Spring @ModelAttribute Annotation Example
In this section we will learn about @ModelAttribute Annotation.
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public String processForm(@ModelAttribute("user") User user){
user.doStuff();
}Assume that we have a form that is backed by the User object, when the user submits the form, the values should bind to the method argument with the help of @ModelAttribute annotation.
By annotating @ModelAttribute annotation to method defines the object, which will automatically be added to the Model, and later we can use the Model object inside the view template.
@ModelAttribute("user")
public User getUser(){
return new User();
}
Here the above method will allow access to the User object in our View since it gets automatically gets added to the Models by Spring.
Methods annotated with @ModelAttribute are invoked PRIOR TO every @RequestMapping method that is invoked in the same controller class. This is generally used for populating read-only components for a form – eg the values for a select list.
The following example creates a Spring Boot web application which uses @ModelAttribute.
Project Directory
Pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.0.1</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.knf.dev.demo</groupId>
<artifactId>spring-modelattribute-example</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-modelattribute-example</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>17</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
User.java
package com.knf.dev.demo.model;
public class User {
private String firstName;
private String lastName;
private String emailId;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmailId() {
return emailId;
}
public void setEmailId(String emailId) {
this.emailId = emailId;
}
public User(String firstName, String lastName, String emailId) {
this.firstName = firstName;
this.lastName = lastName;
this.emailId = emailId;
}
}
UserController.java
package com.knf.dev.demo.controller;
import com.knf.dev.demo.model.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
@Controller
public class UserController {
@GetMapping("/user")
public String getuser () {
return "user";
}
@ModelAttribute("user")
public User user() {
return new User("Sibin", "Alpha", "sibin@gmail.com");
}
}
user.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>User</title>
</head>
<body>
First Name: <span th:text="${user.firstName}"></span><br>
Last Name: <span th:text="${user.lastName}"></span><br>
Email: <span th:text="${user.emailId}"></span>
</body>
</html>
Run Application - Application.java
mvn spring-boot:runOpen the browser and enter the following URL
http://localhost:8080/user
Download Source Code
