This article thoroughly talks about Controller annotations and RequestMapping annotations. If you don't know, you have to take a look.

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    page

    Create a new folder page under WEB-INF, and then create a new page first.jsp.

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h1>${message}</h1>
</body>
</html>

    Spring core configuration file

    Here you can configure the public prefix and suffix of a page, and you only need to give the view name in the control class.

    <?xml version="1.0" encoding="UTF8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="
    http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd
    http://www.springframework.org/schema/tx  https://www.springframework.org/schema/tx/spring-tx.xsd
    http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/page/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

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    Web.xml configuration file

    This section is fixed, you don't need to register each Servlet separately, you only need to register a front controller DispatcherServlet.

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:SpringMVC-Servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

    Controller

    SpringMVC provides many ways to mark a class as a control class; it can be done by implementing the Controller interface or by using Controller annotations.

    Controller interface

    Write a control class and then implement the Controller interface, rewrite the handleRequest method to realize the acceptance processing of the request, and finally return a ModelAndView class.

    package com.controller;


import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class InterfaceController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        ModelAndView mv = new ModelAndView();
        /*
            1. 调用业务层
            2. 封装数据、以及给出需要响应的视图名
            3. 返回ModelAndView对象交给适配器
         */
        mv.addObject("message","实现Controller接口");        //数据
        mv.setViewName("first");            //响应的视图名
        return mv;
    }
}

    Register the control class and give an access path. Finally visit localhost:8080/project name/inter/first; you can visit.

    <bean id="/inter/first" class="com.controller.InterfaceController"/>

    Controller annotation

    I first learned about this annotation when I was in Spring. At that time, I only knew roughly that it could be used to register beans, and I didn't know that it could mark a class as a control class. The Controller annotation can register a bean because it is decorated by the Component annotation, and the Component annotation has the ability to register a bean.

    package com.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class AnnotationController {

    @RequestMapping("/Annota/first")            //注册映射路径
    private String firstServlet(Model model){
        model.addAttribute("message", "Controller注解");            //封装数据
        return "first";            //给出视图名
    }
}

    The Controller annotation can be used to mark the class as a control class, and each method in it can be considered a Servlet. Compared to implementing the Controller interface, the annotation version is more powerful. When there are multiple Servlets, you only need to write multiple methods!

    Only a little bit of annotation driver and MVC annotation support need to be extended in the SpringMVC core configuration file.

    <!-- 扫描包注解 -->
<context:component-scan base-package="com.controller"/>
<!-- mvc注解驱动 -->
<mvc:annotation-driven/>
<!-- 默认处理器、过滤器 -->
<mvc:default-servlet-handler/>

    RequestMapping annotation

    The RequestMapping annotation is equivalent to registering a Servlet-a mapping of the path, indicating which method will be passed to access the /xxx path and nothing more; using this annotation can get rid of the core configuration file, and put a fixed template code in each configuration file. Controller annotation + RequestMapping annotation is used in the control class.

    RequestMapping annotation modification class

    When modifying the class, it means that each method under it needs to add a prefix path;

    @Controller
@RequestMapping("/father")
public class RequestMappingController {

    @RequestMapping("/test1")
    private String test1(){
    
        return "test1";
    }
    
    @RequestMapping("/test2")
    private String test2(){
    
        return "test2";
    }
}

    test1 real path: localhost:8080/project name/father/test1
    test2 real path: localhost:8080/project name/father/test2

    Modification method

    It is only the specific path when modifying the method.

    @Controller
public class RequestMappingController {

    @RequestMapping("/test1")
    private String test1(){
    
        return "test1";
    }
    
    @RequestMapping("/father/test2")
    private String test2(){
    
        return "test2";
    }
}

    At last

    Thank you for seeing this. If you think the article is helpful to you, remember to like it. Thank you for your support!

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