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.