Java ORM example application
The following tutorial implements a REST API server using the Hibernate ORM. The scenario is that of an e-commerce application. Database access in this application is managed through Hibernate ORM.
The source for this application can be found in the Using ORMs with YugabyteDB repository.
Prerequisites
This tutorial assumes that you have:
- YugabyteDB up and running. Download and install YugabyteDB by following the steps in Quick start.
- Java Development Kit (JDK) 1.8, or later, is installed. JDK installers for Linux and macOS can be downloaded from OpenJDK, AdoptOpenJDK, or Azul Systems.
- Apache Maven 3.3, or later, is installed.
Clone the "orm-examples" repository
$ git clone https://github.com/YugabyteDB-Samples/orm-examples.git
There are a number of options that can be customized in the properties file located at src/main/resources/hibernate.cfg.xml
. Given YSQL's compatibility with the PostgreSQL language, the hibernate.dialect
property is set to org.hibernate.dialect.PostgreSQLDialect
and the hibernate.connection.url
is set to the YSQL JDBC URL: jdbc:postgresql://localhost:5433/yugabyte
.
Build the application
$ cd orm-examples/java/hibernate
$ mvn -DskipTests package
Run the application
Start the Hibernate application's REST API server at http://localhost:8080
.
$ mvn exec:java -Dexec.mainClass=com.yugabyte.hibernatedemo.server.BasicHttpServer
Send requests to the application
Create 2 users.
$ curl --data '{ "firstName" : "John", "lastName" : "Smith", "email" : "jsmith@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
$ curl --data '{ "firstName" : "Tom", "lastName" : "Stewart", "email" : "tstewart@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
Create 2 products.
$ curl \
--data '{ "productName": "Notebook", "description": "200 page notebook", "price": 7.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
$ curl \
--data '{ "productName": "Pencil", "description": "Mechanical pencil", "price": 2.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
Create 2 orders.
$ curl \
--data '{ "userId": "2", "products": [ { "productId": 1, "units": 2 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
$ curl \
--data '{ "userId": "2", "products": [ { "productId": 1, "units": 2 }, { "productId": 2, "units": 4 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
Query results
Using the YSQL shell
$ ./bin/ysqlsh
ysqlsh (11.2)
Type "help" for help.
yugabyte=#
List the tables created by the app.
yugabyte=# \d
List of relations
Schema | Name | Type | Owner
--------+-------------------------+----------+----------
public | orderline | table | yugabyte
public | orders | table | yugabyte
public | orders_user_id_seq | sequence | yugabyte
public | products | table | yugabyte
public | products_product_id_seq | sequence | yugabyte
public | users | table | yugabyte
public | users_user_id_seq | sequence | yugabyte
(7 rows)
Note the 4 tables and 3 sequences in the list above.
yugabyte=# SELECT count(*) FROM users;
count
-------
2
(1 row)
yugabyte=# SELECT count(*) FROM products;
count
-------
2
(1 row)
yugabyte=# SELECT count(*) FROM orders;
count
-------
2
(1 row)
yugabyte=# SELECT * FROM orderline;
order_id | product_id | units
--------------------------------------+------------+-------
45659918-bbfd-4a75-a202-6feff13e186b | 1 | 2
f19b64ec-359a-47c2-9014-3c324510c52c | 1 | 2
f19b64ec-359a-47c2-9014-3c324510c52c | 2 | 4
(3 rows)
Note that orderline
is a child table of the parent orders
table connected using a foreign key constraint.
Using the REST API
$ curl http://localhost:8080/users
{
"content": [
{
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
{
"userId": 1,
"firstName": "John",
"lastName": "Smith",
"email": "jsmith@example.com"
}
],
...
}
$ curl http://localhost:8080/products
{
"content": [
{
"productId": 2,
"productName": "Pencil",
"description": "Mechanical pencil",
"price": 2.5
},
{
"productId": 1,
"productName": "Notebook",
"description": "200 page notebook",
"price": 7.5
}
],
...
}
$ curl http://localhost:8080/orders
{
"content": [
{
"orderTime": "2019-05-10T04:26:54.590+0000",
"orderId": "999ae272-f2f4-46a1-bede-5ab765bb27fe",
"user": {
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
"userId": null,
"orderTotal": 25,
"products": []
},
{
"orderTime": "2019-05-10T04:26:48.074+0000",
"orderId": "1598c8d4-1857-4725-a9ab-14deb089ab4e",
"user": {
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
"userId": null,
"orderTotal": 15,
"products": []
}
],
...
}