第一种SpringInitConfig extends AbstractAnnotationConfigDispatcherServletInitializer

看第一种配置

package com.xxx.config;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class SpringInitConfig extends AbstractAnnotationConfigDispatcherServletInitializer {


    /**
     * //加载spring容器配置
     * 加载根配置类
     * @return
     */
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{RootConfig.class};
    }

    /**
     * 加载springmvc配置类(web容器配置类)
     * @return
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfig.class};
    }

    /**
     * 设置哪些请求归属springMVC处理
     * 配置SpringMVC的映射路径(访问路径)
     * 配置SpringMVC拦截哪些请求(哪些请求应该交给DispatcherServlet来处理)
     * @return
     * return new String[]{"/"}; 拦截所有请求，但不拦截jsp页面 (相当于自动进入SpringMVC里面)
     * return new String[]{"/*"}; 表示拦截所有请求 (也相当于自动进入SpringMVC里面)
     * return new String[0];     html和jsp两个页面都可以访问到
     */

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/*"};
    }
}

WebConfig代码

package com.xxx.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * SpringMVC配置类(管理的是配置类)
 *  -管理控制器(Servlet)
 *  @EnableWebMvc:开启SpringMVC注解，开启后可以使用SpringMVC提供的相关注解
 */
@Configuration
@ComponentScan("com.xxx.controller")
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
    //放行静态资源
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

}

第二种ServletContainersInitConfig extends AbstractDispatcherServletInitializer

第二种还没配根(Spring)容器

package com.xxx.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的配置
public class ServletContainersInitConfig extends AbstractDispatcherServletInitializer {

    //加载springMVC容器配置
    @Override
    protected WebApplicationContext createServletApplicationContext() {
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        ctx.register(SpringMvcConfig.class);
        return ctx;
    }

    //设置哪些请求归属springMVC处理
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    //加载spring容器配置
    @Override
    protected WebApplicationContext createRootApplicationContext() {
        return null;
    }

}

SpringMvcConfig代码

package com.xxx.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
//3.创建springmvc的配置文件，加载controller对应的bean
@Configuration
@ComponentScan("com.xxx.controller")
public class SpringMvcConfig {
}