tasks-rs: JAX-RS, JPA quickstart

Author: Mike Musgrove
Level: Intermediate
Technologies: JPA, JAX-RS
Summary: Demonstrates how to use JAX-RS and JPA together
Prerequisites: tasks
Target Product: EAP
Product Versions: EAP 6.1, EAP 6.2
Source: https://github.com/jboss-developer/jboss-eap-quickstarts/

What is it?

This project demonstrates how to implement a JAX-RS service that uses JPA 2.0 persistence.

• The client uses HTTP to interact with the service. It builds on the tasks quickstarts which provide simple Task management with secure login.

• The service interface is implemented using JAX-RS. The SecurityContext JAX-RS annotation is used to inject the security details into each REST method.

The application manages User and Task JPA entities. A user represents an authenticated principal and is associated with zero or more Tasks. Service methods validate that there is an authenticated principal and the first time a principal is seen, a JPA User entity is created to correspond to the principal. JAX-RS annotated methods are provided for associating Tasks with this User and for listing and removing Tasks.

Note: This quickstart uses the H2 database included with JBoss EAP 6. It is a lightweight, relational example datasource that is used for examples only. It is not robust or scalable and should NOT be used in a production environment!

System requirements

The application this project produces is designed to be run on Red Hat JBoss Enterprise Application Platform 6.1 or later.

All you need to build this project is Java 6.0 (Java SDK 1.6) or later, Maven 3.0 or later.

Configure Maven

If you have not yet done so, you must Configure Maven before testing the quickstarts.

Add an Application User

This quickstart uses secured management interfaces and requires that you create the following application user to access the running application.

UserName	Realm	Password	Roles
quickstartUser	ApplicationRealm	quickstartPwd!!	guest

To add the application user, open a command prompt and type the following command:

    For Linux:   EAP_HOME/bin/add-user.sh -a -u 'quickstartUser' -p 'quickstartPwd1!' -g 'guest'
    For Windows: EAP_HOME\bin\add-user.bat  -a -u 'quickstartUser' -p 'quickstartPwd1!' -g 'guest'

If you prefer, you can use the add-user utility interactively. For an example of how to use the add-user utility, see instructions in the root README file located here: Add an Application User.

Start the JBoss EAP Server

1. Open a command prompt and navigate to the root of the JBoss EAP directory.

2. The following shows the command line to start the server:

    For Linux:   EAP_HOME/bin/standalone.sh
    For Windows: EAP_HOME\bin\standalone.bat
   

Build and Deploy the Quickstart

NOTE: The following build command assumes you have configured your Maven user settings. If you have not, you must include Maven setting arguments on the command line. See Build and Deploy the Quickstarts for complete instructions and additional options.

1. Make sure you have started the JBoss EAP server as described above.

2. Open a command prompt and navigate to the root directory of this quickstart.

3. Type this command to build and deploy the archive:

    mvn clean install jboss-as:deploy
   

4. This will deploy target/jboss-tasks-rs.war to the running instance of the server.

Access the Application Resources

Application resources for this quickstart are prefixed with the URL http://localhost:8080/jboss-tasks-rs/ and can be accessed by an HTTP client.

• For methods that accept GET, a web browser can be used.
• Otherwise, you must use cURL or some other command line tool that supports HTTP POST and DELETE methods.

Below you will find instructions to create, display, and delete tasks.

Create a Task

To associate a task called task1 with the user quickstartUser, you must authenticate as user quickstartUser and send an HTTP POST request to the url 'http://localhost:8080/jboss-tasks-rs/tasks/task1'.

To issue the POST command using cURL, type the following command:

curl -i -u 'quickstartUser:quickstartPwd1!' -H "Content-Length: 0" -X POST http://localhost:8080/jboss-tasks-rs/tasks/task1

You will see the following response:

HTTP/1.1 201 Created
Server: Apache-Coyote/1.1
Location: http://localhost:8080/jboss-tasks-rs/tasks/1
Content-Length: 0
Date: Sun, 15 Apr 2012 22:46:26 GMT

This is what happens when the command is issued:

• The -i flag tells cURL to print the returned headers. Notice that the Location header contains the URI of the resource corresponding to the new task you have just created.
• The -u flag provides the authentication information for the request.
• The -H flag adds a header to the outgoing request.
• The -X flag tells cURL which HTTP method to use. The HTTP POST is used to create resources.
• The Location header of the response contains the URI of the resource representing the newly created task.

The final argument to cURL determines the title of the task. Note that this approach is perhaps not very restful but it simplifies this quickstart. A better approach would be to POST to "http://localhost:8080/jboss-tasks-rs/tasks" passing the task title in the body of the request.

Display the XML Representation of a Task

To display the XML representation of the newly created resource, issue a GET request on the task URI returned in the Location header during the create.

1. To issue a GET using a browser, open a browser and access the URI. You will be challenged to enter valid authentication credentials.

   http://localhost:8080/jboss-tasks-rs/tasks/1

2. To issue a GET using cURL, type the following command:

    curl -H "Accept: application/xml" -u 'quickstartUser:quickstartPwd1!' -X GET http://localhost:8080/jboss-tasks-rs/tasks/1
   

   The `-H flag tells the server that the client wishes to accept XML content.

Using either of the above GET methods, you should see the following XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <task id="1" ownerName="quickstartUser">
      <title>task1</title>
  </task>

Display the XML Representation of all Tasks for a User

To obtain a list of all tasks for user quickstartUser in XML format, authenticate as user quickstartUser and send an HTTP GET request to the resource tasks URL.

1. To issue a GET using a browser, open a browser and access the following URL. You will be challenged to enter valid authentication credentials.

   http://localhost:8080/jboss-tasks-rs/tasks

2. To list all tasks associated with the user quickstartUser using cURL, type:

    curl -H "Accept: application/xml" -u 'quickstartUser:quickstartPwd1!' -X GET http://localhost:8080/jboss-tasks-rs/tasks
   

Using either of the above GET methods, you should see the following XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<collection>
    <task id="1" ownerName="quickstartUser">
    <title>task1</title>
    </task>
</collection>

Delete a Task

To delete a task, again authenticate as principal quickstartUser and send an HTTP DELETE request to the URI that represents the task.

To delete the task with id 1:

curl -i -u 'quickstartUser:quickstartPwd1!' -X DELETE http://localhost:8080/jboss-tasks-rs/tasks/1

You will see this response:

HTTP/1.1 204 No Content
Server: Apache-Coyote/1.1
Pragma: No-cache
Cache-Control: no-cache
Expires: Thu, 01 Jan 1970 01:00:00 GMT
Date: Sun, 15 Apr 2012 22:51:56 GMT

Now list all tasks associated with user quickstartUser:

curl -u 'quickstartUser:quickstartPwd1!' -X GET http://localhost:8080/jboss-tasks-rs/tasks

You will see a response with an empty collection:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<collection/>

Modify this Quickstart to Support JSON Representations of Tasks

JSON is not part of the JAX-RS standard but most JAX-RS implementations do support it. This quickstart can be modified to support JSON by uncommenting a few lines. Look for lines beginning with "// JSON:":

1. Open the file src/org/jboss/as/quickstarts/tasksrs/model/Task.java and remove the comments from the following two lines.

    // import org.codehaus.jackson.annotate.JsonIgnore;
   
    // @JsonIgnore
   

2. Open the file src/org/jboss/as/quickstarts/tasksrs/service/TaskResource.java and make sure the GET methods produce "application/json" as well as "application/xml". Again, look for lines beginning with "// JSON:".

   • Remove comments from these lines:

     //@Produces({ "application/xml", "application/json" })

   • Add comments to these lines:

     @Produces({ "application/xml" })

3. Open pom.xml and remove the comments from the dependency with artifactId resteasy-jackson-provider

    <!--
    <dependency>
        <groupId>org.jboss.resteasy</groupId>
        <artifactId>resteasy-jackson-provider</artifactId>
        <version>2.3.1.GA</version>
        <scope>provided</scope>
    </dependency>
    -->
   

4. Create a Task as you did in the for the XML version of this quickstart.

5. Rebuild and redeploy the quickstart.

Now you can view task resources in JSON media type by specifying the correct Accept header. For example, using the cURL tool, type the following command:

curl -H "Accept: application/json" -u 'quickstartUser:quickstartPwd1!' -X GET http://localhost:8080/jboss-tasks-rs/tasks/1

You will see the following response:

{"id":1,"title":"task1","ownerName":"quickstartUser"}

Server Log: Expected warnings and errors

Note: You will see the following warnings and errors in the server log. Hibernate attempts to drop the table and constraints before they are created because the hibernate.hbm2ddl.auto value is set to create-drop. You can ignore these warnings and errors.

    HHH000431: Unable to determine H2 database version, certain features may not work

    HHH000389: Unsuccessful: alter table Task drop constraint FK_kxfu633bvt1sptgbnkxkrr3qf
    Table "TASK" not found; SQL statement: alter table Task drop constraint FK_kxfu633bvt1sptgbnkxkrr3qf [42102-168]

Undeploy the Archive

1. Make sure you have started the JBoss EAP server as described above.

2. Open a command prompt and navigate to the root directory of this quickstart.

3. When you are finished testing, type this command to undeploy the archive:

    mvn jboss-as:undeploy
   

Run the Quickstart in JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts from Eclipse using JBoss tools. For more information, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts

Debug the Application

If you want to debug the source code or look at the Javadocs of any library in the project, run either of the following commands to pull them into your local repository. The IDE should then detect them.

    mvn dependency:sources
    mvn dependency:resolve -Dclassifier=javadoc