Spring Boot @PathVariable

last modified July 18, 2023

Spring Boot @PathVariable tutorial shows how to read an URL template variable with @PathVariable annotation. We create a Spring Boot RESTful application to demonstrate the annotation.

Spring is a popular Java application framework and Spring Boot is an evolution of Spring which helps create stand-alone, production-grade Spring based applications easily.

@PathVariable

@PathVariable is a Spring annotation which indicates that a method parameter should be bound to a URI template variable.

It has the following optional elements:

• name - name of the path variable to bind to

• required - tells whether the path variable is required

• value - alias for name

Spring Boot @PathVariable example

The following example creates a Spring Boot web application which uses @PathVariable. The application receives an URL from which it builds a text response to the client.

build.gradle … src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ │ Application.java │ │ └───controller │ │ MyController.java │ └───resources └───test └───java

This is the project structure of the Spring Boot application.

build.gradle

plugins { id ‘org.springframework.boot’ version ‘3.1.1’ id ‘io.spring.dependency-management’ version ‘1.1.0’ id ‘java’ }

group = ‘com.zetcode’ version = ‘0.0.1-SNAPSHOT’ sourceCompatibility = ‘17’

repositories { mavenCentral() }

dependencies { implementation ‘org.springframework.boot:spring-boot-starter-web’ }

This is the Gradle build file. The spring-boot-starter-web is a starter for building web applications using Spring MVC. It uses Tomcat as the default embedded container.

com/zetcode/controller/MyController.java

package com.zetcode.controller;

import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController;

@RestController public class MyController {

@RequestMapping(path="/{name}/{age}")
public String getMessage(@PathVariable("name") String name,
                         @PathVariable("age") String age) {

    return String.format("%s is %s years old", name, age);
}

}

The controller processes the request from the client. It reads two values from the URL of the request.

@RestController public class MyController {

We have a RESTful web application.

@RequestMapping(path="/{name}/{age}") public String getMessage(@PathVariable(“name”) String name, @PathVariable(“age”) String age) {

With the @PathVariable annotation, we bind the request URL template path variable to the method variable. For instance, with the /Paul/28 URL, the Paul value is bind to the name variable, and 28 value to the age variable.

return String.format("%s is %s years old", name, age);

We build the message and return it.

com/zetcode/Application.java

package com.zetcode;

import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication public class Application {

public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
}

}

Application is the entry point which sets up Spring Boot application. The @SpringBootApplication annotation enables auto-configuration and component scanning.

$ ./gradlew bootRun

We start the Spring Boot application.

$ curl localhost:8080/Robert/39 Robert is 39 years old

We create a request to the application with the curl tool. The application responds with a message; the values were extracted from the URL with @PathVariable.

In this article we have created a RESTful web application with Spring Boot framework. We have demonstrated the usage of @PathVariable.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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