SpringMVC学习日志一

Posted 2022-09-28 kklb

一、MVC流程图

　　1.传统MVC

 

　　2.SpringMVC

二、一个简单的SpringMVC

　　1.导入相关的包

　　2.配置DispatcherServlet 在web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>SpringMVC-01</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- springmvc的配置文件必须在【servlet-name】-servlet.xml -->
  <!--  
  <servlet>
      <servlet-name>springMVC</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>springMVC</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping> -->
  
  <servlet>
      <servlet-name>springMVC</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
       
       <!-- DispatcherServlet加载指定的springmvc的配置文件 -->
       <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springMVC-annotation.xml</param-value>
       </init-param>
  </servlet>
  <servlet-mapping>
       <servlet-name>springMVC</servlet-name>
       <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  
</web-app>

　　3.配置springmvc的配置文件

 

<?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">

    <!-- 包扫描：扫描 -->
    <context:component-scan base-package="com.zhiyou100.klb.annotation"></context:component-scan>
    
    <!-- 开启注解驱动 -->
    <mvc:annotation-driven />
    
    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/view/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans> 

 

　　4.建立Controller

package com.zhiyou100.klb.annotation;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller //等价于<bean class="com.zhiyou100.klb.annotation.MyController" />
public class MyController 
    
    @RequestMapping("/list.do")    //requestMapping:表示的就是你的访问地址
    public ModelAndView list() 
        System.out.println("查询所有");
        ModelAndView mv = new ModelAndView();
        mv.setViewName("login");
        mv.addObject("userName", "查询所有");
        return mv;
    
    
    @RequestMapping("/delete.do")
    public String delete() 
        System.out.println("删除");
        return "login";
    
    
    @RequestMapping("/save.do")
    public String save() 
        System.out.println("保存");
        return "login";
    
    

　三、SpringMVC的流程

1. 客户发出请求。http://localhost:8080/springmvc-01/my.do
2. 到达web.xml文件中 DispatcherServlet.查看是否符合url的要求
3. DispatcherServlet就会查询springmvc的配置文件，找HandlerMapping，根据bean的名称查找相应的controller.
4. 找到我的MyController类，执行该类中handleRequestInternal方法。
5. 根据返回的modelAndView在找springmvc配置文件中视图解析器，把viewName和prefix以及suffix做了一个拼接，把拼接的页面展示给客户。

 四、常见的HandlerMapping

　　1 BeanNameUrlHandlerMapping 根据bean标签的名称找到对应的Controller类

　　<!-- 配置一个handlerMapping 默认有一个， 可以不配，默认为name访问 -->
    <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"></bean>
   
    <!-- 注册自己的controller类 -->
    <bean name="/login.do" class="com.zhiyou100.klb.controller.MyController1"></bean>

　　2. SimpleUrlHandlerMapping 根据bean的id查找对应的Controller类

　　<!-- 根据ID查询相应的controller类
        这里包含了ID与URL地址的映射关系    
     -->
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/a.do">my1</prop>
                <prop key="/b.do">my2</prop>
            </props>
        </property>
    </bean>
    
    <bean id="my1" class="com.zhiyou100.klb.controller.MyController1"></bean>
    <bean id="my2" class="com.zhiyou100.klb.controller.MyController2"></bean>

　　3.ControllerClassNameHandlerMapping 根据controller类的名字找到对应的Controller

    <!-- 配置一个handlerMapping，使用类名访问-->
    <bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"></bean>
   
    <!-- 访问时，类中除了controller外其他全部小写，包括controller2 -->
    <bean class="com.zhiyou100.klb.controller.MyController2"></bean>

 

　　4.使用注解来替代配置信息。

1. 额外aop的jar包
2. 在springmvc配置文件中加入如下代码。

　　 <!-- 包扫描：扫描 -->
    <context:component-scan base-package="com.zhiyou100.klb.annotation"></context:component-scan>
    
    <!-- 开启注解驱动 -->
    <mvc:annotation-driven />
    
    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/view/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>

　　3.创建Controller类 

package com.zhiyou100.klb.annotation;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller //等价于<bean class="com.zhiyou100.klb.annotation.MyController" />
public class MyController 
    
    @RequestMapping("/list.do")    //requestMapping:表示的就是你的访问地址
    public ModelAndView list() 
        System.out.println("查询所有");
        ModelAndView mv = new ModelAndView();
        mv.setViewName("login");
        mv.addObject("userName", "查询所有");
        return mv;
    
    
    @RequestMapping("/delete.do")
    public String delete() 
        System.out.println("删除");
        return "login";
    
    
    @RequestMapping("/save.do")
    public String save() 
        System.out.println("保存");
        return "login";