Spring: Microservices with Spring Boot E-Book

Ranga Rao Karanam

• Herausgeber: Packt Publishing
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 107

Veröffentlichungsjahr: 2018

Beschreibung

Unlock the power of Spring Boot to build and deploy production-ready microservices

Key Features Get to know the advanced features of Spring Boot in order to develop and monitor applications Use Spring cloud to deploy and manage microservices on the cloud Look at embedded servers and deploy a test application to a PaaS Cloud platform Embedded with assessments that will help you revise the concepts you have learned in this bookBook Description

Microservices helps in decomposing applications into small services and move away from a single monolithic artifact. It helps in building systems that are scalable, flexible, and high resilient. Spring Boot helps in building REST-oriented, production-grade microservices.

This book is a quick learning guide on how to build, monitor, and deploy microservices with Spring Boot. You'll be first familiarized with Spring Boot before delving into building microservices. You will learn how to document your microservice with the help of Spring REST docs and Swagger documentation. You will then learn how to secure your microservice with Spring Security and OAuth2. You will deploy your app using a self-contained HTTP server and also learn to monitor a microservice with the help of Spring Boot actuator.

This book is ideal for Java developers who knows the basics of Spring programming and want to build microservices with Spring Boot.

This book is embedded with useful assessments that will help you revise the concepts you have learned in this book.

What you will learn Use Spring Initializr to create a basic spring project Build a basic microservice with Spring Boot Implement caching and exception handling Secure your microservice with Spring security and OAuth2 Deploy microservices using self-contained HTTP server Monitor your microservices with Spring Boot actuator Learn to develop more effectively with developer toolsWho this book is for

This book is aimed at Java developers who knows the basics of Spring programming and want to build microservices with Spring Boot.

Ranga Rao Karanam is a programmer, trainer, and architect. His areas of interest include cloud-native applications, microservices, evolutionary design, high-quality code, DevOps, BDD, TDD, and refactoring. He loves consulting for startups on developing scalable, component-based cloud-native applications, and following modern development practices such as BDD, continuous delivery, and DevOps. He loves the freedom the Spring Framework brings to developing enterprise Java applications. Ranga started in28minutes with the vision of creating high-quality courses on developing cloud-native Java applications. He is looking forward to enhancing his already considerable success--75,000 students on Udemy and 35,000 subscribers on YouTube.

Leseprobe

Table of Contents

Spring: Microservices with Spring Boot

Credits

Meet Your Expert

Preface

What's in It for Me?

What Will I Get from This Book?

Prerequisites

1. Building Microservices with Spring Boot

What is Spring Boot?

Building a Quick Prototype for a Microservice

Primary Goals

Nonfunctional Features

Spring Boot Hello World

Configure spring-boot-starter-parent

spring-boot-starter-parent

Configure pom.xml with the Required Starter Projects

Understanding Starter Projects

Configuring spring-boot-maven-plugin

Creating Your First Spring Boot Launch Class

The SpringApplication Class

The @SpringBootApplication Annotation

Running Our Hello World Application

Auto-configuration

Starter Projects

What is REST?

First REST Service

Simple Method Returning String

Unit Testing

Integration Testing

Simple REST Method Returning an Object

Executing a Request

Unit Testing

Integration Testing

Get Method with Path Variables

Executing a Request

Unit Testing

Integration Testing

Creating a Todo Resource

Request Methods, Operations, and Uris

Beans and Services

Retrieving a Todo List

Executing the Service

Unit Testing

Integration Testing

Retrieving Details for a Specific Todo

Executing the Service

Unit Testing

Integration Testing

Adding A Todo

Postman

Executing the POST Service

Unit Testing

Integration Testing

Spring Initializr

Creating Your First Spring Initializr Project

pom.xml

FirstSpringInitializrApplication.java Class

FirstSpringInitializrApplicationTests Class

A Quick Peek into Auto-Configuration

Summary

Assessments

2. Extending Microservices

Exception Handling

Spring Boot Default Exception Handling

Non-Existent Resource

Resource Throwing an Exception

Throwing a Custom Exception

Customizing the Exception Message

Response Status

HATEOAS

Sending HATEOAS Links in Response

Spring Boot Starter HATEOAS

Validation

Enabling Validation on the Controller Method

Defining validations on the Bean

Unit Testing Validations

Documenting REST Services

Generating a Swagger Specification

Swagger UI

Customizing Swagger Documentation Using Annotations

Securing REST Services with Spring Security

Adding Spring Security Starter

Basic Authentication

Integration Testing

Unit Testing

OAuth 2 Authentication

High-level flow

Implementing OAuth 2 authentication for Our Service

Setting up Authorization and Resource Servers:

Executing OAuth Requests

Obtaining an Access Token

Executing the Request Using the Access Token

Integration Test

Internationalization

Caching

Spring-boot-starter-cache

Enabling Caching

Caching Data

JSR-107 Caching Annotations

Auto-Detection Order

Summary

Assessments

3. Advanced Spring Boot Features

Externalised Configuration

Customizing Frameworks Through application.properties

Logging

Embedded Server Configuration

Spring MVC

Spring Starter Security

Data Sources, JDBC, and JPA

Other Configuration Options

Custom Properties in Application.Properties

Configuration properties - Type-Safe Configuration Management

Profiles

Profiles-Based Bean Configuration

Other Options for Application Configuration Values

YAML Configuration

Embedded Servers

Switching to Jetty and Undertow

Building a WAR file

Developer Tools

Live Reload

Spring Boot Actuator

HAL Browser

Configuration Properties

Environment Details

Health

Mappings

Beans

Metrics

Auto-Configuration

Debugging

Deploying an Application to Cloud

Cloud Foundry

Summary

Assessments

4. Assessment Answers

Lesson 1: Building Microservices with Spring Boot

Lesson 2: Extending Microservices

Lesson 3: Advanced Spring Boot Features

Spring: Microservices with Spring Boot

Spring: Microservices with Spring Boot

Copyright © 2018 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: March 2018

Production reference: 1090318

Published by Packt Publishing Ltd.

Livery Place, 35 Livery Street

Birmingham B3 2PB, UK.

ISBN: 978-1-78913-258-8

www.packtpub.com

Credits

This book is a blend of text and quizzes, all packaged up keeping your journey in mind. It includes content from the following Packt product:

Mastering Spring 5.0 by Ranga Rao Karanam

Meet Your Expert

We have the best work of the following esteemed author to ensure that your learning journey is smooth:

Ranga Rao Karanam is a programmer, trainer, and architect. His areas of interest include cloud native applications, microservices, evolutionary design, high-quality code, DevOps, BDD, TDD, and refactoring. He loves consulting for startups on developing scalable, component-based cloud native applications, and following modern development practices such as BDD, continuous delivery, and DevOps. He loves the freedom the Spring Framework brings to developing enterprise Java applications. Ranga started in28minutes with the vision of creating high-quality courses on developing cloud native Java applications. He is looking forward to enhancing his already considerable success--75,000 students on Udemy and 35,000 subscribers on YouTube.

Preface

Nowadays developers are facing competitive pressures and it impacts the way they build applications, which includes faster delivery, scalability, and high performance. Microservices helps in decomposing applications into small services and move away from a single monolithic artifact. In that case, we can build systems that are scalable, flexible, and high resilient. Spring Boot helps in building such REST-oriented, production-grade microservices.

So, if you want to build microservices with Spring Boot, you are in the right path.

What's in It for Me?

Maps are vital for your journey, especially when you're holidaying in another continent. When it comes to learning, a roadmap helps you in giving a definitive path for progressing towards the goal. So, here you're presented with a roadmap before you begin your journey.

This book is meticulously designed and developed in order to empower you with all the right and relevant information on Spring Boot. We've created this Learning Path for you that consists of three lessons:

Lesson 1, Building Microservices with Spring Boot, covers the basics of Spring Boot and REST services. You will explore different features of Spring Boot and create a few REST services with great tests.

Lesson 2, Extending Microservices, covers how to add features such as exception handling, caching, and internationalization to your application. You will learn the best practices of documenting REST services using Swagger. You will look at the basics of securing your microservices with Spring Security.

Lesson 3, Advanced Spring Boot Features, takes a look at the advanced features in Spring Boot. You will learn how to monitor a microservice with a Spring Boot Actuator. You will then learn how to deploy the microservice to Cloud. You will also learn how to develop more effectively with the developer tools provided by Spring Boot.

What Will I Get from This Book?

Use Spring Initializr to create a basic Spring projectBuild a basic microservice with Spring BootImplement caching and exception handlingSecure your microservice with Spring security and OAuth2Deploy microservices using self-contained HTTP serverMonitor your microservices with Spring Boot actuatorLearn to develop more effectively with developer tools

Prerequisites

This book is aimed at Java developers who knows the basics of Spring programming and want to build microservices with Spring Boot. Some of the prerequisites that is required before you begin this book are:

Working knowledge on JavaBasic knowledge on Spring programming

Chapter 1. Building Microservices with Spring Boot

As we discussed in the last lesson, we are moving toward architectures with smaller, independently deployable microservices. This would mean that there will be a huge number of smaller microservices developed.

An important consequence is that we would need to be able to quickly get off the ground and get running with new components.

Spring Boot aims to solve the problem of getting off fast with a new component. In this lesson, we will start with understanding the capabilities Spring Boot brings to the table. We will answer the following questions:

Why Spring Boot?What are the features that Spring Boot provides?What is auto-configuration?What is Spring Boot not?What happens in the background when you use Spring Boot?How do you use Spring Initializr to create new Spring Boot projects?How do you create basic RESTful services with Spring Boot?

What is Spring Boot?

First of all, let's start with clearing out a few misconceptions about Spring Boot:

Spring Boot is not a code generation framework. It does not generate any code.Spring Boot is neither an application server, nor is it a web server. It provides good integration with different ranges of applications and web servers.Spring Boot does not implement any specific frameworks or specifications.

These questions still remain:

What is Spring Boot?Why has it become so popular in the last couple of years?

To answer these questions, let's build a quick example. Let's consider an example application that you want to quickly prototype.

Building a Quick Prototype for a Microservice

Let's say we want to build a microservice with Spring MVC and use JPA (with Hibernate as the implementation) to connect to the database.

Let's consider the steps in setting up such an application:

Decide which versions of Spring MVC, JPA and Hibernate to use.Set up a Spring context to wire all the different layers together.Set up a web layer with Spring MVC (including Spring MVC configuration):

Configure beans for DispatcherServlet, handler, resolvers, view resolvers, and so on

Set up Hibernate in the data layer:

Configure beans for SessionFactory, data source, and so on

Decide and implement how to store your application configuration, which varies between different environments.Decide how you would want to do your unit testing.Decide and implement your transaction management strategy.Decide and implement how to implement security.Set up your logging framework.Decide and implement how you want to monitor your application in production. Decide and implement a metrics management system to provide statistics about the application.Decide and implement how to deploy your application to a web or application server.

At least a few of the steps mentioned have to be completed before we can start with building our business logic. And this might take a few weeks at the least.

When we build microservices, we would want to make a quick start. All the preceding steps will not make it easy to develop a microservice. And that's the problem Spring Boot aims to solve.

The following quote is an extract from the Spring Boot website (http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#boot-documentation):

Spring Boot makes it easy to create stand-alone, production-grade Spring based applications that you can "just run". We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration

Spring Boot enables developers to focus on the business logic behind their microservice. It aims to take care of all the nitty-gritty technical details involved in developing microservices.

Primary Goals

The primary goals of Spring Boot are as follows:

Enable quickly getting off the ground with Spring-based projects.Be opinionated. Make default assumptions based on common usage. Provide configuration options to handle deviations from defaults.Provide a wide range of nonfunctional features out of the box.Do not use code generation and avoid using a lot of XML configuration.

Nonfunctional Features

A few of the nonfunctional features provided by Spring Boot are as follows:

Default handling of versioning and configuration of a wide range of frameworks, servers, and specificationsDefault options for application securityDefault application metrics with possibilities to extendBasic application monitoring using health checksMultiple options for externalized configuration

Spring Boot Hello World

We will start with building our first Spring Boot application in this lesson. We will use Maven to manage dependencies.

The following steps are involved in starting up with a Spring Boot application:

Configure spring-boot-starter-parent in your pom.xml file.Configure the pom.xml file with the required starter projects.Configure spring-boot-maven-plugin to be able to run the application.Create your first Spring Boot launch class.

Let's start with step 1, configuring the starter projects.

Configure spring-boot-starter-parent

Let's start with a simple pom.xml file with spring-boot-starter-parent:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mastering.spring</groupId> <artifactId>springboot-example</artifactId> <version>0.0.1-SNAPSHOT</version> <name>First Spring Boot Example</name> <packaging>war</packaging> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.0.M1</version> </parent> <properties> <java.version>1.8</java.version> </properties> <repositories> <repository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories> <pluginRepositories> <pluginRepository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </pluginRepository> </pluginRepositories> </project>

The first question is this: why do we need spring-boot-starter-parent?

A spring-boot-starter-parent dependency contains the default versions of Java to use, the default versions of dependencies that Spring Boot uses, and the default configuration of the Maven plugins.

Note

The spring-boot-starter-parent dependency is the parent POM providing dependency and plugin management for Spring Boot-based applications.

Let's look at some of the code inside spring-boot-starter-parent