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.

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.

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.

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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