关于SpringMVC的控制器（Controller）

学习目标：

SpringMVC的控制器（Controller）

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学习内容：

Controller的实现方式

• 实现Controller接口
• 注解实现Controller

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学习时间：

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学习产出：

控制器Controller

• 控制器负责解析用户的请求并将其转换为一个模型
• 在SpringMVC中一个控制器可以包含多个方法
• SpringMVC中对于Controller的配置方式
  • 实现Controller接口
  • 注解实现Controller

1、实现Controller接口

• 1、web.xml

<?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>

• 2、springmvc-servlet.xml

    <context:component-scan base-package="com.springmvc.controller"/>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>

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

• 3、创建Controller类

package com.springmvc.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 Test1Controller implements Controller {

    public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("msg","Controller");
        modelAndView.setViewName("test");
        return modelAndView;
    }
}

• 在springmvc-servlet.xml中为Test1Controller注册bean

<bean id="/test1" class="com.springmvc.controller.Test1Controller"/>

2、注解实现Controller

• 1、web.xml

<?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>

• 2、springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<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:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://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/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">


    <!-- 自动扫描指定的包，下面所有注解类交给IOC容器管理 -->
    <context:component-scan base-package="com.springmvc.controller"/>

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

<!--    <bean id="/test1" class="com.springmvc.controller.Test1Controller"/>-->
</beans>

• 3、Test2Controller

      //被这个注解的类中的所有方法，如果返回值是String，并且有具体页面可以跳转，那么就会被视图解析器解析;
      @Controller
      public class Test2Controller {
      
          @RequestMapping("/t2")
          public String test2(Model model){
              model.addAttribute("msg","注解实现Controller");
              return "test";
          }
      }

• 4、test.jsp

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