，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"%>
Insert title here
目前的增删改查
增加
删除
修改
查看
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"%>
Insert title here
类数量过多问题的优化
增加
删除
修改
查询
回显
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"%>
Insert title here
类数量过多问题的优化
增加
删除
修改
查询
回显
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;
@WebServlet("*.action")
public class DispatcherServlet extends HttpServlet{
private Map actions=new HashMap();
// 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;
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。
