1© 2016 Pivotal

Spring Boot under the Hood

Nicolas Fränkel, Senior Consultant, SAP hybris

@nicolas_frankel

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Me, Myself and I

@nicolas_frankel #springboot

Developer/Software -/Solution Architect

• Java

• As consultant

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hybris, an SAP company

@nicolas_frankel #springboot

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Spring Boot actuator

@nicolas_frankel #springboot

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-actuator</artifactId>

</dependency>

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/health

@nicolas_frankel #springboot

{"status" : "UP","diskSpace" : {

"status" : "UP","total" : 499055067136,"free" : 254812135424,"threshold" : 10485760

},"db" : {

"status" : "UP","database" : "HSQL Database Engine","hello" : 1

} }

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Spring boot

Works well until:

• It doesn’t anymore

• Or you want to change the default behavior

@nicolas_frankel #springboot

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There’s no magic involved

@nicolas_frankel #springboot

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Configuration – pom.xml

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

<dependency>

<groupId>org.hsqldb</groupId>

<artifactId>hsqldb</artifactId>

<scope>runtime</scope>

</dependency>

@nicolas_frankel #springboot

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Starters dependencies

@nicolas_frankel #springboot

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spring-boot-autoconfigure.jar

@nicolas_frankel #springboot

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spring.factories

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@JPARepositoriesAutoConfiguration

@Configuration@ConditionalOnBean(DataSource.class)@ConditionalOnClass(JpaRepository.class)@ConditionalOnMissingBean({

JpaRepositoryFactoryBean.class,JpaRepositoryConfigExtension.class })

@ConditionalOnProperty(prefix = "spring.data.jpa.repositories",name = "enabled", havingValue = "true",matchIfMissing = true)

@Import(JpaRepositoriesAutoConfigureRegistrar.class)@AutoConfigureAfter(HibernateJpaAutoConfiguration.class)public class JpaRepositoriesAutoConfiguration {}

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@Conditional

@ConditionalOnBean

@ConditionalOnClass

@ConditionalOnMissingBean

@ConditionalOnProperty

etc.

@nicolas_frankel #springboot

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Remember @Profile?

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.TYPE)

public @interface Profile {

String[] value();

}

@nicolas_frankel #springboot

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This is the new @profile

@Retention(RetentionPolicy.RUNTIME)

@Target({ElementType.TYPE, ElementType.METHOD})

@Documented

@Conditional(ProfileCondition.class)

public @interface Profile {

String[] value();

}

@nicolas_frankel #springboot

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@conditional & condition

@nicolas_frankel #springboot

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@conditional & condition

Enables calling of a @Bean-annotated method

• In the context of a @Configuration class

@nicolas_frankel #springboot

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Demo

Let’s play with

conditionals

@nicolas_frankel #springboot

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Out-of-the-box conditions

@nicolas_frankel #springboot

Condition Description

OnBeanCondition Checks if a bean is in the Spring factory

OnClassCondition Checks if a class is on the classpath

OnExpressionCondition Evalutates a SPeL expression

OnJavaCondition Checks the version of Java

OnJndiCondition Checks if a JNDI branch exists

OnPropertyCondition Checks if a property exists

OnResourceCondition Checks if a resource exists

OnWebApplicationCondition Checks if a WebApplicationContext exists

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Out-of-the-box conditions

@nicolas_frankel #springboot

Condition Description

AllNestedConditions AND condition

AnyNestedConditions OR condition

NoneNestedCondition NOT condition

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Demo

Our own starter

@nicolas_frankel #springboot

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Q&A

@nicolas_frankel #springboot

http://blog.frankel.ch/

@nicolas_frankel

http://frankel.in/

https://git.io/v2f3O

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Chicago: May 30, 31

New York: June 20-21

Atlanta: July 18-19

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1. Core Spring

2. Spring Professional

Certification

3. Enterprise Spring

4. Enterprise Integration

Specialist Certification

Prerequisites

ILT | 2 days

Learn how to use Spring

Cloud Data Flow to manage

data processing use cases

Spring Cloud Data Flow

Developer

ILT & LOL | 2 days

Learn how to develop

Spring cloud native

applications using Spring

Cloud Services

Spring Cloud Services

Spring Training and Certification

1. Core Spring

2. Spring Professional

Certification

Prerequisites

ILT, LOL & ELT | 2 days

Learn how to create

applications using Spring

Boot

Spring Boot Developer

ILT, LOL & ELT | 2 days

Learn how to create

applications using Spring

Boot

Spring Boot Developer

Legend:ILT= Instructor Led Training

LOL= Live Online

ELT= eLearning

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