Spring Hibernate Using Annotations

Overview

Prerequisites
Create a new Java project in Maven
Java project skeleton structure
Data Entities
Code

This tutorial will show you how to use annotation with Spring Hibernate

Prerequisites

You will need to install the following technical components:

Java 1.7.x
Maven 3.0.5
Spring Framework 3.0.6
Hibernate 3.6.3

Create a new Java project in Maven

The simplest way to quickly create a new Java project in Maven is to utilise Maven Archetype (Quickstart)

$ mvn archetype:generate -DgroupId=com.addison.database -DartifactId=SpringHibernateUsingAnnotations -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

Java project skeleton structure

SpringHibernateUsingAnnotations
│   pom.xml
│
└───src
    ├───main
    │   └───java
    │       └───com
    │           └───addison
    │               └───database
    │                       App.java
    │
    └───test
        └───java
            └───com
                └───addison
                    └───database
                            AppTest.java

This essentailly creates a Hello world application! Since we do not need App or AppTest classes, these should just be deleted.

Data Entities

For this example let us consider persisting a Trade entity, with attributes product name, product code, bur or sell, quantity, price, trade date; and an Account, which is modelled as another first class entity.

Annotated Trade Entity & Columns

import javax.persistence.*;

@Entity
public class Trade {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "trade_id", nullable = false, insertable = false, updatable = false)
    private Long tradeId;

    @Column(name = "buySell", nullable = false, length = 4)
    private String buySell;

    @Column(name = "quantity", nullable = false)
    private Double quantity;

    @Column(name = "symbol", nullable = true, length = 20)
    private String symbol;

    @Column(name = "price", nullable = false)
    private Double price;

    @ManyToOne(cascade = CascadeType.ALL)
    private Account account;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "trade_date", nullable = false)
    public java.util.Date tradeDate = new java.util.Date();
}

Annotated Account Entity & Columns

import javax.persistence.*;

@Entity
public class Account {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "account_id", nullable = false, insertable = false, updatable = false)
    private Long accountId;

    @Column(name = "name", nullable = false, length = 40)
    private String name;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "creation_date", nullable = false)
    private java.util.Date creationDate = new Date();

    @OneToMany(mappedBy = "account", cascade = CascadeType.ALL)
    private Set<Trade> trades = new HashSet<Trade>();
}

This is my hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <!-- Database connection settings, Connect to HSQL -->
    <property name="dialect">org.hibernate.dialect.HSQLDialect</property>
    <property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
    <property name="connection.url">jdbc:hsqldb:mem:testdb</property>
    <property name="connection.username">SA</property>
    <property name="connection.password"></property>
    <!-- property name="show_sql">true</property>
    <property name="format_sql">true</property -->
    <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
    <!--create the database schema on startup if required -->
    <property name="hbm2ddl.auto">create</property>
    <mapping class="com.addison.database.entity.Account"></mapping>
    <mapping class="com.addison.database.entity.Trade"></mapping>
  </session-factory>
</hibernate-configuration>

Code

The source code is available from my public Github repository SpringHibernateUsingAnnotations

Mark Addison