java config, web.xml -> java config(web.xml을 java config에 넣다.)

예제 hellospring2 -> hellospring3 

기본 메이븐 프로젝트 생성 및 라이브러리, pom 설정 완료 후

src/main/java에

com.douzone.hellospring.initializer 패키지 추가

안에 HelloSpringWebApplicationInitializer 클래스 생성

HelloSpringWebApplicationInitializer 클래스는 web.xml의 역할을 대신하는 기능들을 가진다.

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" version="3.1">
    <display-name>hellospring</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
 
    <!-- Front Controller -->
    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextClass</param-name>
            <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
        </init-param>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>com.douzone.hellospring.config.WebConfig</param-value>
        </init-param>
        
        <load-on-startup>1</load-on-startup>
        <!-- 톰캣이 뜰때 이 컨테이너가 만들어짐 -->
    </servlet>
 
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
 
</web-app>

HelloSpringWebApplicationInitializer.java

package com.douzone.hellospring.initializer;
 
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
 
import com.douzone.hellospring.config.WebConfig;
 
public class HelloSpringWebApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
 
    @Override
    protected String[] getServletMappings() {
        return new String[] {"/"};
    }
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] {WebConfig.class};
    }
 
 
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }
 
}

1. servlet-mapping 옮기기

web.xml에서

<servlet-mapping>

    <servlet-name>spring</servlet-name>

    <url-pattern>/</url-pattern>

</servlet-mapping>

servlet-mapping 부분을 

HelloSpringWebApplicationInitializer에서

 @Override

    protected String[] getServletMappings() {

        return new String[] {"/"};

    }

로 처리해줌

2. servlet 옮기기

web.xml에서

<!-- Front Controller -->

    <servlet>

        <servlet-name>spring</servlet-name>

        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

        <init-param>

            <param-name>contextClass</param-name>

            <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>

        </init-param>

        <init-param>

            <param-name>contextConfigLocation</param-name>

            <param-value>com.douzone.hellospring.config.WebConfig</param-value>

        </init-param>

        <load-on-startup>1</load-on-startup>

        <!-- 톰캣이 뜰때 이 컨테이너가 만들어짐 -->

    </servlet>

servlet 부분을

HelloSpringWebApplicationInitializer에서

@Override

    protected Class<?>[] getServletConfigClasses() {

        return new Class<?>[] {WebConfig.class};

    }

로 처리해줌

3. welcome-file-list부분은 

<welcome-file-list>

        <welcome-file>index.html</welcome-file>

        <welcome-file>index.htm</welcome-file>

        <welcome-file>index.jsp</welcome-file>

        <welcome-file>default.html</welcome-file>

        <welcome-file>default.htm</welcome-file>

        <welcome-file>default.jsp</welcome-file>

    </welcome-file-list>

웹 요청 시 지정되어 있는 리소스 call

즉, http://localhost:8080 요청 시 index.jsp의 content를 보여주는데

이미 main에서 잡아주기때문에 

이 과정을 거치면 web.xml이 없어도 돌아간다.