SpringMVC-初识SpringMVC

SpringMVC的开发步骤

• 导入SpringMVC的相关坐标
• 配置Servlet
• 编写Controller
• 将 Controller 使用注解 @Controller 配置到容器当中
• 配置组件扫描到spring-mvc.xml
• 执行测试
  
  

SpringMVC的快速入门

创建一个名为study_Spring03的简单web项目

导入SpringMVC的相关坐标

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>study_Spring03</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>study_Spring03 Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.17</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.3.17</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>5.3.17</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.17</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.2</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>javax.servlet.jsp-api</artifactId>
      <version>2.3.3</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>study_Spring03</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

配置（前端控制器、组件扫描）

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>

  <!--全局配置-->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:appContext.xml</param-value>
  </context-param>

  <!--配置前端控制器-->
  <servlet>
    <servlet-name>DispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--扩展配置方式-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring-mvc.xml</param-value>
    </init-param>
    <!--前端控制器初始化早于服务器启动-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <!--映射-->
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <!--匹配的可以是/xxx或.html、.js、.css。但不能是.jsp-->
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

appContext.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

spring-mvc.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"
       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
">
    <!--组件扫描-->
    <context:component-scan base-package="com.sjj.controller" />
</beans>

编写Controller

跳转的页面success.jsp需要自己准备

package com.sjj.controller;

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

// 注释web类
@Controller
public class UserController {
    // 请求映射方法
    @RequestMapping("/success")
    public String print_test(){
        System.out.println("Controller print_test running……");
        // 跳转试图
        return "success.jsp";
    }
}

测试

配置tomcat，将项目以工件的形式添加到服务器启动时部署，并且将应用程序上下文设置为 /
启动项目 访问 localhost:8080/success

最后看一下项目结构

非常的简单

SpringMVC的组件解析

SpringMVC的执行流程

1. 浏览器发起请求找到前端控制器DispatcherServlet

2. 前端控制器向处理查询器HandlerMapping请求查询Handler

3. 处理器返回处理器执行链HandlerExecutionChain

4. 前端控制器向处理适配器HandlerAdaptor请求执行Handler

5. 处理适配器请求处理器Handler

6. 处理器响应处理适配器

7. 处理适配器向前端控制器返回ModelAndView

8. 前端控制器请求视图解析器ViewResolver

9. 视图解析器返回视图View对象

10. 前端控制器渲染视图

SpringMVC的执行注解解析

@RequestMapping

作用：用于建立请求URL和请求处理方法之间的对应关系
位置：

• 类上：请求URL的第一级访问目录。此处不写的话，就相当于应用的根目录。
• 方法上：请求URL的第二级目录，与在类上使用的RequestMapping标注的第一级目录组成虚拟访问路径
  属性：
• value：用于指定请求URL
  -method：用于指定请求方式
• params：用于指定请求参数条件。