5. Replacing tomcat with jetty

By default when we run spring boot application, it runs a tomcat server. I have personally found tomcat too heavyweight and I prefer to use Jetty for writing a webservices backend.

2018-12-19 10:54:08.403  INFO 16029 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)

2018-12-19 10:54:08.424  INFO 16029 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]

2018-12-19 10:54:08.424  INFO 16029 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/9.0.12

To replace tomcat with Jetty, we need to make a couple of changes.  The first step is to add Jetty dependencies in the pom.xml.

  
  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-jpa</artifactId>
  </dependency>
  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-jetty</artifactId>
  </dependency>
  <dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-deploy</artifactId>
  </dependency>
  <dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-rewrite</artifactId>
  </dependency>
  <dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-util</artifactId>
  </dependency>

Since springframework boot bom automatically includes a dependency on tomcat in spring-boot-starter-web, we specifically need to exclude it. So we change

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
  </dependency>

to

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
   <exclusions>
    <exclusion>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-tomcat</artifactId>
    </exclusion>
   </exclusions>
  </dependency>

	package in.springframework.blog.tutorials;
	import org.apache.logging.log4j.LoggingException;
	import org.eclipse.jetty.server.*;
	import org.eclipse.jetty.server.handler.HandlerCollection;
	import org.eclipse.jetty.server.handler.RequestLogHandler;
	import org.eclipse.jetty.util.thread.QueuedThreadPool;
	import org.springframework.beans.factory.annotation.Value;
	import org.springframework.boot.web.embedded.jetty.JettyServerCustomizer;
	import org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory;
	import org.springframework.boot.web.server.WebServerFactoryCustomizer;
	import org.springframework.context.annotation.Bean;
	import org.springframework.context.annotation.Configuration;
	import java.io.File;
	/**
	* Created by vinay on 2/3/16.
	*/
	@Configuration
	public class HelloWorldJettyCustomizer {
	@Bean
	WebServerFactoryCustomizer<JettyServletWebServerFactory> containerCustomizer(
	@Value("${server.port:8081}") final int port,
	@Value("${jetty.acceptqueuesize:5000}") final String acceptQueueSize,
	@Value("${jetty.threadPool.maxThreads:2000}") final String maxThreads,
	@Value("${jetty.threadPool.minThreads:8}") final String minThreads,
	@Value("${jetty.threadPool.idleTimeout:60000}") final String idleTimeout,
	@Value("${logging.path:/tmp}") final String loggingPath)
	throws Exception {
	// This is boiler plate code to setup https on embedded Tomcat
	// with Spring Boot:
	return container -> {
	container.addServerCustomizers((JettyServerCustomizer) server -> {
	// Enable logs
	File logFile = new File(loggingPath + "/product-yyyy_mm_dd.access.log");
	String logFilename = logFile.getAbsolutePath();
	if (!logFile.getParentFile().exists() && !logFile.getParentFile().mkdirs()) {
	throw new LoggingException(String.format("%s could not be created.", logFile.getParentFile().getAbsolutePath()));
	}
	NCSARequestLog requestLog = new NCSARequestLog(logFilename);
	requestLog.setAppend(true);
	requestLog.setExtended(false);
	requestLog.setLogTimeZone("UTC");
	RequestLogHandler rlh = new RequestLogHandler();
	rlh.setRequestLog(requestLog);
	Handler[] handlers = server.getHandlers();
	if (handlers == null || handlers.length == 0) {
	server.setHandler(rlh);
	}
	else {
	HandlerCollection handlerCollection = new HandlerCollection();
	for (int i = 0; i < handlers.length; ++i) {
	handlerCollection.addHandler(handlers[i]);
	}
	handlerCollection.addHandler(rlh);
	server.setHandler(handlerCollection);
	}
	// Tweak the connection pool used by Jetty to handle incoming HTTP connections
	final QueuedThreadPool threadPool = server.getBean(QueuedThreadPool.class);
	threadPool.setMaxThreads(Integer.valueOf(maxThreads));
	threadPool.setMinThreads(Integer.valueOf(minThreads));
	threadPool.setIdleTimeout(Integer.valueOf(idleTimeout));
	threadPool.setName("Jetty-Threadpool");
	for (Connector connector : server.getConnectors()) {
	if (connector instanceof ServerConnector) {
	ServerConnector serverConnector = (ServerConnector)connector;
	serverConnector.setPort(port);
	serverConnector.setAcceptQueueSize(Integer.valueOf(acceptQueueSize));
	serverConnector.setIdleTimeout(Integer.valueOf(idleTimeout));
	HttpConnectionFactory connectionFactory = connector.getConnectionFactory(HttpConnectionFactory.class);
	connectionFactory.getHttpConfiguration().setSendServerVersion(false);
	}
	}
	});
	};
	}
	}

view raw HelloWorldJettyCustomizer.java hosted with ❤ by GitHub

The next step is to add a customizer for jetty which will allow us to set some parameters related to Jetty.
As we can see the customizer uses a set of variables that we can override in application.properties file to modify the behavior of the server.

2018-12-19 11:06:44.577  INFO 16219 --- [           main] o.e.jetty.server.AbstractConnector       : Started ServerConnector@42ebece0{HTTP/1.1,[http/1.1]}{0.0.0.0:8081}
2018-12-19 11:06:44.580  INFO 16219 --- [           main] o.s.b.web.embedded.jetty.JettyWebServer  : Jetty started on port(s) 8081 (http/1.1) with context path ''

Now the logs clearly show that in place of tomcat, it is running jetty.