Over a million developers have joined DZone.

Easy Tricks for JPA, Spring and Hibernate

· Java Zone

Discover how AppDynamics steps in to upgrade your performance game and prevent your enterprise from these top 10 Java performance problems, brought to you in partnership with AppDynamics.

Java frameworks have evolved, making us write less code and ship faster! Here, I will discuss some neat tricks to address common concerns in Hibernate and Spring.

1. Auto Scan JPA entities. This is an old trick!

Listing entities (via <class> element)  in persistence.xml isn't needed any more. You may drop it all together and use Spring's packagesToScan feature. Sample spring configuration below.

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
 <property name="persistenceUnitName" value="HelloService" />
 <property name="packagesToScan" value="com.x.y.z" />
 <property name="dataSource" ref="dataSource" />
 <property name="jpaVendorAdapter">
  <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
   <property name="showSql" value="true" />
   <property name="databasePlatform" value="org.hibernate.dialect.MySQL5Dialect" />

2.Entities often have audit columns like the following: 

@Column(name = "created_by", updatable = false)
protected String createdBy;

@Column(name = "creation_date", updatable = false)
protected Date createdOn;

@Column(name = "last_updated_by")
protected String lastUpdatedBy;

@Column(name = "last_updated")
protected Date lastUpdatedOn;

And providing those values require either writing pre-insert/update Hibernate listeners or writing setters. How about sprinkling some annotations to get the job done? I mean ... 

@Column(name = "created_by", updatable = false)
protected String createdBy;

@Column(name = "creation_date", updatable = false)
protected Date createdOn;

@Column(name = "last_updated_by")
protected String lastUpdatedBy;

@Column(name = "last_updated")
protected Date lastUpdatedOn; 

It is quite simple. Read this:http://docs.jboss.org/hibernate/orm/4.3/topical/html/generated/GeneratedValues.html

3. Applications are deployed in different environments and configuring those are often messy and by messy I mean repetitive. Spring property place holder has a neat trick by using property of property to dynamically create the property key for each environment.

Sample common properties file for all environments. 

# ec2.properties is a properties for all environment.  

dev.awsAccountId = 11111111111
dev.availabilityZone = us-east-1a
dev.keyName = dev
dev.expiry = 360000
dev.instanceType = m1.small

beta.awsAccountId = 222222222222
beta.availabilityZone = us-east-1a
beta.keyName = beta
beta.expiry = 360000
beta.instanceType = m1.large

Here is how you will use this file in spring context configuration - 

<bean id="ec2Settings"  class="x.y.z.EC2Settings">  
 <property name="accountId" value="${awsAccountId}" />  
 <property name="zone" value="${availabilityZone}" />  
 <property name="key" value="${keyName}" />  
 <property name="expiry" value="${expiry}" />
 <property name="instanceType" value="${instanceType}" />  

The Java Zone is brought to you in partnership with AppDynamics. AppDynamics helps you gain the fundamentals behind application performance, and implement best practices so you can proactively analyze and act on performance problems as they arise, and more specifically with your Java applications. Start a Free Trial.


Published at DZone with permission of Nishant Chandra, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

The best of DZone straight to your inbox.

Please provide a valid email address.

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}