Spring Boot 3.0 Cookbook: Proven recipes for building modern and robust Java web applications with Spring Boot

Spring Boot 3.0 Cookbook....2

Contributors....5

About the author....5

About the reviewers....5

Preface....29

Who this book is for....30

What this book covers....31

To get the most out of this book....32

Download the example code files....33

Conventions used....33

Sections....34

Getting ready....34

How to do it…....34

How it works…....35

There’s more…....35

See also....35

Get in touch....35

Share Your Thoughts....35

Download a free PDF copy of this book....35

Part 1:Web Applications and Microservices....37

Chapter 1: Building RESTful APIs....38

Technical requirements....38

Creating a RESTful API....39

Getting ready....39

How to do it.......39

How it works.......42

There’s more.......43

See also....44

Defining responses and the data model exposed by the API....44

Getting ready....44

How to do it.......44

How it works.......47

Managing errors in a RESTful API....48

Getting ready....48

How to do it.......49

How it works.......50

There’s more.......50

Testing a RESTful API....50

Getting ready....51

How to do it.......51

How it works.......53

There’s more.......53

See also....53

Using OpenAPI to document our RESTful API....54

Getting ready....54

How to do it.......54

How it works.......56

Consuming a RESTful API from another Spring Boot application using FeignClient....56

Getting ready....56

How to do it.......56

How it works.......58

There’s more.......59

Consuming a RESTful API from another Spring Boot application using RestClient....59

Getting ready....59

How to do it.......59

How it works.......60

Mocking a RESTful API....61

Getting ready....62

How to do it.......62

How it works.......63

See also....64

Chapter 2: Securing Spring Boot Applications with OAuth2....65

Technical requirements....65

Setting up Spring Authorization Server....66

Getting ready....66

How to do it…....66

How it works…....69

There’s more…....70

See also....70

Protecting a RESTful API using OAuth2....71

Getting ready....71

How to do it…....72

How it works…....74

Protecting a RESTful API using OAuth2 with different scopes....75

Getting ready....76

How to do it…....76

How it works…....78

There’s more…....78

See also....79

Configuring an MVC application with OpenID authentication....79

Getting ready....80

How to do it…....80

How it works…....89

See also....89

Logging in with Google Accounts....90

Getting ready....90

How to do it…....90

How it works…....101

See also....102

Integrating a RESTful API with a cloud IdP....103

Getting ready....103

How to do it…....103

How it works…....112

There’s more…....113

Chapter 3: Observability, Monitoring, and Application Management....117

Technical requirements....118

Adding Actuator to your application....118

Getting ready....119

How to do it…....119

How it works…....120

There’s more…....120

See also....120

Creating a custom Actuator endpoint....121

Getting ready....121

How to do it…....121

How it works…....124

Using probes and creating a custom health check....125

Getting ready....125

How to do it…....126

How it works…....129

See also....130

Implementing distributed tracing....130

Getting ready....131

How to do it…....131

How it works…....136

There’s more…....137

Accessing standard metrics....139

Getting ready....139

How to do it…....140

How it works…....142

See also....143

Creating your own metrics....143

Getting ready....144

How to do it…....144

How it works…....146

There’s more…....146

Integrating your application with Prometheus and Grafana....148

Getting ready....148

How to do it…....149

How it works…....156

Changing the settings of a running application....157

Getting ready....157

How to do it…....158

How it works…....160

There’s more…....160

Chapter 4: Spring Cloud....161

Technical requirements....161

Setting up Eureka Server....162

Getting ready....162

How to do it.......162

How it works.......164

Integrating an application in Eureka Server....164

Getting ready....164

How to do it.......164

How it works.......167

There’s more.......168

Scaling out the RESTful API....168

Getting ready....169

How to do it.......169

How it works.......171

Setting up Spring Cloud Gateway....171

Getting ready....173

How to do it.......173

How it works.......174

See also....175

Testing Spring Cloud Gateway....175

Getting ready....176

How to do it.......176

How it works.......178

Setting up Spring Cloud Config....178

Getting ready....179

How to do it.......179

How it works.......181

There’s more.......183

See also....183

Integrating distributed tracing with Spring Cloud....184

Getting ready....184

How to do it.......184

How it works.......187

Deploying Spring Boot Admin....187

Getting ready....188

How to do it.......188

How it works.......192

Protecting Spring Cloud Gateway....193

Getting ready....193

How to do it.......193

How it works.......196

Part 2: Database Technologies....197

Chapter 5: Data Persistence and Relational Database Integration with Spring Data....198

Technical requirements....199

Connecting your application to PostgreSQL....199

Getting ready....199

How to do it.......200

How it works.......202

There’s more.......202

Using JdbcClient to access the database....203

Getting ready....203

How to do it.......203

How it works.......204

Using an ORM to access the database....204

Getting ready....205

How to do it.......205

How it works.......208

There’s more.......209

See also....210

Creating the database schema from our code....210

Getting ready....210

How to do it.......210

How it works.......212

There’s more.......213

See also....213

PostgreSQL integration tests with Testcontainers....213

Getting ready....214

How to do it.......214

How it works.......215

Versioning and upgrading database schema....216

Getting ready....216

How to do it.......216

How it works.......219

There’s more.......220

See also....220

Using JPQL....221

Getting ready....221

How to do it.......221

How it works.......225

There’s more.......225

Using Native Queries....226

Getting ready....226

How to do it.......226

How it works.......228

There’s more.......229

See also....229

Updating Operations....230

Getting ready....230

How to do it.......230

How it works.......234

See also....235

Using Dynamic Queries....235

Getting ready....236

How to do it.......236

How it works.......238

There’s more.......238

See also....238

Using Transactions....239

Getting ready....239

How to do it.......239

How it works.......241

There’s more.......243

See also....243

Chapter 6: Data Persistence and NoSQL Database Integration with Spring Data....245

Technical requirements....246

Connecting your application to MongoDB....246

Getting ready....246

How to do it.......247

How it works.......250

There’s more.......251

Using Testcontainers with MongoDB....251

Getting ready....251

How to do it.......252

How it works.......253

Data indexing and sharding in MongoDB....253

Getting ready....254

How to do it.......254

How it works.......256

There’s more.......258

Using transactions in MongoDB....258

Getting ready....259

How to do it.......259

How it works.......261

See also....262

Deploying a MongoDB cluster in Testcontainers....262

Getting ready....262

How to do it.......262

How it works.......264

Managing concurrency with MongoDB....265

Getting ready....266

How to do it.......266

How it works.......267

Connecting your application to Apache Cassandra....268

Getting ready....268

How to do it.......268

How it works.......270

See also....271

Using Testcontainers with Cassandra....271

Getting ready....271

How to do it.......272

How it works.......273

Using Apache Cassandra templates....273

Getting ready....274

How to do it.......274

How it works.......275

There’s more.......276

Managing concurrency with Apache Cassandra....276

Getting ready....277

How to do it.......277

How it works.......278

Part 3: Application Optimization....279

Chapter 7: Finding Bottlenecks and Optimizing Your Application....280

Technical requirements....280

Tuning the database connection pool....281

Getting ready....281

How to do it…....282

How it works…....286

There’s more…....287

Caching dependencies....287

Getting ready....288

How to do it…....288

How it works…....290

There’s more…....290

Using shared cache....292

Getting ready....292

How to do it…....293

How it works…....294

Using Testcontainers with Redis cache....295

Getting ready....295

How to do it…....296

How it works…....296

Creating a native image using Spring Boot....297

Getting ready....297

How to do it…....297

How it works…....298

Using GraalVM Tracing Agent to configure the native application....299

Getting ready....299

How to do it…....300

How it works…....301

There’s more…....302

Creating a native executable using Spring Boot....303

Getting ready....303

How to do it…....304

How it works…....304

There’s more…....304

Creating a native executable from a JAR....305

Getting ready....306

How to do it…....306

How it works…....307

Chapter 8: Spring Reactive and Spring Cloud Stream....308

Technical requirements....309

Creating a reactive RESTful API....309

Getting ready....310

How to do it.......310

How it works.......311

There’s more.......312

Using a reactive API client....313

Getting ready....313

How to do it.......313

How it works.......315

Testing reactive applications....315

Getting ready....315

How to do it.......316

How it works.......318

Connecting to PostgreSQL using Spring Data R2DBC....319

Getting ready....319

How to do it.......320

How it works.......322

There’s more.......323

Event-driven applications with Spring Cloud Stream and RabbitMQ....324

Getting ready....324

How to do it.......325

How it works.......327

There’s more.......329

See also....330

Routing messages with Spring Cloud Stream and RabbitMQ....330

Getting ready....330

How to do it.......331

How it works.......332

See also....334

Error handling with Spring Cloud Stream....334

Getting ready....335

How to do it.......335

How it works.......338

See also....339

Part 4: Upgrading to Spring Boot 3 from Previous Versions....340

Chapter 9: Upgrading from Spring Boot 2.x to Spring Boot 3.0....341

Technical requirements....341

Preparing the application....342

Getting ready....342

How to do it.......343

How it works.......344

See also....345

Preparing Spring Security....345

Getting ready....345

How to do it.......345

How it works.......347

See also....347

Detecting property changes....348

Getting ready....348

How to do it.......348

How it works.......350

Upgrade the project to Spring Boot 3....350

Getting ready....350

How to do it.......351

How it works.......352

Upgrading Spring Data....353

Getting ready....353

How to do it.......353

How it works.......356

There’s more.......357

See also....357

Managing Actuator changes....357

Getting ready....357

How to do it.......358

How it works.......360

See also....361

Managing web application changes....361

Getting ready....362

How to do it.......362

How it works.......362

There’s more.......362

See also....363

Using OpenRewrite for migration automation....363

Getting ready....363

How to do it.......363

How it works.......367

There’s more.......367

See also....368

Index....369

Why subscribe?....385

Other Books You May Enjoy....385

Packt is searching for authors like you....389

Download a free PDF copy of this book....390

In today's dynamic landscape, crafting robust and scalable Java web applications presents formidable challenges. Spring Boot emerges as the leading framework for web and microservices development, featuring a dynamic ecosystem and seamless integrations to address a spectrum of scenarios, from scaling apps on the cloud to deploying them to production. In this book, you’ll explore its streamlined, convention-over-configuration approach, simplifying application development.

You’ll start by covering recipes showcasing Spring Boot's features. As you progress, you’ll understand how it helps streamline application development while staying ahead of technology trends. The book helps you grasp concepts effectively, explores basic REST APIs, shows you how to escalate to advanced scenarios, and tackle common cloud application challenges like security, scalability, performance optimization, and automated deployments. Dedicated sections are designed to help you stay ahead of the curve with recipes that delve into the latest trends such as containers, observability, native images, DevOps, test automation, and microservices, ensuring your applications align with evolving industry standards.

By the end of this book, you’ll be able to build and automate the deployment of a scalable and high-performing distributed solution using Spring Boot 3.

What you will learn

• Develop production-grade distributed applications
• Use various data repositories, including relational and NoSQL databases
• Implement modern testing techniques across different levels of application development
• Leveraging Testcontainers to validate all integration scenarios
• Integrate with services like Redis, PostgreSQL, MongoDB, and RabbitMQ
• Authenticate through OpenID providers
• Facilitate smooth migration from earlier Spring Boot versions

Who this book is for

This book is for Java developers who want to gain expertise in modern web development, architects designing complex systems, experienced Spring Boot developers and technology enthusiasts looking to stay up to date with the latest trends, and software engineers in need of practical solutions for everyday challenges. Hands-on experience with Java or Kotlin is required. Prior development experience on the cloud will be useful, but not necessary.