Develop Reference

Add a Controller class to a Servlet using Jersey Annotation getting 404

In the web.xml is defined this servlet mapping:
<servlet>
<servlet-name>JAX-RS External REST Servlet</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>xxx.rest.external.XxxExternalRestApplication</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.config.feature.DisableWADL</param-name>
<param-value>true</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>JAX-RS External REST Servlet</servlet-name>
<url-pattern>/external/rest/*</url-pattern>
</servlet-mapping>
I cannot modify the web.xml.
I have created a WebAppplicationInitializer in order to get the registered Servlet on the path /external/rest
Here is the code:
package com.xxx.extended.base.config.sailpoint;
import com.xxx.extended.controllers.IRestControllerMarker;
import com.xxx.extended.controllers.LocalManagedEntitlementsRestController;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.glassfish.jersey.server.ServerProperties;
import org.glassfish.jersey.servlet.ServletProperties;
import org.springframework.web.WebApplicationInitializer;
import javax.servlet.ServletContext;
/**
* Uses to extend parameter of external rest api to include custom controllers
*/
public class XxxExternalRestWebApplicationInitializer implements WebApplicationInitializer
{
private static final Logger log = LogManager.getLogger(XxxExternalRestWebApplicationInitializer.class);
/**
* Rest api servlet name
*/
private static final String REST_SERVLET_NAME = "JAX-RS External REST Servlet";
#Override
public void onStartup(ServletContext servletContext) {
log.debug("Try to get external servlet by name:[{}]", REST_SERVLET_NAME);
var registration = servletContext.getServletRegistration(REST_SERVLET_NAME);
if (registration == null) {
log.error("Could not find external servlet registration. External api will not work!!!!");
return;
}
registration.setInitParameter(ServerProperties.PROVIDER_PACKAGES, LocalManagedEntitlementsRestController.class.getPackageName());
log.debug("Registered the controllers from this package: [{}]",IRestControllerMarker.class.getPackage().getName());
}
}
After the startup of the application the WebApplicationInitializer is actually recognized, but when I am sending a GET request to the controller I get a 404 Not Found, I pretty sure the URL is fine.
Actually it seems not scanning the package to fetch the controllers to show.
My feeling is that because in the Application defined:
xxx.rest.external.XxxExternalRestApplication
the controllers class are registed sigularly, it is not going scan packages.
Here the simplified code of the controller I'm trying to use:
#Path("custom")
public class LocalManagedEntitlementsRestController extends BaseResource
{
private static final Logger log = LogManager.getLogger(LocalManagedEntitlementsRestController.class);
#GET
#Path("/")
public String sayHello()
{
return "Welcome to the world of REST";
}
}

json conversion using jersey

I am using jar files instead of maven because i dont have internet.
problem: i am using jersey implemenation of jax-rs. i need to convert the java to json but it is giving the following error
java.lang.NoSuchMethodError: org.glassfish.jersey.internal.util.PropertiesHelper.getValue(Ljava/util/Map;Ljavax/ws/rs/RuntimeType;Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Class;)Ljava/lang/Object;
at org.glassfish.jersey.moxy.json.MoxyJsonFeature.configure(MoxyJsonFeature.java:67)
at org.glassfish.jersey.model.internal.CommonConfig.configureFeatures(CommonConfig.java:730)
at org.glassfish.jersey.model.internal.CommonConfig.configureMetaProviders(CommonConfig.java:648)
at org.glassfish.jersey.server.ResourceConfig.configureMetaProviders(ResourceConfig.java:829)
at org.glassfish.jersey.server.ApplicationHandler.initialize(ApplicationHandler.java:453)
at org.glassfish.jersey.server.ApplicationHandler.access$500(ApplicationHandler.java:184)
at org.glassfish.jersey.server.ApplicationHandler$3.call(ApplicationHandler.java:350)
at org.glassfish.jersey.server.ApplicationHandler$3.call(ApplicationHandler.java:347)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.processWithException(Errors.java:255)
at org.glassfish.jersey.server.ApplicationHandler.<init>(ApplicationHandler.java:347)
at org.glassfish.jersey.servlet.WebComponent.<init>(WebComponent.java:392)
at org.glassfish.jersey.servlet.ServletContainer.init(ServletContainer.java:177)
at org.glassfish.jersey.servlet.ServletContainer.init(ServletContainer.java:369)
at javax.servlet.GenericServlet.init(GenericServlet.java:158)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1236)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1149)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1041)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4910)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5192)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1387)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
the code i am using is:
package mypack;
import javax.websocket.server.PathParam;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import org.glassfish.jersey.server.BackgroundScheduler;
import entity.Res;
#Path("/s")
public class webapi {
#GET
#Path("q/{name}")
#Produces(MediaType.APPLICATION_JSON)
public Res method(#PathParam("name") String name){
try{
Res r = new Res();
r.setId(5);
r.setName(name);
return r;
}catch(Exception e){
System.out.println(e.getMessage());
return null;
}
}
}
the res class is as follow:
package entity;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
#XmlRootElement
public class Res {
#XmlElement int id;
#XmlElement String name;
public Res() {
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
the jar files that i am using are:
web.xml file is :
<?xml version="1.0" encoding="UTF-8"?>
<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_3_0.xsd" id="WebApp_ID" version="3.0">
<servlet>
<servlet-name>Jersey REST Service</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>mypack</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Jersey REST Service</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
</web-app>
what is the reason for the error?

I Think there may be a problem with the jar Versioning . Because the jar that you used for your Project is Older Version. Please update your lib to update the jersey dependency as i see and predict the error.
I would suggest you to add jars atleast of Version 2.7 instead of 2.2 or 2.3 as your dependency Says.
Please Update your lib Folder then Clean your Project .
Build Your Project again. After Updating your lib with New jar Files .
Thank You

The requested URL /REST/WebService/MyMethod was not found on this server

i'm new to REST Service. i've done a small REST Webservice application and deployed in my online tomcat webserver,
My link -->
http://sample.com.au/REST/WebService/MyMethod?name=sss
but i'm getting the following message
The requested URL /REST/WebService/MyMethod was not found on this server.
when i run the similar in eclipse locally its working....
can anyone please tell me some solution for this...
my web.xml
<?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>
:
:
<servlet>
<servlet-name>ServletAdaptor</servlet-name>
<servlet-class>com.sun.jersey.server.impl.container.servlet.ServletAdaptor</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>ServletAdaptor</servlet-name>
<url-pattern>/REST/*</url-pattern>
</servlet-mapping>
</web-app>
My FeedService.java
package webService;
import java.util.ArrayList;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import model.ProjectManager;
import com.google.gson.Gson;
import dto.FeedObjects;
#Path("/WebService")
public class FeedService {
#GET
#Path("/MyMethod")
#Produces("application/json")
public String names(#QueryParam("name") String name)
{
System.out.println("name----------->"+name);
String feeds = null;
try
{
ArrayList<FeedObjects> feedData = null;
ProjectManager projectManager= new ProjectManager();
feedData = projectManager.GetFeeds(name);
Gson gson = new Gson();
System.out.println(gson.toJson(feedData));
feeds = gson.toJson(feedData);
}
catch (Exception e)
{
System.out.println("Exception Error"); //Console
}
return feeds;
}
}
context.xml
<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" path="/iloadlogistics.com.au"/>

Refer here. Specifically check Example 4.1 and Example 4.5. Should you not deploy that way?

Counting the number of users in web App in servlet

I have modified my application to find out the number of users logged in a web application below is my piece of code..
the listener class
import javax.servlet.ServletContext;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class SessionCounter implements HttpSessionListener
{
private static int count;
public static int getActiveSessions() {
return count;
}
public SessionCounter()
{
}
//The "sessionCount" attribute which has been set in the servletContext should not be modified in any other part of the application.
//Since we are using serveltContext in both the methods to modify the same variable, we have synchronized it for consistency.
public void sessionCreated(HttpSessionEvent e)
{
count++;
ServletContext sContext = e.getSession().getServletContext();
synchronized (sContext)
{
sContext.setAttribute("sessionCount", new Integer(count));
}
}
public void sessionDestroyed(HttpSessionEvent e)
{
count--;
ServletContext sContext = e.getSession().getServletContext();
synchronized (sContext)
{
sContext.setAttribute("sessionCount", new Integer(count));
}
}
}
and the main servlet is ..
package com.saral;
import java.io.IOException;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class First
*/
//#WebServlet("/First")
public class MyServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
static final Logger logger = Logger.getLogger(MyServlet.class);
/**
* #see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PropertyConfigurator.configure("log4j.properties");
logger.info("before---->");
// TODO Auto-generated method stub
String name=request.getParameter("txtName");
response.setContentType("text/html");
PrintWriter out=response.getWriter();
out.println("Hello,"+name);
out.println("<br> this output is generated by a simple servlet.");
out.println("Total Number of users logged in--->"+SessionCounter.getActiveSessions());
out.close();
}
}
and the web.xml is ...
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>FirstDemo</display-name>
<context-param>
<param-name>log4jConfigLocation</param-name>
<param-value>/WEB-INF/log4j.properties</param-value>
</context-param>
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>com.saral.MyServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/helloServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>home.html</welcome-file>
</welcome-file-list>
<listener>
<listener-class>com.saral.SessionCounter</listener-class>
</listener>
</web-app>
but I am getting the total number of users logged in as 0 , which is not perfect, please advise where I am wrong and how can I overcome from this.

When a client request come to the Tomcat server and you don't call request.getSession(), then the Tomcat server stil creates a session automatically. After that, the method sessionCreated(...) in your SessionCounter class is called.
The method sessionDestroyed(...) will be called when a session is destroyed. That occurs when you call session.invalidate(). If you close a tab on browser or close a browser, the session is still alive on your tomcat server.
I think so. You can use some diffrent listeners to archive your goal: HttpSessionAttributeListener, HttpSessionBindingListener,...

Integrating Jetty with RESTEasy

Any links on how to integrate Jetty and RESTEasy? I am kinda stuck trying to configure RESTEasy with Jetty together....and there seems to be no credible help on the web.
public static void main(String[] args) throws Exception
{
Server server = new Server(8080);
WebAppContext context = new WebAppContext();
context.setDescriptor("../WEB-INF/web.xml");
context.setResourceBase("../src/webapp");
context.setContextPath("/");
context.setParentLoaderPriority(true);
server.setHandler(context);
server.start();
server.join();
}
My Web.xml is copied directly from:
http://docs.jboss.org/resteasy/docs/1.0.0.GA/userguide/html/Installation_Configuration.html
The error I get back is a HTTP 404 when I try to open up a link in my resource file. Everything looks reasonable on the surface, any suggestions?
My resource file looks like:
package webapp;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
#Path("/*")
public class Resource {
#GET
public String hello() {
return "hello";
}
#GET
#Path("/books")
public String getBooks() {
return "books";
}
#GET
#Path("/book/{isbn}")
public String getBook(#PathParam("isbn") String id) {
return "11123";
}
}
This is the prints that I see when Jetty starts up:
2012-04-10 09:54:27.163:INFO:oejs.Server:jetty-8.1.1.v20120215 2012-04-10 09:54:27.288:INFO:oejw.StandardDescriptorProcessor:NO JSP Support for /, did not find org.apache.jasper.servlet.JspServlet 2012-04-10 09:54:27.319:INFO:oejsh.ContextHandler:started o.e.j.w.WebAppContext{/,file:/C:/Users/xyz/Anotherproj1/src/webapp} 2012-04-10 09:54:27.319:INFO:oejsh.ContextHandler:started o.e.j.w.WebAppContext{/,file:/C:/Users/xyz/Anotherproj1/src/webapp} 2012-04-10 09:54:27.381:INFO:oejs.AbstractConnector:Started SelectChannelConnector#0.0.0.0:8080

The follwing works for me:
web.xml:
<web-app xmlns:javaee="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<context-param>
<param-name>resteasy.scan</param-name>
<param-value>true</param-value>
</context-param>
<context-param>
<param-name>resteasy.resources</param-name>
<param-value>webapp.Resource</param-value>
</context-param>
<context-param>
<param-name>javax.ws.rs.core.Application</param-name>
<param-value>webapp.MyApplicationConfig</param-value>
</context-param>
<!-- set this if you map the Resteasy servlet to something other than /*
<context-param>
<param-name>resteasy.servlet.mapping.prefix</param-name>
<param-value>/resteasy</param-value>
</context-param>
-->
<!-- if you are using Spring, Seam or EJB as your component model, remove the ResourceMethodSecurityInterceptor -->
<context-param>
<param-name>resteasy.resource.method-interceptors</param-name>
<param-value>
org.jboss.resteasy.core.ResourceMethodSecurityInterceptor
</param-value>
</context-param>
<listener>
<listener-class>org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener-class>
</listener>
<servlet>
<servlet-name>Resteasy</servlet-name>
<servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Resteasy</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>
With
public class MyApplicationConfig extends Application {
private static final Set<Class<?>> CLASSES;
static {
HashSet<Class<?>> tmp = new HashSet<Class<?>>();
tmp.add(Resource.class);
CLASSES = Collections.unmodifiableSet(tmp);
}
#Override
public Set<Class<?>> getClasses(){
return CLASSES;
}
}
Resource
package webapp;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
#Path("/")
#Produces("text/plain")
public class Resource {
#GET
public String hello() {
return "hello";
}
#GET
#Path("/books")
public String getBooks() {
return "books";
}
#GET
#Path("/book/{isbn}")
public String getBook(#PathParam("isbn") String id) {
return "11123";
}
}
and Main Class
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.webapp.WebAppContext;
import org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap;
public class Main {
public static void main(String[] args) throws Exception
{
Server server = new Server(8080);
WebAppContext context = new WebAppContext();
context.setDescriptor("./src/main/webapp/WEB-INF/web.xml");
context.setResourceBase("./src/main/webapp");
context.setContextPath("/");
context.setParentLoaderPriority(true);
server.setHandler(context);
server.start();
server.join();
}
}

Are you sure that #Path("/*") is correct path. Try #Path("/") maybe this * is a problem. As far as I know path expressions does not accept regexps.
EDIT
I was wrong, you can use regexps in #Path, at least RESTEasy supports that.

To get RESTEasy and Jetty to work together without a web.xml ensure you have a dependency on resteasy-servlet-initializer in your pom.xml.
This may help (JBoss RESTEasy documentation): https://docs.jboss.org/resteasy/docs/3.0.4.Final/userguide/html/Installation_Configuration.html#d4e111