Posts Tagged JPA
Connecting Java EE RESTful web services, hosted on GlassFish, to Microsoft SQL Server – a high level overview. Demonstrate the creation of a Web Application project in NetBeans, including a SQL Server data source, entity classes from a SQL database, and RESTful web services. Show how to test and deploy the project to GlassFish.
In a previous post, Connecting Java EE to SQL Server with Microsoft’s JDBC Driver 4.0, I demonstrated how Microsoft’s JDBC Driver 4.0 can connect Java-based RESTful web services to Microsoft SQL Server. In a more recent post, Calling Microsoft SQL Server Stored Procedures from a Java Application Using JDBC, I demonstrated the use of JDBC to call stored procedures from a Java application. In this post, I am going to offer a high-level, end-to-end overview on how to create and connect Java EE RESTful web services, hosted on GlassFish, to SQL Server. The goals of post are:
- Demonstrate the use of Microsoft’s JDBC Driver 4.0 to connect a Java-based application to SQL Server 2008 R2;
- Demonstrate the use of NetBeans to:
- Create a SQL Server Data Source;
- Create entity classes from the SQL Server database using the SQL Server Data Source;
- Create RESTful web services using JAX-RS, which communicate with database, through the entity classes;
- Compile and deploy the data source, entities, and services to GlassFish;
- Test the RESTful Web Services locally in NetBeans, and once deployed, in GlassFish.
Setting up the Post’s Example
To demonstrate the example in this post, I have the follow applications installed, configured, and running in my development environment:
- Microsoft SQL Server 2008 R2 (www.microsoft.com/sqlserver)
- Microsoft’s Adventure Works 2008 R2 Sample Database (msftdbprodsamples.codeplex.com)
- Microsoft JDBC Driver 4.0 for SQL Server (msdn.microsoft.com/en-us/sqlserver/aa937724.aspx)
- NetBeans 7.2 Open Source IDE (netbeans.org)
- Apache Any 1.82 (installed with NetBeans or downloaded separately from ant.apache.org)
- GlassFish 220.127.116.11 Open Source Edition Application Server (installed with NetBeans or downloaded separately from glassfish.java.net)
If you have any questions about installing and configuring the Adventure Works database, please refer to my post, Convert VS 2010 Database Project to SSDT and Automate Publishing with Jenkins – Part 1/3. The post takes you through creating a SQL Server 2008 R2 instance (entitled ‘Development’), installing the Adventure Works database, and creating a database user (‘aw-dev’). Also, refer to my earlier post, Connecting Java EE to SQL Server with Microsoft’s JDBC Driver 4.0, for directions on installing the Microsoft JDBC driver in the lib directory of GlassFish. This is necessary before following along with this demonstration.
Note, since I have NetBeans, SQL Server, and GlassFish all installed on a single computer, the URLs in several of the screen-grabs switch between ‘localhost’ and my computer’s actual name. Both references are interchangeable.
Here are the high-level steps I will walk-through in this post:
- Confirm the SQL Server instance, database, and user are functioning properly;
- Create a new Web Application project in NetBeans;
- Create the SQL Server data source in the project;
- Create entity classes from the SQL Server database;
- Create RESTful web services using the entity classes;
- Test the web services locally in NetBeans;
- Build and deploy the project to GlassFish;
- Test the web services on GlassFish.
Using Microsoft’s SQL Server Management Studio, Quest’s Toad for SQL, or similar IDE, confirm the ‘Development’ instance (or whatever you have named your instance) of SQL Server 2008 R2 is running. Confirm the Adventure Works database is installed in that instance. Lastly, confirm the ‘aw_dev’ user can connect to the Adventure Works database and view and interact with all the database objects. Confirming these items will elevate many problems you might otherwise encounter when creating the data source, next.
Create New Web Application Project
Create a new Java Web Application project in NetBeans. Name the project whatever you would like; I named mine ‘JdbcSqlWebSrvTest’. Select the correct GlassFish server instance and GlassFish domain where the project will be deployed. I am deploying my project to the default ‘domain1’ domain.
Create SQL Server Data Source and Entity Classes from the Database
Right-click on the project again and select ‘New’ -> ‘Other…’. From the list of Categories, select ‘Persistence’. From the list of Persistence choices, choose ‘Entity Classes from Database’. Click Next.
Before we can choose which database tables we want from the Adventure Works database to create entity classes, we must create a connection to the database – a SQL Server Data Source. Click on the Data Source drop down and select ‘New Data Source…’. Give a Java Naming and Directory Interface (JNDI) name for the data source. I called mine ‘AdventureWorks’. Click on the ‘Database Connection’ dropdown, select ‘New Database Connection…’.
This starts the ‘New Connection Wizard’. The first screen, ‘Locate Driver’, is where we point the will instruct NetBeans to use the Microsoft JDBC Driver 4.0 for SQL Server Driver. Locate the sqljdbc4.jar file.
On the next screen, ‘Customize the Connection’, input the required SQL Server information. The host is the machine your instance of SQL Server is installed on, such as ‘localhost’. The instance is the name of the SQL Server instance in which the Adventure Works database is installed, such as ‘Development’. Once you complete the form, click ‘Test Connection’. If it doesn’t succeed, check your settings, again.
As I mentioned in an earlier post, the SQL Server Data Source forces you to select a single database schema. On the ‘Choose Database Schema’ screen, select the ‘HumanResources’ schema. The database tables you will be able to reference from you entity classes are limited to just this schema, when using this data source. To reference other schemas, you will need to create more data sources.
Back in the ‘New Entity Classes from Database’ window, you will now have the ‘AdventureWorks’ data source selected as the Data Source. After a few seconds of processing, all ‘Available Tables’ within the ‘HumanResources’ schema are displayed. Choose the four tables shown in the screen-grab, below. Actually, two are database tables and two are virtual tables, called database ‘views’. We will need to do an extra step later on, to use the two entity classes built from the database views.
On the next screen, ‘Entity Classes’, in the ‘New Entity Classes from Database’ window, give a package name to place the individual entity classes into. I chose to call mine ‘entityclasses’.
On the next screen, ‘Mapping Options’, choose ‘Fully Qualified Database Table Names’. Without this option selected, I have had problems trying to make the RESTful web services function properly. This is also the reason I chose to create the entity classes first, and then create the RESTful web services, separately. NetBeans has an option that combines these two tasks into a single step, by choosing ‘RESTful Web Services from Database’. However, the ‘Fully Qualified Database Table Names’ option is not available on the equivalent screen, using that process (at least in my version of NetBeans 7.2). I prefer the two-step approach.
Click finished. You have successfully created the SQL Server data source and entity classes.
The data source we created, which will be deployed to GlassFish, is referred to as a JDBC Resource and a JDBC Connection Pool. This JDBC information is stored in the ‘glassfish-resources.xml’ file by NetBeans.
The JPA Persistence Unit is found in the ‘persistence.xml’ file in the ‘Configuration Files’ folder. This file describes the Persistence Unit (PU). The PU serves to register the project’s four persistable entity classes, which are referred to by JPA as managed classes.
RESTful Web Services from Entity Classes
Now that have a SQL Server Data Source and our entity classes, we will create the RESTful web services. Right-click on the project and select ‘New’ -> ‘Other…’ -> ‘Persistence’ -> ‘RESTful Web Services from ‘Entity Classes’. You will see a list of four entity classes we just created, from which to choose. Add all four entity classes.
On the next screen, give a name for Resource Package to store the service classes in; I called mine ‘service’. That’s it; you now have four RESTful web services and the corresponding Enterprise Beans and Façade service classes. The service class sits between the RESTful web service and the entity class.
Click finished. You have successfully created the RESTful web services.
Adding a Primary Key to Entity Classes
If you recall, I mentioned a problem with the two entity classes we created from the database views. To avoid an error when you build and deploy your project to GlassFish, we need to make a small change to the VEmployee.java and VEmployeeDepartment.java entity classes. Entity classes need a unique identifier, a primary key (or, Entity ID) identified. Since these two entity classes are built from database views, as opposed to database tables, they lack a primary key. To fix this, annotate the ‘businessEntityID’ field with ‘@Id’ in each class. This indicates that ‘businessEntityID’ is the primary key (Entity ID) for this class. The field, ‘businessEntityID’, must contain unique values, for this to work properly. NetBeans will make the suggested correction for you, if you allow it.
Test RESTful Web Services Locally in NetBeans
NetBeans provides an easy way to test the RESTful web services, locally. Right-click on the ‘RESTful Web Services’ project folder within the main project, and select ‘Test RESTful Web Services’. Select the first option, ‘Locally Generated Test Client’, in the ‘Configure REST Test Client’ pop-up window.
NetBeans will open a web browser window and displays the RESTful URI (Universal Resource Identifier) for the services in a tree structure. There are four primary URIs, corresponding to the four services. Each primary URI has additional child URIs grouped under them. Are they URIs or URLs? I found this excellent post that does a very good job explaining the difference between the URL (how to get there) and the URI (the resource), which is part of the URL.
Click on the ‘entityclasses.employee’ URI. Choose the HTTP ‘GET()’ request method from the drop-down and click the ‘Test’ button. The service should return a status of ‘200 (OK)’, along with xml output containing information on all the Adventure Works employees. Congratulation, the RESTful web services have just returned data to your browser from the SQL Server Adventure Works database, using the entity classes and data source you created.
Click on the other URIs to familiarize yourself with the various default resources. Test the employee ‘from/to’ URI by inputting two parameters, test the ‘count’ URI, and try changing the MIME type where applicable from XML to JSON and observe the results.
Note the link in the upper right corner of the above screens, labeled WADL: ‘http://[your_server_path]/JdbcSqlWebSrvTest/webresources/application.wadl’
The WADL (Web Application Description Language) file is the machine-readable XML description of the RESTful web service(s). The WADL file is to RESTful web services, as the WSDL (Web Service Definition Language) file is to non-RESTful, SOA-/SOAP-oriented web services. The WADL provides all the information you need to understand to the various RESTful web service’s resources, and how to call them using their URIs. According to Wikipedia, in the WADL file, ‘the service is described using a set of resource elements. Each resource has param elements to describe the inputs, and method elements which describe the request and response of a resource. The request element specifies how to represent the input, what types are required and any specific HTTP headers that are required. The response describes the representation of the service’s response, as well as any fault information, to deal with errors.’ You can download the WADL file (application.wadl), and review it in an XML-friendly viewer such as Notepad++.
Deploy Project to GlassFish
Now that the RESTful web services are working properly from within NetBeans, we can deploy them to GlassFish. To deploy the project to GlassFish, right-click on the main project icon in the Projects tab and select ‘Clean and Build’. Once the project builds successfully, right-click again and select ‘Deploy’. This will instruct Apache Ant to deploy the project as a .war file to GlassFish, using the project’s default Ant deploy task. The SQL Server data source will also be installed into GlassFish.
Once the deployment is complete, switch to GlassFish and refresh the home page if necessary. Under the ‘Applications’ item on the left-hand navigation menu, you should see a new application with the same name as your project, ‘JdbcSqlWebSrvTest’.
Also, under the ‘JDBC’ -> ‘JDBC Resources’ item, you should see a resource with the same name as the data source you created in NetBeans, ‘AdventureWorks’. Under the ‘JDBC’ -> ‘JDBC Connection Pools’, you should see a pool entitled ‘microsoft_sql_AdventureWorks_aw_devPool’. The JDBC Resource, ‘AdventureWorks’, is linked to this pool. The pool is a ‘javax.sql.DataSource’ resource type, which references the ‘com.microsoft.sqlserver.jdbc.SQLServerDataSource’. This data source is identical to the data source you built in NetBeans.
Test Web Services on GlassFish
To test the RESTful web services from GlassFish, begin by clicking on the ‘JdbcSqlWebSrvTest’ application, under ‘Applications’ menu item. On the Applications page, click on the ‘Launch’ action link. GlassFish open a new web browser window, and presents you with two ‘Web Application Links’, one link is HTTP and the other, HTTPS. Click on the HTTP link. This should display the default index.jsp page’s ‘Hello World!’ message.
To call the service, append the current URL to match the resource URIs you used when testing the services in NetBeans. For example, to display all the employees again like you did in NetBeans, append the current URL, http://%5Byour_server_name%5D:%5Bport%5D/JdbcSqlWebSrvTest/, to include the following:
This URI should return the same xml content you observed when testing this same URI locally in NetBeans.
As another test, append the URI to also include the Id of a single employee, as follows:
This should cut the amount of data returned from the Adventure Works database to a single employee record.
One last test, remove the number two from the URI and add the word ‘count’, as follows:
This time, you should see a single integer returned to the browser, representing the count of all employees in the database’s employee table.
Congratulations, the Java EE RESTful web services have been successfully deployed to GlassFish. The services are connecting to Adventure Works SQL Server database, through the entity classes and data source, and returning data to your web browser! Next step is to create a RESTful web services client application, to display the data returned by the services and/or to perform CRUD operations on the database.
Connect Microsoft SQL Server to Java EE JPA and JAXB with MOXy technologies using Microsoft’s JDBC Driver 4.0.
A t-sql script to create the three database tables used in this post is available on DropBox. If you like DropBox, please use this link to sign up for a free 2 GB account. It will help me post more files to DropBox for future posts.
Recently, I read a very good five-part blog series, Creating a RESTful Web Service, by Blaise Doughan. The series of posts demonstrate the effective use of JPA, JAXB with MOXy (JPA Entities to XML), EJB, and JAX-RS. Although Blaise’s series was written in 2010, the information it has is still quite relevant and insightful. I was interested in working through the sample project the series is based on. However, I wanted to use Microsoft’s SQL Server instead of Oracle as the data source. In this post, I detail changes I made to the series’ example project to work with SQL Server, using Microsoft’s JDBC Driver SQL Server.
Blaise’s blog, Java XML & JSON Binding (Object-to-XML and object-to-JSON mapping using JAXB and EclipseLink MOXy), is located at blog.bdoughan.com. According to his blog, Blaise is the Team lead for the TopLink / EclipseLink JAXB & SDO implementations, and the Oracle representative on those specifications. His blog is overflowing with a wealth of information on a number of Java EE technologies, including Java Persistence Architecture (JPA), Java Architecture for XML Binding (JAXB), Enterprise JavaBeans (EJB), Java API for RESTful Web Services (JAX-RS), and Oracle’s GlassFish application server.
Microsoft SQL Server as Data Source
In my current position, I work regularly with Microsoft’s relational database, SQL Server 2008 R2. However, Blaise’s blog series example uses Oracle Database XE. Using the Java EE technology stack, but switching the data source to SQL Server was relatively easy using Microsoft JDBC Driver 4.0 for SQL Server. The 4.0 version of the driver was just released in March of 2012. It includes the ability to interface with Microsoft’s new SQL Server 2012, and is also backwards compatible to SQL Server 2005. Of course there are alternative third-party SQL Server drivers, including those from DataDirect, i-net software, and so forth. I chose to use Microsoft’s own JDBC driver.
Before connecting to SQL Server using Microsoft’s JDBC driver, you need to create a SQL Server database, mirroring the database schema in Blaise’s blog post. You can easily translate the Oracle, native PL/SQL TABLE CREATE scripts into T-SQL. Once you’ve set up the three database tables and related relationships, your database schema should resemble the database diagram displayed below.
The only change I made was to designate the
ID primary key column in the
CUSTOMER table as an auto-incrementing
IDENTITY column. This allows inserting of new customers in the
CUSTOMER table without having to manually manage unique IDs. You will note some extra annotations in the Customer entity class if you make the identity column change.
Configuring Microsoft’s JDBC Driver with NetBeans
Microsoft’s JDBC driver downloadable install package has two JAR class libraries, one supports JDBC 3.0 for use with JRE version 5, and another supports JDBC 4.0 for JRE 6. I used the later JAR file, sqljdbc4.jar, to build database connections based on my project’s designated JRE.
I’m currently using NetBeans IDE 7.1.1. To create a database connection in NetBeans, on the Services tab, right-click on Databases, and select New Connection… If this is your first time using the Microsoft driver, under Locate Driver, Driver drop down list, select New Driver… In the New JDBC Driver window, select one of the driver’s two JAR files (see explanation above). There is only one Driver Class, chosen by default. You can change the name of the driver as it appears in driver list, or leave NetBeans’ default descriptive connection naming convention format:
jdbc:sqlserver://[SERVER_NAME]\[INSTANCE_NAME];databaseName=CustomerService [[USER_NAME] on [SCHEMA_NAME]]
After setting up the new JDBC driver, select Next to set up the details of the specific database instance and database you wish to connect to for your project. Following Blaise’s blog, connect to the Customer Service database created earlier. I chose to connect to the database by inputting my database server, instance, and database names. Alternately, you could connect using TCP/IP (assuming it’s enabled), by inputting your SQL Server’s network name or IP address, and the port you have configured for SQL Server connections. Your setup will be specific to your environment, but should look like the below.
One limitation of Microsoft’s JDBC driver is that it requires you to select a specific database schema, as part of the last step in the connection creation process. Each specific database connection will only display database objects from the selected schema. In a production environment, where you may have multiple schemas, this can add complexity to managing connections.
When finished, you will see your newly created Microsoft SQL Server driver listed under Drivers. You will also see your newly created database connection, using the Microsoft JDBC driver, listed under Databases. From this point on, you can follow Blaise’s series, substituting the Oracle database connection with the new SQL Server database connection in the Persistence Unit’s JDBC Connection drop down menu.
If you decide to move beyond the scope of Blaise’s series’ example project, you may want the ability to call the methods and properties of the SQL Server driver, directly in your code. To do so, add the driver’s JAR file to your project by right-clicking on the Libraries folder of your project on the Projects tab, and select Add JAR/Folder… Again, I added the same JAR file, sqljdbc4.jar, for use with JRE 6. Then, import the driver’s class library packages as necessary, such as
com.microsoft.sqlserver.jdbc.SQLServerDataSource, used to build a SQL Server data source.
Configuring Microsoft’s JDBC Driver with GlassFish
To host the example web service in the blog series, you also need to install Microsoft’s JDBC driver on your application server; in the case of Blaise’s series, Oracle’s GlassFish Server. To install the driver on GlassFish 3.1.2, right-click on the GlassFish server instance in the Servers tab in NetBeans and select View Domain Admin Console. GlassFish’s administration console should appear in your web browser, assuming GlassFish is installed and running. You can follow the blog’s instructions to set up the JDBC Connection Pool and JDBC Resource, selecting MicrosoftSqlServer from the Database Driver Vendor drop down menu. If this option is not available, make sure you installed the driver’s JAR file in GlassFish’s lib folder, as explained in the first blog of Blaise’s series, and try restarting GlassFish in NetBeans. Be sure to close the Admin Console in the web browser first.