Setting up a Spring, Hibernate and MySQL project

Library Versions

This tutorial will be using Spring 3, Hibernate 4 and MySQL 5.

Maven Dependencies

Add the following dependencies into your pom.xml

MySQL

This is the JDBC driver, which is needed to connect to the MySQL database.

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.24</version>
</dependency>

commons-dbcp

This is the connection pool library.

<dependency>
  <groupId>commons-dbcp</groupId>
  <artifactId>commons-dbcp</artifactId>
  <version>1.4</version>
</dependency>

hibernate

Hibernate is the ORM library. We are using version 4.

<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-core</artifactId>
  <version>4.2.0.Final</version>
</dependency>

Spring

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-beans</artifactId>
  <version>3.2.2.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>3.2.2.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-orm</artifactId>
  <version>3.2.2.RELEASE</version>
</dependency>

Domain class and mapping

Create a domain class to be persisted. In this example I have a class named Person, which will be mapped into the Person table.

Person.java

public class Person {
  private Long id;
  private String firstName;
  private String lastName;
}

I’ve omitted the package name and getters and setters in this example.

Person.hbm.xml

Add a corresponding hibernate mapping. An alternative would be to annotate the Java class with mapping information.

<!DOCTYPE hibernate-mapping PUBLIC
          "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
          "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping auto-import="true">
  <class name="Person" table="Person">
    <id name="id">
        <generator class="native" />
    </id>
    <property name="firstName"/>
    <property name="lastName"/>
  </class>
</hibernate-mapping>

There is a new 4.0 xsd schema that comes with hibernate, but I wasn’t able to figure out how to use it.

Create a DAO

The @Transactional annotation is used when you need a connection to the database.

import org.hibernate.SessionFactory;

public class Dao {
    private SessionFactory sessionFactory;

    @Transactional(readOnly = false)
    public void savePerson(Person p) {
        sessionFactory.getCurrentSession().save(p);
    }

    public void setSessionFactory(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }
}

Spring context

Create your application context spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">
  <!-- connection pool -->
  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost/example"/>
    <property name="username" value="example"/>
    <property name="password" value="example"/>
    <property name="testOnBorrow" value="true"/>
    <property name="maxActive" value="10"/>
    <property name="minIdle" value="0"/>
    <property name="minEvictableIdleTimeMillis" value="60000"/>
    <property name="validationQuery" value="select 1 from dual"/>
  </bean>

  <!-- hibernate config -->
  <bean id="hibernateSessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="mappingResources">
      <list>
        <value>Person.hbm.xml</value>
      </list>
    </property>
    <property name="hibernateProperties">
      <props>
        <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
        <prop key="hibernate.show_sql">true</prop>
      </props>
    </property>
  </bean>

  <!-- our dao -->
  <bean id="dao" class="Dao">
    <property name="sessionFactory" ref="hibernateSessionFactory"/>
  </bean>

  <!-- @Transactional support -->
  <tx:annotation-driven/>
  <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="hibernateSessionFactory"/>
  </bean>

</beans>

Run it

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring.xml");
Dao dao = (Dao) ctx.getBean("dao");
Person p = new Person();
p.setFirstName("Joe");
p.setLastName("Bloggs");
dao.savePerson(p);

The above will:

1. Tell Spring to instantiate the beans
2. Get a reference to the Dao
3. Save a new Person into the database.