Case study: Java 8 + Spring boot

I've made an internal application using newest technologies and aproaches.

Here is case study of what I achived and what I found interesting about new technology stack.

Slides contains examples of:
- Java 8 feautures
- Spring boot
- Thymeleaf
- Gradle
- front-end builds

Transcript

1. Case study Classic MVC with separated front-end Piotr Lewandowski @piotlr
2. Back-end Java 8 Spring 4 + Spring boot Apache POI Thymeleaf Gradle Front-end bootstrap require.js npm bower gulp
3. Java 8
4. Java 7 way Java 8 way List<Human> humans = ... Collections.sort(humans, new Comparator<Human>() { @Override public int compare(Human h1, Human h2) return h1.getName().compareTo(h2.getName()); } } List<Human> humans = ... Collections.sort(humans, (Human h1, Human h2) ­> { h1.getName().compareTo(h2.getName()) });
5. Streams API List<Person> persons = ...; Stream tenPersonsOver18 = persons.stream() .filter(p ­> p.getAge() > 18) .limit(10); boolean isEmptyRow = csvRowEntries.stream() .allMatch(str ­> str.isEmpty()); if (isEmptyRow) { return null; }
6. Streams API // set id, location employees.stream() .filter(e ­> e.getId().equals(id)) .findFirst() .ifPresent(e ­> { e.setLocation(location); }); public List<String> getErrors() { return parseErrors.stream() .map(pe ­> pe.getMessage()) .collect(Collectors.toList()); }
7. Streams in tests // arrange // ... List<MissingEmployee> divergenceReport; List<String> missingEmployees; // act divergenceReport = service.getDivergenceReport(); missingEmployees = divergenceReport.stream() .map(MissingEmployee::getId) .collect(Collectors.toList()); // assert assertThat(missingEmployees.contains("Robert Smith"), is(true));
8. Confusions Closure Custom lambdas
9. Closures int i = 0; persons.forEach(person ­> { if ( person == null) { i++; // Error: Variable must be final or effective final } ... });
10. Custom lamdas public class Main { public static void runCalc( ??? calc) { // ??? } public static void main(String[] args) { BigDecimal a = new BigDecimal(); runCalc(a ­> a.multiply(a)); } }
11. Custom lambdas Scala def runCalc(calc: (BigInt => BigInt)) { // ??? } Java interface MyCalcLambda { BigInteger run(BigInteger input); } public static void runCalc(MyCalcLambda calc) { // ??? } public static void main(String[] args) { runCalc(a ­> a.multiply(a)); }
12. Runing custom lambdas Scala def runCalc(calc: (BigInt => BigInt)) { System.out.println(calc(10)) } Java public static void runCalc(MyCalcLambda calc) { System.out.println(calc(BigInteger.TEN)); }
13. Spring 4 with Spring boot Long story short
14. Configuration public class ServletInitializer extends SpringBootServletInitializer { @Override protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { return application.sources(Application.class); } } @Configuration @ComponentScan @EnableAutoConfiguration public class Application extends WebMvcConfigurerAdapter { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
15. start.spring.io
16. Thymeleaf
17. Primitive Maps Lists i18n config constans loops conditionals formats modules What can we put? What can we do?
18. <div th:replace="fragments/header :: header"> </div> <table> <thead> <tr> <th th:text="#{project.name}">Name</th> <th th:text="#{project.cost}">Cost</th> <th th:text="#{project.hours}">Hours</th> </tr> </thead> <tbody> <tr th:each="project : ${projects}"> <td th:text="${project.projectId}">Project ID</td> <td th:text="${#numbers.formatDecimal(project.salary, 1, 'COMMA', 2, 'POINT')}"> 1000.0 </td> <td th:text="${#numbers.formatDecimal(project.hours, 1, 'COMMA', 2, 'POINT')}"> 353 </td> </tr> </tbody> </table>
19. HTML5 way <table> <!­­/*/ <th­block data­th­each="user : ${users}"> /*/­­> <tr> <td data­th­text="${user.login}">...</td> <td data­th­text="${user.name}">...</td> </tr> <tr> <td data­th­text="${user.address}">...</td> </tr> <!­­/*/ </th­block> /*/­­> </table>
20. Gradle
21. Worries Do I need to learn groovy? Can I still use my dependencies? If my IDE supports gradle?
22. gradle hello world apply plugin: 'java' sourceCompatibility = 1.8 jar { baseName = 'demo' version = '0.0.1­SNAPSHOT' } repositories { mavenCentral() } dependencies { compile("org.springframework.boot:spring­boot­starter­web") compile("org.springframework.boot:spring­boot­starter­thymeleaf") testCompile("org.springframework.boot:spring­boot­starter­test") }
23. repositories { maven { credentials { username 'user' password 'password' } url "http://10.10.0.1/your­maven­repo" } } Custom repostiories
24. So why gradle? Clean Efficient Easily expandable with plugins
25. Front-end
26. Building front-end Modularity Dependency managment Production-ready Tests
27. Cons Many, many tools Frequent changes Pros Many, many tools Frequent changes
28. Front-end structure src ├── css ├── js dist ├── lib ├── css ├── js gulpfile.js bower.json package.json
29. Build tools demo
30. Building process What are doing when we type `gradle build`
31. gradle build 1. Compille front-end 1. Download tools with NPM 2. Download dependencies with bower 3. Build front-end with gulp 4. Pack into JAR 2. Compile the rest with front-end as a dependency
32. Questions
33. Thanks