How to create a Web Application Project with Java/Maven/Jetty or Tomcat

In this article, we create a simple web application with the Maven Archetype plugin. We’ll run this web application in a Servlet container named Jetty, add some dependencies, write simple Servlets, and generate a WAR file. At the end of this article, you will also be able to deploy the service in Tomcat.

System requirements

• Java SE Development Kit 8
• Maven 3.3.3

Creating the Web Service Step by Step

This section explains how to create this simple web project from an EMPTY folder.

Creating the Simple Web Project

To create your web application

$ mvn archetype:generate -DgroupId=com.pengyifan.simpleweb \
      -DartifactId=simple-webapp \
      -Dpackage=com.pengyifan.simpleweb \
      -DarchetypeArtifactId=maven-archetype-webapp \
      -Dversion=1.0-SNAPSHOT \
      -DinteractiveMode=false

...
[INFO] BUILD SUCCESS

Once the Maven Archetype plugin creates the project, change the directory into the simple-webapp directory and take a look at the pom.xml. You should see the

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.pengyifan.simpleweb</groupId> <artifactId>simple-webapp</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>simple-webapp Maven Webapp</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> </dependencies> <build> <finalName>simple-webapp</finalName> </build> </project> read more

To begin with this story, let’s first have a look at how to creat a List from Stream in Java

List<String> sublist = list
  .stream()
  .filter(...)
  .collect(Collectors.toList());

This works perfectly fine but what if we want the list to be immutable? We could do this

List<String> immutableSubList = Collections.unmodifiableList(sublist);

or if we would like to use Guava ImmutableList, we could do

ImmutableList<String> immutableSubList = ImmutableList.copyOf(sublist);

However this is a bit awkward to use since the list will be copied one more time. If we want to do this in a lot of places throughout the code base, it is not fluid. Instead, what we want is

ImmutableList<String> sublist = list
  .stream()
  .filter(...)
  .collect(ImmutableCollectors.toList());

This post will discuss how to create the Collector of ImmutableList.

Collector

To create a Collector, we will use the static method of.

public static<t, A, R> Collector<T, A, R> of( Supplier<A> supplier, BiConsumer<A, T> accumulator, BinaryOperator<A> combiner, Function<A, R> finisher, Characteristics... characteristics); read more