Lean example of Tomcat 8 + Guice 4 + Jersey 2.19

Posted on Wednesday Aug 05, 2015 at 02:36PM in Technology

Jersey is the RI of JAX-RS. in this entry, I introduce you how to use Jersey 2.19 with Guice 4 on Tomcat 8. it looks like there are some issues exist as follows but thanks to https://github.com/Squarespace/jersey2-guice , I’ve succeeded to use them anyway.

The entire project which based on Maven can be obtained from My GitHub repository.

Dependencies

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey</groupId>
            <artifactId>jersey-bom</artifactId>
            <version>2.19</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.containers</groupId>
        <artifactId>jersey-container-servlet</artifactId>
    </dependency>
    <dependency>
        <groupId>com.google.inject</groupId>
        <artifactId>guice</artifactId>
        <version>4.0</version>
    </dependency>
    <dependency>
        <groupId>com.google.inject.extensions</groupId>
        <artifactId>guice-servlet</artifactId>
        <version>4.0</version>
    </dependency>
    <dependency>
        <groupId>com.squarespace.jersey2-guice</groupId>
        <artifactId>jersey2-guice</artifactId>
        <version>0.10</version>
    </dependency>
</dependencies>

web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <servlet>
        <servlet-name>Jersey Web Application</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>guice.tomcat.jersey</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>Jersey Web Application</servlet-name>
        <url-pattern>/webapi/*</url-pattern>
    </servlet-mapping>

    <listener>
        <listener-class>guice.tomcat.MyJerseyGuiceServletContextListener</listener-class>
    </listener>

    <filter>
        <filter-name>guiceFilter</filter-name>
        <filter-class>com.google.inject.servlet.GuiceFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>guiceFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

MyJerseyGuiceServletContextListener.java

In this example, we use the servlet context listener named JerseyGuiceServletContextListener which comes from jersey2-guice artifact as parent class.

public class MyJerseyGuiceServletContextListener extends JerseyGuiceServletContextListener {
    @Override
    protected List<? extends Module> modules() {
        return Collections.singletonList(new ServletModule() {
            @Override
            protected void configureServlets() {
                bind(MyService.class).to(MyServiceImpl.class);
            }
        });
    }
}

Service class

We use very simple pair of an interface and implementation that creates a simple greeting message, which used in a past entry so omitted for simplicity.

MyResource.java

This is an simple implementation of JAX-RS resource class. placed under guice.tomcat.jersey package. the preceding service class named MyService will be injected by @javax.inject.Inject annotation.

@Path("myresource")
public class MyResource {

    @Inject
    private MyService myService;

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getIt() {
        return myService.hello("Jersey");
    }
}

Test run

$ curl http://localhost:8080/webapi/myresource
Hello, Jersey

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