Complete tutorial of creating basic web service with Jersey.

Configuration

Java Compilation:
Java Runtime:
Web Server:
Maven:

Java Compilation:
Java Runtime:
Web Server:
Gradle:

JDK 11.0.12
JRE HotSpot 11.0.12
Tomcat 9.0.58
Maven 3.8.4

JDK 11.0.12
JRE HotSpot 11.0.12
Tomcat 9.0.58
Gradle 7.4.2

To learn more about using Injection in Jersey, please visit

To learn more about using Message Body Reader and Writer in Jersey, please visit

To learn more about using Container Filter in Jersey, please visit

Create the following folder structure:

folder structure of Create first web service with Jersey

pom.xml: (if using Gradle, replace pom.xml with build.gradle)


<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>net.maxjava</groupId>
    <artifactId>FirstJerseyWebService</artifactId>
    <version>1.0</version>
    <packaging>war</packaging>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet-core</artifactId>
            <version>2.29.1</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.inject</groupId>
            <artifactId>jersey-hk2</artifactId>
            <version>2.29.1</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>


plugins {
    id 'java'
    id 'war'
}

sourceCompatibility = 11
targetCompatibility = 11

group 'net.maxjava'
version '1.0'

repositories {
    mavenCentral()
}

dependencies {
    implementation group: 'org.glassfish.jersey.containers', name: 'jersey-container-servlet-core', version: '2.29.1'
    implementation group: 'org.glassfish.jersey.inject', name: 'jersey-hk2', version: '2.29.1'
}

Some notes about pom.xml:

jersey-container-servlet-core and jersey-hk2 is needed for using Jersey as servlet
maven-compiler-plugin is for compiling the code using source version 11 and target version 11
A war artifact will be created for deployment to servlet containers

Some notes about gradle.build:

jersey-container-servlet-core and jersey-hk2 is needed for using Jersey as servlet
targetCompatibility is used to configure compilation with source version 11 and target version 11
A war artifact will be created for deployment to servlet containers

web.xml:


<web-app>
    <display-name>First Jersey Web Service</display-name>
    <servlet>
        <servlet-name>FirstJerseyWebService</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>javax.ws.rs.Application</param-name>
            <param-value>application.MyApplication</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>FirstJerseyWebService</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
</web-app>

MyApplication.java:


package application;

import org.glassfish.jersey.server.ResourceConfig;
import resource.MyResource;

public class MyApplication extends ResourceConfig {

    public MyApplication() {

        register(MyResource.class);
    }
}

Some notes about MyApplication.java:

This is main configuration class and has to be specified in web.xml
In the constructor, register the resource classes, which are annotated with JAX-RS for web services

MyResource.java:


package resource;

import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.Calendar;

@Path("/myapp")
public class MyResource {

    @GET
    @Path("/currentTime")
    @Produces(MediaType.TEXT_PLAIN)
    public Response getCurrentTime() {
        return Response.ok("now: " + Calendar.getInstance().getTime().toString()).status(Response.Status.OK).build();
    }
}

Some notes about MyResource.java:

The @Path annotation on the class plus @Path annotation on the method will compose the relative path of the web service
The @GET annotation define the method as GET for the web service
The @Produce annotation define content-type of the response

Sample output:


curl --request GET '<CONTEXT_PATH>/myapp/currentTime'

Response:


now: Mon Sep 19 19:11:13 PDT 2022