SSM框架学习之SpringMVC浅谈

什么是SpringMVC

 百度：Spring MVC属于SpringFrameWork的后续产品，已经融合在Spring Web Flow里面。Spring 框架提供了构建 Web 应用程序的全功能 MVC 模块。简单来说，SpringMVC就是Spring在基于MVC思想的基础上研发出的框架。

SpringMVC流程

 MVC思想：把页面/浏览器发来的请求通过Controller（控制器）调用Model（数据模型和业务模型）进行数据封装和业务处理，然后再把处理后的结果通过View（视图）展现出来。

SpringMVC的流程：

1. 用户发送请求到DispatcherServlet 控制器

2. DispatcherServlet 控制器根据请求路径到HandlerMapping映射器查询具体的handler处理器

3. HandlerMapping映射器根据用户请求查找与之对应的HandlerExecutionChain执行链再回传给DispatcherServlet控制器

4. DispatcherServlet控制器根据handler具体的实现方式调用HandlerAdapter适配器

5. HandlerAdapter适配器调用具体的handler处理器处理业务并返回ModelAndView到DispatcherServlet控制器

6. DispatcherServlet控制器将ModelAndView专递到ViewResolver视图解析器

7. ViewResolver视图解析器 返回具体的视图到DispatcherServlet控制器

8. DispatcherServlet控制器渲染视图后响应给用户

SpringMVC配置文件

 配置文件(一般命名：springmvc-servlet.xml)的配置流程就是跟随着SpringMVC的流程进行配置，DispatcherServlet 是“springframework”下的依赖，不用配置，Model（handler）和View是自己代码实现，所以也不用配置，因此只用配置HandlerMapping（映射器）、HandlerAdapter（适配器）、ViewResolver（视图解析器）。又因为目前开发一般都会用到“注解”，就需要在配置文件中添加注解驱动<mvc:annotation-driven />，可以免去HandlerMapping（映射器）、HandlerAdapter（适配器）。

补充：<mvc:annotation-driven />的作用：https://www.cnblogs.com/afeng2010/p/10133797.html

DispatcherServlet 的父类是FrameworkServlet，点进去看到一段注释规定了配置文件的位置和命名规则：默认读取/WEB-INF/{servlet-name}-servlet.xml这个配置文件，一般默认为：springmvc-servlet.xml

 

 springmvc-servlet.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
 4        xmlns:context="http://www.springframework.org/schema/context"
 5        xmlns:mvc="http://www.springframework.org/schema/mvc"
 6        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 7         http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
 8         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
 9     <!-- 配置注解驱动，替代推荐使用的映射器以及适配器，json转换器 -->
10     <mvc:annotation-driven />
11     <!-- 开启注解扫描 -->
12     <context:component-scan base-package="com.demo.controller"></context:component-scan>
13     <!-- 配置视图解析器 -->
14     <!-- Example: prefix="/WEB-INF/jsp/", suffix=".jsp", viewname="test" -> "/WEB-INF/jsp/test.jsp"  -->
15     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
16         <property name="prefix" value="/WEB-INF/views/"></property>
17         <property name="suffix" value=".jsp"></property>
18     </bean>
19 </beans>

项目demo：

项目结构：

 pom.xml:

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5   <modelVersion>4.0.0</modelVersion>
 6 
 7   <groupId>com.demo.springmvc</groupId>
 8   <artifactId>springmvc</artifactId>
 9   <version>1.0-SNAPSHOT</version>
10   <packaging>war</packaging>
11 
12   <name>springmvc Maven Webapp</name>
13   <!-- FIXME change it to the project's website -->
14   <url>http://www.example.com</url>
15 
16   <properties>
17     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
18     <maven.compiler.source>1.8</maven.compiler.source>
19     <maven.compiler.target>1.8</maven.compiler.target>
20   </properties>
21 
22   <dependencies>
23     <dependency>
24       <groupId>org.springframework</groupId>
25       <artifactId>spring-webmvc</artifactId>
26       <version>5.1.7.RELEASE</version>
27     </dependency>
28     <dependency>
29       <groupId>org.slf4j</groupId>
30       <artifactId>slf4j-log4j12</artifactId>
31       <version>1.7.12</version>
32     </dependency>
33     <!-- JSP相关 -->
34     <dependency>
35       <groupId>jstl</groupId>
36       <artifactId>jstl</artifactId>
37       <version>1.2</version>
38     </dependency>
39     <dependency>
40       <groupId>javax.servlet</groupId>
41       <artifactId>servlet-api</artifactId>
42       <version>2.5</version>
43     </dependency>
44     <dependency>
45       <groupId>javax.servlet</groupId>
46       <artifactId>jsp-api</artifactId>
47       <version>RELEASE</version>
48     </dependency>
49     <dependency>
50       <groupId>junit</groupId>
51       <artifactId>junit</artifactId>
52       <version>4.11</version>
53     </dependency>
54   </dependencies>
55 
56   <build>
57     <finalName>springmvc</finalName>
58     <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
59       <plugins>
60         <plugin>
61           <artifactId>maven-clean-plugin</artifactId>
62           <version>3.1.0</version>
63         </plugin>
64         <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
65         <plugin>
66           <artifactId>maven-resources-plugin</artifactId>
67           <version>3.0.2</version>
68         </plugin>
69         <plugin>
70           <artifactId>maven-compiler-plugin</artifactId>
71           <version>3.8.0</version>
72         </plugin>
73         <plugin>
74           <artifactId>maven-surefire-plugin</artifactId>
75           <version>2.22.1</version>
76         </plugin>
77         <plugin>
78           <artifactId>maven-war-plugin</artifactId>
79           <version>3.2.2</version>
80         </plugin>
81         <plugin>
82           <artifactId>maven-install-plugin</artifactId>
83           <version>2.5.2</version>
84         </plugin>
85         <plugin>
86           <artifactId>maven-deploy-plugin</artifactId>
87           <version>2.8.2</version>
88         </plugin>
89       </plugins>
90     </pluginManagement>
91   </build>
92 </project>
Pom.xml文件

Web.xml:

 1 <!DOCTYPE web-app PUBLIC
 2  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 3  "http://java.sun.com/dtd/web-app_2_3.dtd" >
 4 
 5 <web-app>
 6   <display-name>Archetype Created Web Application</display-name>
 7 
 8   <servlet>
 9     <servlet-name>springmvc</servlet-name>
10     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
11     <load-on-startup>1</load-on-startup>
12   </servlet>
13   <servlet-mapping>
14     <servlet-name>springmvc</servlet-name>
15     <!--
16         /*：拦截所有请求，包括jsp
17         / ：拦截所有请求，不包含jsp
18         *.do,*.action
19      -->
20     <url-pattern>*.do</url-pattern>
21   </servlet-mapping>
22   <welcome-file-list>
23     <welcome-file>index.html</welcome-file>
24     <welcome-file>index.htm</welcome-file>
25     <welcome-file>index.jsp</welcome-file>
26     <welcome-file>default.html</welcome-file>
27     <welcome-file>default.htm</welcome-file>
28     <welcome-file>default.jsp</welcome-file>
29   </welcome-file-list>
30 </web-app>
Web.xml

index.jsp:

 1 <%@ page language="java" contentType="text/html; charset=utf-8"
 2          pageEncoding="utf-8" %>
 3 <html>
 4 <head>
 5     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 6 </head>
 7 <body>
 8 <h2>Hello World!</h2>
 9 <form action="/hello.do">
10     <button type="submit" style="height: auto ;  auto">跳转</button>
11 </form>
12 </body>
13 </html>
index.jsp

hello.jsp:

 1 <%@ page language="java" contentType="text/html; charset=utf-8" isELIgnored="false"
 2          pageEncoding="utf-8"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 7     <title>Insert title here</title>
 8 </head>
 9 <body>
10 <!-- <span style="font-size:30px; color:red;">第一个springmvc程序</span> -->
11 <span style="font-size:30px; color:red;">${msg }</span>
12 </body>
13 </html>
Hello.jsp

springmvc-servlet.xml:

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
 4        xmlns:context="http://www.springframework.org/schema/context"
 5        xmlns:mvc="http://www.springframework.org/schema/mvc"
 6        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 7         http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
 8         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
 9     <!-- 配置注解驱动，替代推荐使用的映射器以及适配器，json转换器 -->
10     <mvc:annotation-driven />
11     <!-- 开启注解扫描 -->
12     <context:component-scan base-package="com.demo.controller"></context:component-scan>
13     <!-- 配置视图解析器 -->
14     <!-- Example: prefix="/WEB-INF/jsp/", suffix=".jsp", viewname="test" -> "/WEB-INF/jsp/test.jsp"  -->
15     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
16         <property name="prefix" value="/WEB-INF/views/"></property>
17         <property name="suffix" value=".jsp"></property>
18     </bean>
19 </beans>
springmvc-servlet.xml

mycontroller:

 1 @Controller
 2 public class mycontroller {
 3     @RequestMapping("hello")
 4     public ModelAndView test() {
 5         ModelAndView mv = new ModelAndView();
 6         //设置返回页面的名称
 7         mv.setViewName("hello");
 8         //设置返回信息
 9         mv.addObject("msg", "HelloWorld!");
10         return mv;
11     }
12 }
MyController

SpringMVC注解

  • Controller：表示该类为一个处理器,相当于 mycontroller implements Controller
  • RequestMapping(value="hello"),配置方法的对应的url , 默认的url后缀和<url-pattern>*.do</url-pattern> 一致
  • GetMapping：相当于RequestMapping（method = RequestMethod.GET）
  • PostMapping：相当于RequestMapping（method = RequestMethod.POST）
  • PutMapping：相当于RequestMapping（method = RequestMethod.PUT）
  • DeleteMapping：相当于RequestMapping（method = RequestMethod.DELETE）

 

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原文地址：https://www.cnblogs.com/Bernard94/p/14093718.html