Undertow 是红帽公司开发的一款基于 NIO 的高性能 Web 嵌入式服务器
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    1. <dependency>
    2.     <groupId>org.springframework.boot</groupId>
    3.     <artifactId>spring-boot-starter-web</artifactId>
    4.     <exclusions>
    5.         <exclusion>
    6.             <groupId>org.springframework.boot</groupId>
    7.             <artifactId>spring-boot-starter-tomcat</artifactId>
    8.         </exclusion>
    9.     </exclusions></dependency><dependency>
    10.     <groupId>org.springframework.boot</groupId>
    11.     <artifactId>spring-boot-starter-undertow</artifactId>
    12.   </dependency>