Recently, I come across a situation where both maven-jetty plugin & embedded jetty server need to packed along with web-application. I have already written a blog on incorporating maven-jetty plugin in the web app
here, hence will not be discussing here again. I will describe here about package of embedded jetty server with in web application below.
Firstly, why do we require to include embedded jetty?
1. Easy deployment, java -jar <web-app>.jar, once you build the artifact, it's ready for deployment without any hassle configurations/deployment procedures, etc
2. No requirement of application server.
Let's go through the following steps to include jetty server within web app.
1. Create a JettyServer class
package com.sateesh.application.server;
import org.eclipse.jetty.server.Connector;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.jetty.util.thread.QueuedThreadPool;
import org.eclipse.jetty.webapp.WebAppContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.DispatcherServlet;
import java.io.IOException;
public class JettyServer {
private static final Logger logger = LoggerFactory.getLogger(JettyServer.class);
private final String WEB_APP_DIR = "src/main/webapp";
private final String WEB_XML_PATH = "src/main/webapp/WEB-INF/web.xml";
private static final String MVC_SERVLET_NAME = "dispatcher";
private static final String JSP_SERVLET_NAME = "jspServlet";
private static final String DEFAULT_PORT = "8080";
private static final String DEFAULT_CONTEXT_PATH = "/";
public static void main(String[] args) throws Exception{
JettyServer jettyServer = new JettyServer();
jettyServer.start();
}
private JettyServer() {
// none can instantiate this class
}
private void start() throws Exception{
try {
QueuedThreadPool threadPool = new QueuedThreadPool(512);
final Server server = new Server(threadPool);
server.setStopAtShutdown(true);
server.setStopTimeout(5000);
ServerConnector connector = new ServerConnector(server);
connector.setPort(getPort());
connector.setIdleTimeout(30000);
server.setConnectors(new Connector[]{connector});
server.setHandler(getServletContextHandler());
server.start();
server.join();
logger.info("Embedded Jetty Server is started!");
} catch (Exception e) {
logger.error("Exception occurred while starting the jetty server ", e);
}
}
private WebAppContext getServletContextHandler() throws IOException {
final WebAppContext contextHandler = new WebAppContext();
contextHandler.setContextPath(getContextPath());
contextHandler.setWar(WEB_APP_DIR);
contextHandler.setDefaultsDescriptor(WEB_XML_PATH);
ServletHolder jspServletHolder = new ServletHolder("jspServlet", new org.apache.jasper.servlet.JspServlet());
// jsp servelet is required to parse the jsp passed by the spring-mvc
contextHandler.addServlet(jspServletHolder, "*.jsp");
return contextHandler;
}
/**
* Consider default port as "8080" until unless not passed using java args
**/ private int getPort() {
Integer port = Integer.parseInt(System.getProperty("jetty.port"));
if (port == null || port == 0) {
port = Integer.parseInt(DEFAULT_PORT);
}
return port;
}
/**
* Consider default context path as "/" until unless not passed using java args
**/
private String getContextPath() {
String contextPath = System.getProperty("jetty.contextPath");
if (contextPath == null || contextPath.equals("")) {
contextPath = DEFAULT_CONTEXT_PATH;
}
return contextPath;
}
}
2. Contents of web.xml (default descriptor executed by JettyServer).
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="YourWebAppID"
version="2.5">
<display-name>Web App Server</display-name>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
classpath:META-INF/spring/application-context.xml
</param-value>
</context-param>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:dispatcher-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/api/*</url-pattern>
</servlet-mapping>
</web-app>
3. Contents of application-context.xml & dispatcher-servlet.xml files
application-context.xml --- is spring descriptor file.
dispatcher-servlet.xml --- is servlet dispatcher file, which will scan @Controller annotated packages.
4. Package structure of the project
--- src
--- main
--- java
--- com.sateesh.application.server
--- resources
--- META-INF
--- spring
--- application-context.xml
--- dispatcher-servlet.xml
--- logback.xml
--- webapp
--- views
--- ***.jsp
--- web.xml
5. below plugin needs to be added in pom.xml
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.3</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<filters>
<filter>
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
<createDependencyReducedPom>true</createDependencyReducedPom>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>com.sateesh.application.server.JettyServer</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
6. add below dependencies in pom.xml
<properties>
<jetty.server.scope>compile</jetty.server.scope>
<jetty.version>9.1.2.v20140210</jetty.version>
</properties>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
<version>${jetty.version}</version>
<scope>${jetty.server.scope}</scope>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-webapp</artifactId>
<version>${jetty.version}</version>
<scope>${jetty.server.scope}</scope>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlet</artifactId>
<version>${jetty.version}</version>
<scope>${jetty.server.scope}</scope>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-jsp</artifactId>
<version>${jetty.version}</version>
<scope>${jetty.server.scope}</scope>
</dependency>
7. You are almost there.. now run the web application now.
build the project (default package is jar in maven):
mvn clean package
run the webapp:
java -jar target/webapp.jar
PS: we can also create embedded jetty server with in web-app without web.xml file also.
