4. springmvc底层原理2

• Spring mvc 是子容器
• Spring 是 父容器

===================================================================

public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] { RootConfig.class };
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] { App1Config.class };
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] { "/app1/*" };
    }
}

刚才我们是写个类实现人家的接口，现在我们写个类继承人家的接口

===================================================================

===================================================================

• 继承AbstractAnnotationConfigDispatcherServletInitializer
  

package com.min.demo1;

import com.min.config.App1Config;
import com.min.config.RootConfig;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public  class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] { RootConfig.class };
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] { App1Config.class };
    }

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

===================================================================

• 编写配置类
  **App1Config **

package com.min.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(value = "com.min.controller")
public class App1Config {
}

**RootConfig **

package com.min.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan(value = "com.min.service")
public class RootConfig {

}

===================================================================

• 编写Controller

package com.min.controller;

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

@Controller
public class TestController {

    @RequestMapping(value = "/hello2.*")
    @ResponseBody
    public String hello(){
        return "hello";
    }
}

• 访问hello2.do

===================================================================

===================================================================

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addFormatters(FormatterRegistry registry) {
        // ...
    }
}

===================================================================
默认实现方法

===================================================================

• 添加跳转jsp视图（配置视图解析器）

package com.min.config;

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

@Configuration
@ComponentScan(value = "com.min.controller")
@EnableWebMvc
public class App1Config implements WebMvcConfigurer {

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        /*
         *  public UrlBasedViewResolverRegistration jsp() {
         *     return this.jsp("/WEB-INF/", ".jsp");
         *  }
         */
        //registry.jsp();

        registry.jsp("/WEB-INF/jsps/",".jsp");
    }
}

• 编写controlelr

package com.min.controller;

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

@Controller
public class TestController {

    @RequestMapping(value = "/hello.do")
    @ResponseBody
    public String hello(){
        return "hello";
    }

    @RequestMapping(value = "/hello2.do")
    public String hello2(){
        return "a";
    }
}

• /web-inf/jsps/下编写a.jsp页面

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2020/6/5
  Time: 9:20
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1>我是JSP页面视图</h1>
</body>
</html>

• App1Config 还可以配置拦截器和视图解析器