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Simple custom MVC

2022-06-30 03:05:00 【An Li Jiu Ge】

Preface

, Last time we shared the common paging （2）, The content shared today is custom MVC. I have shared it before mvc Pattern , What we want to share today is to define ourselves mvc.

One 、 Addition, deletion, modification and query of the original version

In the original version, each function corresponds to one 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(" Deal with the increasing business of books , call 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(" Deal with deleting books , call 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(" Deal with the editing business of books , call 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(" Deal with the query business of books , call 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> The current addition, deletion, modification and query </h3>
<a href="${pageContext.request.contextPath }/book/add"> increase </a>
<a href="${pageContext.request.contextPath }/book/del"> Delete </a>
<a href="${pageContext.request.contextPath }/book/update"> modify </a>
<a href="${pageContext.request.contextPath }/book/select"> see </a> 
</body>
</html>

 

  For each function, a separate servelt We can optimize .

<%@ 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> Optimization of problems with too many classes </h3>
<a href="${pageContext.request.contextPath }/book.action?methodName=add"> increase </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=del"> Delete </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=edit"> modify </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=list"> Inquire about </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=load"> The echo </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 {
//		 To distinguish the purpose of the current request , The purpose of adding, deleting, and modifying the query , Pass the method name to be called from the foreground to the background 
		String methodName = req.getParameter("methodName");		
		if("add".equals(methodName)){
//			 If a new request is passed from the foreground to the background , Then the background will call the new method 
			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(" Using a servlet Call in  list  Method ");
	}
	
//  private void load(HttpServletRequest req, HttpServletResponse resp) {
//		System.out.println(" Using a servlet Call in  list  Method ");
//	}
 
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  edit  Method ");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  del  Method ");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  add  Method ");
	}
}

 

Two 、 Add, delete, check and modify the reflection version

 

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 {
//		 To distinguish the purpose of the current request , The purpose of adding, deleting, and modifying the query , Pass the method name to be called from the foreground to the background 
		String methodName = req.getParameter("methodName");
//		methodName May be add/del/edit/list/load/xxx/yyy/aaa...
//		 What method does the front desk transfer , Call the corresponding method of the current class 
		try {
			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			m.setAccessible(true);
//			 Call the... Of the current class instance methodName Method 
			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(" Using a servlet Call in  list  Method ");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  list  Method ");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  edit  Method ");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  del  Method ");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  add  Method ");
	}
}

 

<%@ 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> Optimization of problems with too many classes </h3>
<a href="${pageContext.request.contextPath }/book.action?methodName=add"> increase </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=del"> Delete </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=edit"> modify </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=list"> Inquire about </a>
<a href="${pageContext.request.contextPath }/book.action?methodName=load"> The echo </a>
</body>
</html>

 

3、 ... and 、 Realization

First look at the schematic diagram ：

  Ideas as follows ：

First set up the central controller, that is ActionServlet

The corresponding handler is Action

ActionSupport Inherited from Action

 BooKAction Realization 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;
 
/**
 *  The central controller ：
 *  Main functions ： Accept browser requests , Find the corresponding handler 
 * 
 * @author Administrator
 *
 */
@WebServlet("*.action")
public class DispatcherServlet extends HttpServlet{
	private Map<String, Action> actions=new HashMap<String, Action>();
//	 Program startup , Will only load once 
	@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();
//		 To get /book, It's the last one / To the last point 
		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;
 
/**
 *  Sub controller ：
 *  The handler of the corresponding request 
 * @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 May be add/del/edit/list/load/xxx/yyy/aaa...
//		 What method does the front desk transfer , Call the corresponding method of the current class 
		try {
			Method m = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			m.setAccessible(true);
//			 Call the... Of the current class instance methodName Method 
			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(" Using a servlet Call in  list  Method ");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  list  Method ");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  edit  Method ");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  del  Method ");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  add  Method ");
	}
}
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(" Using a servlet Call in  list  Method ");
	}
	
	private void load(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  list  Method ");
	}
	
	private void edit(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  edit  Method ");
	}
 
	private void del(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  del  Method ");
	}
 
	private void add(HttpServletRequest req, HttpServletResponse resp) {
		System.out.println(" Using a servlet Call in  add  Method ");
	}
}

summary

The content shared this time is customized MVC, I hope it can help you , The preview of the next issue is customized MVC.

I'm nine songs , A programmer who likes programming .

If there is any mistake, please correct it , Thank you very much! .

 

原网站

版权声明
本文为[An Li Jiu Ge]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/181/202206300257450301.html

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