How to Change Context Path in Spring Boot

In a Spring Boot application, the context path is the URL prefix that is used to access the application's resources. By default, the context path is set to /, which means the application is accessible at the root URL. However, there are several ways to change the context path to suit your needs. In this tutorial, we will explore different methods to change the context path in a Spring Boot application.

Prerequisites

• JDK 17 or later
• Maven or Gradle
• IDE (IntelliJ IDEA, Eclipse, etc.)

Step 1: Set Up a Spring Boot Project

1.1 Create a New Spring Boot Project

Use Spring Initializr to create a new project with the following dependencies:

• Spring Web

Download and unzip the project, then open it in your IDE.

Step 2: Change the Context Path Using application.properties

2.1 Modify application.properties

The most straightforward way to change the context path is by modifying the application.properties file. This file is located in the src/main/resources directory.

# src/main/resources/application.properties

server.servlet.context-path=/api

Explanation:

• server.servlet.context-path=/api: Sets the context path to /api. You can change this to any desired path.

Step 3: Change the Context Path Using application.yml

3.1 Modify application.yml

If you prefer using YAML for configuration, you can change the context path by modifying the application.yml file. Create this file in the src/main/resources directory if it doesn't exist.

# src/main/resources/application.yml

server:
  servlet:
    context-path: /api

Explanation:

• server.servlet.context-path: /api: Sets the context path to /api. You can change this to any desired path.

Step 4: Change the Context Path Programmatically

4.1 Create a WebServerFactoryCustomizer Bean

You can also change the context path programmatically by creating a WebServerFactoryCustomizer bean. This approach is useful if you want to dynamically set the context path based on some condition or environment variable.

package com.example.demo;

import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ServerConfig {

    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer() {
        return factory -> factory.setContextPath("/api");
    }
}

Explanation:

• @Configuration: Marks the class as a source of bean definitions.
• WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>: Customizes the web server factory to change the context path.
• factory.setContextPath("/api"): Sets the context path to /api. You can change this to any desired path.

Step 5: Change the Context Path Using Command-Line Arguments

5.1 Run the Application with Command-Line Arguments

You can override the context path by passing a command-line argument when running the application. This method is useful for temporary changes or for running the application with different context paths in different environments without changing the code or configuration files.

./mvnw spring-boot:run -Dspring-boot.run.arguments=--server.servlet.context-path=/api

Explanation:

• -Dspring-boot.run.arguments=--server.servlet.context-path=/api: Passes the --server.servlet.context-path=/api argument to the Spring Boot application, overriding the default context path. You can change this to any desired path.

Step 6: Change the Context Path Using Environment Variables

6.1 Set Environment Variables

You can use environment variables to change the context path. This approach is useful for containerized applications or environments where you can't easily modify configuration files or command-line arguments.

export SERVER_SERVLET_CONTEXT_PATH=/api
./mvnw spring-boot:run

Explanation:

• export SERVER_SERVLET_CONTEXT_PATH=/api: Sets the SERVER_SERVLET_CONTEXT_PATH environment variable to /api.
• ./mvnw spring-boot:run: Runs the Spring Boot application, which will use the SERVER_SERVLET_CONTEXT_PATH environment variable to set the context path. You can change this to any desired path.

Step 7: Create a Simple REST Controller for Testing

To verify that the context path has been changed, let's create a simple REST controller.

package com.example.demo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello, World!";
    }
}

Explanation:

• @RestController: Marks the class as a REST controller.
• @GetMapping("/hello"): Maps GET requests to /hello to the hello method.
• hello(): Returns a simple greeting.

Step 8: Running and Testing the Application

8.1 Run the Application

Run the Spring Boot application using any of the methods mentioned above.

8.2 Test the Application

Open your browser and navigate to http://localhost:8080/api/hello (assuming you set the context path to /api). You should see the following output:

Hello, World!

Conclusion

In this tutorial, you have learned various methods to change the context path in a Spring Boot application. These methods include modifying application.properties or application.yml, using a WebServerFactoryCustomizer bean, passing command-line arguments, and setting environment variables. This flexibility allows you to configure your application to use different context paths in different environments easily.