SpringMVC入门案例

雨点打透心脏的1/2处 2024-05-23 14:13 52阅读 0赞

### 一、基础环境配置 ###

1、新建空maven项目：  
![在这里插入图片描述][5f556dfdfc814c7cba31e4480952f619.png]  
2、添加web框架框架支持  
![在这里插入图片描述][6fd8d071327f4729bdf00c73c26ceafe.png]  
3、导包

<?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>SpringMVC</artifactId>
        <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.10.RELEASE</version>
        </dependency>
    </dependencies>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.tomcat.maven</groupId>
                    <artifactId>tomcat7-maven-plugin</artifactId>
                    <version>2.1</version>
                    <configuration>
                        <port>80</port>
                        <path>/</path>
                        <uriEncoding>UTF-8</uriEncoding>
                        <ignorePackaging>true</ignorePackaging>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </project>

### 二、基础代码框架 ###

3、使用@Controller定义Bean

4、提供一个处理请求并响应的方法

package com.bone.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    @Controller     //定义bean
    public class demo {
        
        @RequestMapping("/demo1")       //访问路径
        @ResponseBody       //设置当前操作的返回值类型
        public String demo1(){
        
            System.out.println("demo1 is running!!!!");
            return "{'info':'springmvc'}";
        }
    
    }

5、创建springMVC配置文件——加载bean(@controller)

package com.bone.config;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    @ComponentScan("com.bone.controller")       //加载controller 对应的bean
    public class SpringMvcConfig {
        
    }

5、启动tomcat加载配置文件

package com.bone.config;
    
    import org.springframework.web.context.WebApplicationContext;
    import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
    import org.springframework.web.servlet.support.AbstractDispatcherServletInitializer;
    
    //4、定义一个servlet容器启动的配置类，在里面加载spring配置
    public class ServletContainerConfig extends AbstractDispatcherServletInitializer {
        
        //加载springmvc容器配置
        @Override
        protected WebApplicationContext createServletApplicationContext() {
        
            AnnotationConfigWebApplicationContext acwc = new AnnotationConfigWebApplicationContext();
            acwc.register(SpringMvcConfig.class);
            return acwc;
        }
        //设置哪些请求归属springmvc处理
        @Override
        protected String[] getServletMappings() {
        
    
            return new String[]{
        "/"};       //所有请求归springmvc处理
        }
        //加载spring容器的配置
        protected WebApplicationContext createRootApplicationContext() {
        
            return null;
        }
    }

6、运行  
![在这里插入图片描述][eeb834b6c0e041a3b4e87d994f95fa62.png]  
![在这里插入图片描述][714884e1d84f4a5598d37777bc1f7340.png]  
三、工作流程分析  
1、服务器启动，执行ServletContainerConfig类，初始化web容器。  
2，执行createServletApplicationContext方法，创建WebApplicationContext对象加载SpringMvcConfig。  
3 、执行配置类中的@ComponentScan加载对应的bean。  
4 、加载demo，每个@RequestMapping的名称对应一个具体的方法。  
5、执行getServletMappings方法，定义所有的请求都通过SpringMVC。

1、发送请求localhost/demo1  
2、web容器发现所有请求都经过SpringMVC，将请求交给SpringMVC处理  
3、解析请求路径/demo1  
4、由/demo1匹配执行对应的方法demo1()  
5、执行demo1()  
6、检测到有@ResponseBody直接将demo1()方法的返回值作为响应体返回给请求方

[5f556dfdfc814c7cba31e4480952f619.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/05/23/733c89427f944c0f9084092fecf58262.png
[6fd8d071327f4729bdf00c73c26ceafe.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/05/23/b610a898b3904b1699f417f0291d497a.png
[eeb834b6c0e041a3b4e87d994f95fa62.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/05/23/c46f8703b14c4867a9198069d56f9713.png
[714884e1d84f4a5598d37777bc1f7340.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/05/23/bb626db3d4544896bfe066ad0146abf3.png