JEE: GET and POST with JAX-RS

Environment

Apache Tomcat 7 (dockerized version)
MongoDB 2.6.7 (dockerized version)
JDK 7
Jersey Server 1.9
Spring 4.1.6
Clients: Java, Bash, Python, Javascript

Introduction and Project Description

A JAX-RS web application implemented in Jersey
Build Automation is handled using Maven
Deployment Environment is Apache Tomcat 7 (dockerized version)
Consumer can POST or GET a book entity.

Data is persisted in MongoDB (dockerized version)
The Spring Data Framework (1.7.0) is used to wrap the MongoDB Java Driver (2.11.0)

The Spring Framework (4.1.6 BOM) is used for component management
Consumers are provided in Java, Python and Javascript (jQuery 2.x)

What's new and different? Perhaps not much, depending on your background. I spent most of my early years coding JEE systems using Servlets and Web Services and relational databases with ORM providers to handle the mapping. Moving to JAX-RS seems cleaner, and MongoDB (in spite of the cumbersome syntax in Java) is far easier for simple persistence. No ORM mechanism required.

The application component model:

Fig 1: Component Model

The consumer can POST or GET a book entity to the application.

A JSON representation of the book entity looks like this: {"author":"Patrick OBrian","id":123,"title":"The Wine Dark Sea"}

The project source code is available at Github (reference below).

GET

The JAX-RS compliant-interface looks like:

@Path("/endpoint")
public class RestEndpoint {

 public static LogManager logger = new LogManager(RestEndpoint.class);

 @GET
 @Path("/get")
 @Produces(MediaType.APPLICATION_JSON)
 public Object get1(@QueryParam("id") Long id) {
   return getController().get(id);
 }

 @GET
 @Path("{id}")
 @Produces(MediaType.APPLICATION_JSON)
 public Object get2(@PathParam("id") Long id) {
  return get1(id);
 }

 // define POST methods ...
}

Using the first GET method, a consumer can query the system like this:

$ curl http://host:8080/blogger/demo/endpoint/123
{"author":"Patrick OBrian","id":123,"title":"The Wine Dark Sea"}

and use the second method like this:

$ curl http://host:8080/blogger/demo/endpoint/get?id=123
{"author":"Patrick OBrian","id":123,"title":"The Wine Dark Sea"}

Using the requests module in Python, the GET methods look like this:

import requests 

def g1():
 r = requests.get('http://host:8080/blogger/demo/endpoint/123')
 test(r.status_code)

def g2():
 payload = { 'id': '123' }
 headers = {'content-type': 'application/json'}
 r = requests.get('http://host:8080/blogger/demo/endpoint/get', params=payload)
 test(r.status_code)

def test(status_code):
 print 'status_code:', status_code
 assert (200 == status_code or 201 == status_code)

g1()
g2()

Using jQuery, the GET looks like this:

<html>
<head>
<script src="js/jquery-2.1.3.js"></script>
<script>

 var BASE = "http://host:8080/blogger/demo/endpoint/";

 $(document).ready(function() {
  $("#btnSubmitGET").click(function() {
   get($("#txtGET").val());
  });
 });

 /* get data by id */
 function get(id) {
  var url = BASE + id;
  $.getJSON(url, function(data) {
   /* create a list from the results */
   var items = [];
   $.each(data, function(key, val) {
    items.push("<li id='" + key + "'>" + val + "</li>");
   });

   $("<ul/>", {
    "class" : "my-new-list",
    html : items.join("")
   }).appendTo("body");
  });
 }

</script>
</head>

<body>
 <input type="text" name="id" value="9956" id="txtGET" class="id" />
 <input id="btnSubmitGET" type="submit" value="GET" />
</body>
</html>

and the result like this:

Fig 2: Results

Note: The example above is only testing the first GET method, but extending this into the second method (get?id=123) would be trivial.

POST

I've defined three POST methods that look like this:

@POST
@Path("/post")
@Consumes(MediaType.APPLICATION_JSON)
public Response post1(Book book) {
 logger.info("Invoked Post Method 1:\n\t%s", BookAdapter.toString(book));
 return getController().post(book);
}

@POST
@Path("/form")
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response post2(@FormParam("id") long id, @FormParam("author") String author, @FormParam("title") String title) {
 logger.info("Invoked Post Method 2:\n\tid = %s, author = %s, title = %s", id, author, title);
 return post1(BookAdapter.transform(id, title, author));
}

@POST
@Path("/{param}")
public Response post3(@PathParam("param") String msg) {
 logger.info("Invoked Post Method 3:\n\t%s", msg);
 try {

  Book book = GsonUtils.toObject(msg, Book.class);
  if (null != book) return post1(book);

 } catch (JsonSyntaxException e) {
  logger.error(e, "Invalid JSON (%s)", msg);
 }

 return ResponseAdapter.postFail("book", msg);
}

In the first case, I can GET and POST a Book entity from a Java consumer, like this:

package com.trimc.blogger.jaxrs;

import static org.junit.Assert.assertEquals;

import javax.ws.rs.core.MediaType;

import org.swtk.common.framework.LogManager;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.trimc.blogger.jaxrs.dto.Book;
import com.trimc.blogger.jaxrs.dto.BookAdapter;

public class WebResourceTester {

 public static LogManager logger = new LogManager(WebResourceTester.class);

 public static void main(String... args) throws Throwable {

  Client client = Client.create();
  Book book = BookAdapter.transform(12345l, "Nutmeg of Consolation", "Patrick O'Brian");

  WebResource webResourcePost = client.resource("http://host:8080/blogger/demo/endpoint/post");
  ClientResponse responsePost = webResourcePost.type(MediaType.APPLICATION_JSON).post(ClientResponse.class, book);

  logger.info("%s", responsePost.getEntity(String.class));

  WebResource webResourceGet = client.resource("http://host:8080/blogger/demo/endpoint/" + book.getId());
  ClientResponse responseGet = webResourceGet.type(MediaType.APPLICATION_JSON).get(ClientResponse.class);

  Book _book = responseGet.getEntity(Book.class);
  assertEquals(book.hashCode(), _book.hashCode());
 }
}

In the form POST method, I can use standard HTML:

<html>
<head>
<body>
 <h3>Demonstrate HTML Form POST</h3>
 <form action="http://192.168.1.7:8080/blogger/demo/endpoint/form"
  method="post">
  <p>
   ID : <input type="text" name="id" value="123" />
  </p>
  <p>
   Author : <input type="text" name="author" value="Patrick OBrian" />
  </p>
  <p>
   Title : <input type="text" name="title" value="The Wine Dark Sea" />
  </p>
  <input type="submit" value="POST" />
 </form>
</body>
</html>

Fig 3: Form POST

and the result demonstrated via RoboMongo:

Fig 4: JSON Results

The third method in jQuery looks like this:

<html>
<head>
<script src="js/jquery-2.1.3.js"></script>
<script>
 var BASE = "http://host:8080/blogger/demo/endpoint/";

 $(document).ready(function() {
  initTextarea();
  $("#btnSubmitPOST").click(function() {
   post($("#txtPOST").val());
  });
 });

 /* initialize the textarea with a payload */
 function initTextarea() {
  var payload = {
   "author" : "Patrick O'Brian",
   "id" : 1234,
   "title" : "The Wine Dark Sea"
  };

  $("#txtPOST").val(JSON.stringify(payload));
 }

 /* post json data */
 function post(id) {
  try {

   var url = BASE + id;
   $.post(url, function(data, status) {
    alert("Data: " + data + "\nStatus: " + status);
   });

  } catch (e) {
   alert(e);
  }
 }
</script>
</head>

<body>
 <h3>Demonstrate JSON POST</h3>
 <textarea name="id" id="txtPOST" class="id" rows="4" cols="50"></textarea>
 <input id="btnSubmitPOST" type="submit" value="POST" />
</body>
</html>

The submission is just JSON in a textarea sent directly to the client:

Fig 5: JSON Post Form

and a demonstration via Robomongo that the data was indeed persisted:

Fig 6: JSON Results

The last two approaches are also shown below in Python:

import requests 

# STATUS CODES:
#  <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>
#  200 = OK
#  201 = Created

def post2():
 payload = { 'author' : 'p5-author', 'id' : '9995', 'title' : 'p5-title' }
 headers = {u'content-type': u'application/x-www-form-urlencoded'} 
 r = requests.post("http://host:8080/blogger/demo/endpoint/form", params=payload, headers=headers) 
 test(r.status_code)
 return r.text

def post3():
 r = requests.post( 'http://host:8080/blogger/demo/endpoint/{"author":"this is my content","title":"my title","id":9956}' )
 test(r.status_code)
 return r.text

def test(status_code):
 print 'status_code:', status_code
 assert (200 == status_code or 201 == status_code)

p5();
p6()

References

[GitHub] Source Code for this article [or, Google Drive for a zip file]
Resources:

GitHub] Apache Tomcat 7 (configured for this blog post)
[Docker Register] MongoDB Dockerfile

HOWTO Articles:

[Blog] Setting up Apache Tomcat and Docker
[Blog] Working with MongoDB (Installation and Usage)
[Blog] Using Maven for Build Automation

JEE

Thursday, April 9, 2015

GET and POST with JAX-RS

Environment

Introduction and Project Description

GET

POST

References

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