SpringMVC学习（三）——Contorller配置总结及RequestMapping

╰半橙微兮° 2023-01-07 10:05 167阅读 0赞

### Contorller配置总结 ###

*  控制器Controller
 *   *  接口定义
     *  注解
     *  @RequestMapping

# 控制器Controller #

*  控制器复杂提供访问应用程序的行为，通常通过接口定义或者注解定义两种方式
 *  控制器负责解析用户的请求并将其转换为一个模型
 *  在Spring MVC中一个控制器类可以包含多个方法
 *  在Spring MVC中，对于Controller的配置方式有很多种

## 接口定义 ##

实现接口Controller定义控制器是较老的办法  
缺点是:一个控制器中只有一个方法，如果要多个方法则需要定义多个Controller;定义的方式比较麻烦;

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoYXJfbQ_size_16_color_FFFFFF_t_70]

<?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:spring-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>

<?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
            http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    
      
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
              id="internalResourceViewResolver">
            
            <property name="prefix" value="/WEB-INF/jsp/"/>
            
            <property name="suffix" value=".jsp"/>
    
        </bean>
        <bean name="/hhh" class="com.my.controller.HelloController"/>
    
    </beans>

Controller是一个接口，在org.springframework.web.servlet.mvc包下，接口中只有一个方法是用来处理请求且返回一个模型：

package com.my.controller;
    
    import org.springframework.web.servlet.ModelAndView;
    import org.springframework.web.servlet.mvc.Controller;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    //只要实现了controller接口的类，就说明这就是一个控制器了
    public class HelloController implements Controller {
        
        public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
        
            ModelAndView mv = new ModelAndView();
            mv.addObject("msg","HelloController");
            mv.setViewName("hhh");
            return mv;
    
        }
    }

![在这里插入图片描述][2021011620325585.png]

## 注解 ##

Spring可以使用扫描机制来找到应用程序中所有基于注解的控制器类，为了保证Spring能找到你的控制器，需要在配置文件中声明组件扫描。  
![在这里插入图片描述][20210116204253645.png]  
增加Controller类，使用注解

package com.my.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    @Controller
    public class HelloController2 {
        
        //映射访问路径
        @RequestMapping("/t2")
        public String index(Model model){
        
            //Spring MVC会自动实例化一个Model对象用于向视图中传值
            model.addAttribute("msg","HelloController2");
            //返回视图
            return "hhh";
        }
    }

<?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
            http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    
        
        <context:component-scan base-package="com.my.controller"/>
       
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
              id="internalResourceViewResolver">
            
            <property name="prefix" value="/WEB-INF/jsp/"/>
            
            <property name="suffix" value=".jsp"/>
    
        </bean>
    </beans>

![在这里插入图片描述][20210116205510462.png]

## @RequestMapping ##

·**@RequestMapping注解用于映射url到控制器类或一个特定的处理程序方法。可用于类或方法上。用于类上，表示类中的所有响应请求的方法都是以该地址作为父路径。**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoYXJfbQ_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][20210116215246458.png]

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[2021011620325585.png]: /images/20221119/af84f169597842ff8d7342ba8adb0e24.png
[20210116204253645.png]: /images/20221119/e6db9c22a6444bc995ae0d804adbad23.png
[20210116205510462.png]: /images/20221119/65b1f9c48e3040bc9f0f6cb2b550c46d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoYXJfbQ_size_16_color_FFFFFF_t_70 1]: /images/20221119/dd3146d5c94f4ed591a2f90d0dc0ef77.png
[20210116215246458.png]: /images/20221119/901823eeab964d34a5db284533c31ab5.png