Day22 - Embedded Web Servers

前言

在Java Web的世界裡有好多的Application Server可供選擇，例如WebSphere、Weblogic、Jboss、Tomcat EE、Paraya等等，也有只有Servlet Container的Web Server可供選擇，例如Tomcat、Undertow、Jetty等
。Spring Boot的一大特色之一就是自帶Web Server，提供Tomcat、Undertow、Jetty可供選擇，今日我們來談談Embedded Web Server吧

專案建立

Embedded Web Servers

ServletWebServerFactoryAutoConfiguration

從這個類別自動裝配WebServer

• @EnableConfigurationProperties
  設定檔設定綁定server
• @Import
  引入三個embeded web server，放入三個ServletWebServerFactory
• ServletWebServerFactory中有getWebServer方法提供取得WebServer
  
• ServletWebServerApplicationContext ioc容器啟動時會調用創建調用WebServer

Use Another Web Server

<properties>
    <servlet-api.version>3.1.0</servlet-api.version>
</properties>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <!-- Exclude the Tomcat dependency -->
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<!-- Use Undertow instead -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-undertow</artifactId>
</dependency>

Change the HTTP Port

server:
  port: 9999

Reference

• Embedded Web Servers - Spring Boot doc
• Comparing Embedded Servlet Containers in Spring Boot - Baeldung
• 尚硅谷SpringBoot3零基础教程，springboot入门到实战