Thymeleaf 一个Servlet处理多个请求（六）

一、问题：针对某一个模块，需要编写多个servlet

如用户的增删改查、登录、注册:

FindServlet

LoginServlet

RegisterServlet

...............

二、解决：一个模块对应一个Servlet处理，并实现不同业务逻辑

2.1、每个模块定义一个Servlet，比如用户模块对应的UserServlet

2.2、UserServlet是用来处理用户模块的所有请求，那么就要区分不同请求，通过请求参数区分

<a th:href="@{/UserServlet(method='1ogin')}">登录请求</a>

2.3、如果所有的请求处理都放在doPost或doGet里面

（1）如果请求过多，会造成doGet和doPost代码量特别大，那么把不同的请求代码放到指定的方法，实现代码的分隔；

（2）如果请求过多，那么需要大量的if判定

（a) 根据方法名调用对应的方法【反射机制】

(b) 传递过来的请求参数必须和方法名一致。

2.4、每个Servlet都需要用到通过反射机制调用对应的方法这套业务，可以提取公共的父类【ModelServlet】，让ModelServlet继承HttpServle，再把doGet和doPost、根据方法名，通过反射机制调用对应的方法这套业务。之后创建Servlet，就不要继承HttpServlet，继承ModelServlet

三、代码实现

welcome.html

html 复制代码

<!DOCTYPE html>
<!--导入thymeleaf包-->
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h3>用户模块</h3>
<a th:href="@{/userServlet(method='login')}">登录</a><p/>
<a th:href="@{/userServlet(method='register')}">注册</a><p/>
<a th:href="@{/userServlet(method='logout')}">注销</a><p/>
<a th:href="@{/userServlet(method='update')}">更新</a><p/>
<a th:href="@{/userServlet(method='delete')}">删除</a><p/>
</body>
</html>

WelcomeServlet.java

java 复制代码

package org.hlx.servlet;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.hlx.thymeleaf.CustomTemplateEngine;

import java.io.IOException;
import java.math.BigDecimal;

@WebServlet("/welcome.html")
public class WelcomeServlet extends HttpServlet {
      @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 获取模板引擎对象
        CustomTemplateEngine templateEngine = CustomTemplateEngine.getInstance(req);

        // 处理请求并响应结果
        templateEngine.processTemplate("welcome", req, resp);
    }

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

ModelServlet.java

java 复制代码

package org.hlx.servlet;

import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.lang.reflect.Method;

/**
 * @author : HLX
 * @ClassName :ModelServlet
 * @date : 2026/1/13 15:02
 * @Version :1.0
 * @Description: TODO
 * @modyified By :
 */
public class ModelServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws jakarta.servlet.ServletException, java.io.IOException {
       doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws jakarta.servlet.ServletException, java.io.IOException {
        //获取请求的参数
        String method = req.getParameter("method");
        try {
            //获取Method对象
            Method methodObject = this.getClass().getDeclaredMethod(method, HttpServletRequest.class, HttpServletResponse.class);

            //暴力破解
            methodObject.setAccessible(true);

            //执行方法
            methodObject.invoke(this, req, resp);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

UserServlet.java

java 复制代码

package org.hlx.servlet;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;

/**
 * @author : HLX
 * @ClassName :UserSevlet
 * @date : 2026/1/13 14:55
 * @Version :1.0
 * @Description: TODO
 * @modyified By :
 */
@WebServlet("/userServlet")
public class UserServlet extends ModelServlet {
    public void login(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行login方法...");
    }
    public void register(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行register方法...");
    }
    public void logout(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行logout方法...");
    }
    public void update(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行update方法...");
    }
    public void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("执行delete方法...");
    }
}

四、运行效果

http://localhost:8080/ThymeleafServlet_01/welcome.html