spring-boot-tutorial - "Bootiful" Applications with Spring Boot

Run

if you want ot run the server from command line, run maven package and run the jar

mvn package
java -jar spring-boot-tutorial-0.1.0.jar

step 1

basic app with rest

checkout step 1:

git checkout step1

In this step we have a basic web application with a rest resource run application.java and open your browser: http://localhost:8080/

note that the server runs automatically on port 8080 , and using embedded tomcat. to change the port - uncomment the server.port property in applicaion.properties restart the server. now we use port 8090: http://localhost:8090/

unit test: we have a unit test for this rest resource: HelloControllerTest MockMvc is used to test the rest resources without loading the whole server

Integration test: HelloControllerItTest in this test we start the server with a random port:

@IntegrationTest({"server.port=0"}) //generate a random port

and we can use the random port with this property:

@Value("${local.server.port}") //get the generated port
private int port;

now by using Spring's Http Client - RestTemplate we can send a request to our resuorce.

step 2

actuator

checkout step 2:

git checkout step2

we added this dependency in the pom:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

The actuator provides production ready features to help you monitor and manage your application for example, try running the following resources : http://localhost:8090/metrics http://localhost:8090/health http://localhost:8090/mappings http://localhost:8090/beans all this data is also available via JMX

step 3

websocket

checkout step 3:

git checkout step3

two classes added: WsHandler & WsConfig in WsConfig we define the handlers, and WsHandler is our handler.

use this page to test ws: http://www.websocket.org/echo.html

task: implement a welcome message when connecting.

• hint: implement method afterConnectionEstablished

Step 4

git checkout step4

websocket - welcome message & custom counter metrics are cool, by for websocket we don't have a built in metric for number of messages so lets add one:

lets just autowire the service to get it:

@Autowired
CounterService counterService;

and use it:

counterService.increment("ws.total.messages");

see the result in the metrics: http://localhost:8090/metrics

Step 5

change implementation to Jetty

git checkout step5

all we need to do to change to implementation is add the right dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jetty</artifactId>
</dependency>

Step 6

log configuration by default - spring boot has its own logback configuration

git checkout step6

added logback.xml but still using spring defaults - by including them

<include resource="org/springframework/boot/logging/logback/defaults.xml" />
<property name="LOG_FILE" value="${LOG_FILE:-${LOG_PATH:-${LOG_TEMP:-${java.io.tmpdir:-/tmp}}/}spring.log}"/>
<include resource="org/springframework/boot/logging/logback/console-appender.xml" />
<include resource="org/springframework/boot/logging/logback/file-appender.xml" />

Step 7

JDBC

git checkout step7

this will enable us to access a DB (fully preconfigured by spring boot) by creating a pojo as an Entity, and creating an interface of Repository (no implementation class needed!)

add dependency for the JPA starter:

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

and for H2 db:

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>

have a look at Person pojo & PersonRepository interace

custom health check: have a look at H2Health - it implements a HealthIndicator and can tell the service when this component is UP or DOWN http://localhost:8090/health

Task 1: implement GET by id as a rest operation in PersonController

Task 2: implement all CRUD operations, paging, page size , search by name ,add links - self , prev , next.

what??? how is anyone supposed to implement all that in 1 hour tutorial?? lets wait with this task for the next step...

Step 8

JPA REST Spring boot has built in support to "Restify" the repository

add this dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>

add @RepositoryRestResource to our PersonRepository and @Param("name") to the name parameter in method findPersonByName

have a look at all the available REST operations: http://localhost:8090/persons/

Step 9

using liveperson's parent pom

git checkout step9

since we want to use our own parent pom - we need to take all the dependncies by imporing spring boot pom instead of using it as parent. use the folloing:

<dependencyManagement>
        <dependencies>
            <dependency>
                <!-- Import dependency management from Spring Boot -->
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>1.3.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

#Step 10 deploying spring boot app spring boot has the capability to run the jar as a script - to be able to run as a service. you can pass arguments to it like JAVA_HOME, JAVA_OPTS and many more. more details here: http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/html/deployment-install.html#deployment-service

this is not part of the actual tutorial - just for general reference

add this snippet to your deployment app:

file {'/etc/rc.d/init.d/LPBootApp':
    ensure => 'link',
    target => "/liveperson/code/<myBootApp>/<myBootApp-1.0.0.0.jar>",
  }

this will create a service that can get commands like start stop status & restart