍的查询业务，调用BookBiz");
	}
}

 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

 <h3>目前的增删改查</h3>
<a href="${pageContext.request.contextPath }/book/add">增加</a>
<a href="${pageContext.request.contextPath }/book/del">删除</a>
<a href="${pageContext.request.contextPath }/book/update">修改</a>
<a href="${pageContext.request.contextPath }/book/select">查看</a> 
</body>
</html>

 

 对于每一个功能都需要一个单独的servelt我们可以进行优化。

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h3>类数量过多问题的优化</h3>
<a href="${pageContext.request.contextPath }/book.action?methodName=add">增加</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=del">删除</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
</body>
</html>

 

package com.zhw.servlet;
 
import java.io.IOException;
import java.lang.reflect.Method;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/book.action")
public class BookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		为了区分当前请求的目的，增删改查的目的，就从前台将要调用的方法名传递到后台
		String methodName = req.getParameter("methodName");		
		if("add".equals(methodName)){
//			如果前台传递到后台的是一个新增的请求，那么后台就调用新增方法
			add(req,resp);
		}
		else if("del".equals(methodName)) {
			del(req,resp);
		}
		else if("edit".equals(methodName)) {
			edit(req,resp);
		}
		else if("list".equals(methodName)) {
			list(req,resp);
		}
//       else if("load".equals(methodName)) {
//			load(req,resp);
//		}
	}
 
	private void list(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
//  private void load(HttpServletRequest req, HttpServletResponse resp) {
//		System.out.println("在用一个servlet中调用 list 方法");
//	}
 
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 edit 方法");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 del 方法");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 add 方法");
	}
}

 

二、反射版增删查改

 

package com.zhw.web;
 
import java.io.IOException;
import java.lang.reflect.Method;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/book.action")
public class BookServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		为了区分当前请求的目的，增删改查的目的，就从前台将要调用的方法名传递到后台
		String methodName = req.getParameter("methodName");
//		methodName可能是add/del/edit/list/load/xxx/yyy/aaa...
//		前台传递什么方法，就调用当前类的对应方法
		try {
			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			m.setAccessible(true);
//			调用当前类实例的methodName方法
			m.invoke(this, req,resp);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} 
		
 
	private void list(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 edit 方法");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 del 方法");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 add 方法");
	}
}

 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h3>类数量过多问题的优化</h3>
<a href="${pageContext.request.contextPath }/book.action?methodName=add">增加</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=del">删除</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=edit">修改</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=list">查询</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=load">回显</a>
</body>
</html>

 

三、实现

首先看一下原理图：

 思路如下：

先建立中央控制器也就是ActionServlet

对应处理人就是Action

ActionSupport继承于Action

 BooKAction实现ActionSupport

package com.zhw.framework;
 
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
 
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 com.zhw.web.BooKAction;
 
/**
 * 中央控制器：
 * 主要职能：接受浏览器请求，找到对应的处理人
 * 
 * @author Administrator
 *
 */
@WebServlet("*.action")
public class DispatcherServlet extends HttpServlet{
	private Map<String, Action> actions=new HashMap<String, Action>();
//	程序启动时，只会加载一次
	@Override
	public void init() throws ServletException {
		actions.put("/book", new BooKAction());
//		actions.put("/order", new BooKAction());
	}
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//http://localhost:8080/mvc/book.aciton?methodName=list
		String uri = req.getRequestURI();
//		要拿到/book，就是最后一个/到最后一个点的位置
		uri=uri.substring(uri.lastIndexOf("/")
						, uri.lastIndexOf("."));
		Action action = actions.get(uri);
		System.out.println(action);
		action.execute(req, resp);
	}
	
}
package com.zhw.framework;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * 子控制器：
 * 对应请求的处理人
 * @author Administrator
 *
 */
public interface Action {
	void execute(HttpServletRequest req, HttpServletResponse resp);
}
package com.zhw.framework;
 
import java.lang.reflect.Method;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class ActionSupport implements Action{
 
	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp) {
		String methodName = req.getParameter("methodName");
//		methodName可能是add/del/edit/list/load/xxx/yyy/aaa...
//		前台传递什么方法，就调用当前类的对应方法
		try {
			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			m.setAccessible(true);
//			调用当前类实例的methodName方法
			m.invoke(this, req,resp);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} 
	}
	
	private void list(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 edit 方法");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 del 方法");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 add 方法");
	}
}
package com.zhw.web;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.zhw.framework.Action;
import com.zhw.framework.ActionSupport;
 
public class BooKAction extends ActionSupport {
	
	private void list(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 list 方法");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 edit 方法");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 del 方法");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println("在用一个servlet中调用 add 方法");
	}
}

总结

这次分享的内容是自定义MVC，希望对你能有帮助，下期预告自定义MVC。

我是九歌，一个喜欢编程的程序员。

如有错误还望指正，谢谢啦。

 

原网站

版权声明
本文为[安离九歌]所创，转载请带上原文链接，感谢
https://blog.csdn.net/qq_62331938/article/details/125473182

边栏推荐

猜你喜欢

随机推荐