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183 lines
6.7 KiB
Markdown
183 lines
6.7 KiB
Markdown
# Spring Bootstrap
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Spring Bootstrap is "Spring for Snowboarders". If you are kewl, or
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just impatient, and you want to use Spring, then this is the place to
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be. Spring Bootstrap is a toolkit and runtime platform that will get
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you up and running with Spring-powered, production-grade applications
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and services with absolute minimum fuss. It takes an opinionated view
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of the Spring family so that new and existing users can quickly get to
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the bits they need. Assumes no knowledge of the Java development
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ecosystem. Absolutely no code generation and no XML (unless you really
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want it).
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The goals are:
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* Radically faster and widely accessible getting started experience
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for Spring development
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* Be opinionated out of the box, but get out of the way quickly as
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requirements start to diverge from the defaults
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* Provide a range of non-functional features that are common to large
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classes of projects (e.g. embedded servers, security, metrics,
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health checks, externalized configuration)
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* First class support for REST-ful services, modern web applications,
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batch jobs, and enterprise integration
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* Applications that adapt their behaviour or configuration to their
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environment
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* Optionally use Groovy features like DSLs and AST transformations to
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accelerate the implementation of basic business requirements
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## Installing
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You need to build from source for now, but when it's done instructions will look like this:
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1) Get Java. Download and install the Java SDK from www.java.com
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2) Get Spring
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$ curl -s try.spring.io | bash
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or use the Windows installer
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3) Get to Work!
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$ cat > app.groovy
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@Controller
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class ThisWillActuallyRun {
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@RequestMapping("/")
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@ResponseBody
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String home() {
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return "Hello World!"
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}
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}
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$ spring run app.groovy
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$ curl localhost:8080
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Hello World!
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## What? It's Groovy then? or like Grails? or Roo?
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There is a command line tool that uses Groovy underneath so that we
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can present simple snippets that can just run just like the slimline
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`app.groovy` example above. Groovy makes this really easy.
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If you don't want to use the command line tool, or you would rather
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work using Java and an IDE you can. Just add a `main()` method that
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calls `SpringApplication` and add `@EnableAutoConfiguration`:
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import org.springframework.stereotype.*;
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import org.springframework.web.bind.annotation.*;
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import org.springframework.bootstrap.context.annotation.*;
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@Controller
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@EnableAutoConfiguration
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public class SampleController {
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@RequestMapping("/")
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@ResponseBody
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String home() {
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return "Hello World!"
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}
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public static void main(String[] args) throws Exception {
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SpringApplication.run(SampleController.class, args);
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}
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}
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## Spring Bootstrap Themes
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There are a number of themes in Bootstrap. Here are the important
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ones:
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### The Spring CLI
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The 'spring' command line application compiles and runs Groovy source,
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making it super easy to write the absolute minimum of code to get an
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application running. Spring CLI can also watch files, automatically
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recompiling and restarting when they change.
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### Bootstrap Core
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The main library providing features that support the other parts of
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Spring Bootstrap. Features include:
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* `SpringApplication` - a class with static convenience methods that
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make it really easy to write a standalone Spring Application. Its
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sole job is to create and refresh an appropriate Spring
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`ApplicationContext`.
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* Embedded web applications with a choice of container (Tomcat or
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Jetty for now)
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* `@EnableAutoConfigure` is an annotation that triggers
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auto-configuration of the Spring context. Auto-configuration
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attempts to guess what beans a user might want based on their
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classpath. For example, If a 'HSQLDB' is on the classpath the user
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probably wants an in-memory database to be
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defined. Auto-configuration will back away as the user starts to
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define their own beans.
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* `@Conditional` is an annotation in Spring 4.0 that allows you to
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control which parts of an application are used at runtime. Spring
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Bootstrap provides some concrete implementations of conditional
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configuration, e.g. `@ConditionalOnBean`,
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`@ConditionalOnMissingBean` and `@ConditionalOnClass`.
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### Spring Bootstrap Actuator
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Spring Bootstrap Actuator uses auto-configuration features to decorate
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your application with features that make it instantly deployable and
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supportable in production. For instance if you are writing a JSON web
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service then it will provide a server, security, logging, externalized
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configuration, management endpoints, an audit abstraction, and more.
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If you want to switch off the built in features, or extend or replace
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them, it makes that really easy as well.
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### Service Wrappers and Deployability
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Spring Bootstrap helps you to take that last step from finishing a
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development iteration to getting the code running in production.
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Without having to think too much about it, other than choosing your
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deployment environment (CentOS, Ubuntu, Windows etc) you should be
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able to stand up an instance, or multiple instances, of your component
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and have them fit seamlessly into the operating system environment.
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### Spring Bootstrap Starters
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Spring Bootstrap Starters are a set of convenient dependency
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descriptors that you can include in your application. You get a
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one-stop-shop for all the Spring and related technology that you need
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without having to hunt through sample code and copy paste loads of
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dependency descriptors. For example, if you want to get started using
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Spring and JPA for database access just include one dependency in your
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project, and you are good to go.
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## Building the code
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Use maven to build the source code.
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$ mvn clean install
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## Importing into eclipse
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You can use m2e or `maven eclipse:eclipse`.
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Project specific settings are configured for source formatting. If you
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are using m2e you can follow these steps to install eclipse support
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for formatting:
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* Select `Install new software` from the `help` menu
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* Click `Add...` to add a new repository
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* Click the `Archive...` button
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* Select `org.eclipse.m2e.maveneclipse.site-0.0.1-SNAPSHOT-site.zip`
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from the `eclipse` folder in this checkout
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* Install "Maven Integration for the maven-eclipse-plugin"
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Or if you prefer you can import settings manually from the `/eclipse` folder.
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## Samples
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The following samples are included. To run use `java -jar target/<archive>.jar`
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* spring-bootstrap-simple-sample - A simple command line application
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* spring-bootstrap-jetty-sample - Embedded Jetty
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* spring-bootstrap-tomcat-sample - Embedded Tomcat
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* spring-bootstrap-service-sample - Simple REST service with production features
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* spring-batch-sample - Define and run a Batch job in a few lines of code
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* spring-bootstrap-data-sample - Spring Data JPA + Hibernate + HSQLDB
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