JAX-RS Get HTTP Headers using @Context

October 12, 2019 howtojava Jersey 0

In this tutorial we are going to see how to get HTTP request header using JAX-RS @Context annotation (Jersey RESTful web service)

Create maven web application project and add Jersey dependency in pom.xml. Find Jersey 2.x maven dependency configuration below. If you are new to maven refer our maven tutorials.

Jersey 2.x dependency in pom.xml

<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.ehowtonow</groupId>
  <artifactId>RestTutorials</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>RestTutorials Maven Webapp</name>
  <url>http://maven.apache.org</url>
   <properties>
        <jersey2.version>2.19</jersey2.version>
        <jaxrs.version>2.0.1</jaxrs.version>
    </properties>
  <dependencies>
      <!-- JAX-RS -->
        <dependency>
            <groupId>javax.ws.rs</groupId>
            <artifactId>javax.ws.rs-api</artifactId>
            <version>${jaxrs.version}</version>
        </dependency>
        <!-- Jersey 2.19 -->
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-server</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-client</artifactId>
            <version>${jersey2.version}</version>
        </dependency>
  </dependencies>
  <build>
    <finalName>RestTutorials</finalName>
  </build>
</project>

HTTPHeaderService.java

package com.ehowtonow.webservice;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.Response;

@Path("/tutorial")
public class HTTPHeaderService {

	@GET
	@Path("/java-tutorial")
	public Response getTutorial(@Context HttpHeaders httpHeaders) {
		String userAgent = httpHeaders.getRequestHeader("user-agent").get(0);
		return Response.status(200).entity("User Agent Details : " + userAgent).build();
	}
}

In this tutorials I used user-agent alone. You can access all http headers using @Context

Configure Jersey 2.x Servlet dispatcher

<!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>
	<display-name>Restful Webservice Example</display-name>
	<servlet>
		<servlet-name>jersey-serlvet</servlet-name>
		<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
             <param-name>jersey.config.server.provider.packages</param-name>
			<param-value>com.ehowtonow.webservice</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>jersey-serlvet</servlet-name>
		<url-pattern>/rest/*</url-pattern>
	</servlet-mapping>
</web-app>

Now you can run the service and access the service by calling the following URL

http://localhost:8080/RestTutorials/rest/tutorials/java-tutorial

Output :

User Agent Details : Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36

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