Скачать или смотреть How to Use Spring Tools 4 with Spring Boot, Java 11, and Tomcat 9

Learn how to configure Spring Tools 4 to work with Java 11, Tomcat 9, and Spring Boot 2.7 for your web applications.
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A Guide to Setting Up Spring Tools 4 with Spring Boot, Java 11, and Tomcat 9

When transitioning from Eclipse to Spring Tools 4 for your Spring Boot projects, you might encounter challenges, especially with configuring the right Java version and server environment. If you're asked to work with Java 11 and Tomcat 9, you may face compatibility issues when the tooling configuration defaults to newer versions. This guide aims to provide you with a practical solution so you can get started on your Spring Boot application without a hitch.

The Problem

You’re a Java developer accustomed to Eclipse, eager to create your first Spring Boot project with Spring Tools 4. However, when you go through the process of setting up a new project, you discover a few roadblocks:

Java Version Issues: The default Java version for the project is set to 17, while you need to work with Java 11.

Tomcat Configuration: You cannot find a way to configure Tomcat 9 easily from the beginning of your project setup.

Runtime Exceptions: After making manual adjustments to the configuration, you receive errors indicating that the Spring Boot version doesn’t match your specified Java runtime.

Understanding the Configuration Requirements

Before we dive into the solution, it’s crucial to understand the constraints surrounding Spring Boot versions and their Java compatibility:

Spring Boot 3 requires Java 17 as a minimum, which means using it would not align with your requirement for Java 11.

Tomcat Compatibility: If you specifically need Tomcat 9.0.31, you need to explicitly include it in your project setup.

The Solution: Steps to Create Your Project with Spring Tools 4

To successfully configure Spring Tools 4 for your Spring Boot project using Java 11 and Tomcat 9, follow the outlined steps below:

1. Create a New Project

Start by launching Spring Tools 4.

Select File New Spring Starter Project.

2. Configuration of Project Properties

When you reach the project setup wizard, modify the settings as follows:

Project Type: Select Maven as the build system.

Java Version: Choose Java 11 from the dropdown (Note: If this option is not available, continue with the next steps and adjust it later).

Packaging: Set the packaging type to WAR.

3. Specifying Spring Boot Version

Ensure you select the latest Spring Boot version compatible with Java 11, which is Spring Boot 2.7.

4. Manually Update Project Settings (If Necessary)

If the project still defaults to Java 17 after setup, you'll have to make several manual updates:

Navigate to Window Preferences Java and set Compiler compliance level to 11.

Under Installed JREs, replace the JDK with your JDK 11 installation path.

Go to Server Runtime Environments and add Tomcat 9.0.31.

5. Update Project Facets and Build Path

Access your project settings:

In Project Properties Java Build Path, ensure the Java version is set to JDK 11.

Under Project Facets, confirm that the Java version is also set to 11.

6. Configure pom.xml

Make sure to specify the Java version in your pom.xml file:

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After all updates, perform a Clean Project and Update Maven Project.

7. Building and Running the Application

With everything configured properly, go to the Boot Dashboard and attempt to start your demo project again. If everything is set, it should now run successfully without throwing errors related to Java versions.

Conclusion

By carefully selecting the appropriate versions of Spring Boot and manually configuring your project settings, you’ll be able to run your Spring Boot application using Java 11 and Tomcat 9 without issues. If you find that issues persist, double-check each setting to ensure there are no conflicts or omissions in