Spring Boot submit form tutorial
last modified July 6, 2020
SpringBoot submit form tutorial shows how to submit a form in a Spring Boot application.
Spring is a popular Java application framework. Spring Boot is an effort to create stand-alone, production-grade Spring based applications with minimal effort.
Spring Boot submit form example
The following application contains a simple form. The data from a form is automatically inserted into a UI bean and is available for a view. Thymeleaf is used as a view engine.
pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ │ Application.java │ │ ├───bean │ │ │ User.java │ │ └───controller │ │ MyController.java │ └───resources │ └───templates │ addUser.html │ showMessage.html └───test └───java
This is the project structure.
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.zetcode</groupId> <artifactId>SpringBootSubmitFormEx</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.0.RELEASE</version> </parent> <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> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
This is the Maven build file. The spring-boot-starter-web
is starter for
building web, including RESTful, applications using Spring MVC.
The spring-boot-starter-thymeleaf
is a starter for the Thymeleaf engine.
When Spring locates the dependency in the pom.xml
, it automcatically configures
Thymeleaf for us.
package com.zetcode.bean; public class User { private String name; private String occupation; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getOccupation() { return occupation; } public void setOccupation(String occupation) { this.occupation = occupation; } }
This is the User
bean. It is automatically filled with data
from the form request. The attributes must match the form fields.
package com.zetcode.controller; import com.zetcode.bean.User; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; @Controller public class MyController { @GetMapping("/addUser") public String sendForm(User user) { return "addUser"; } @PostMapping("/addUser") public String processForm(User user) { return "showMessage"; } }
The controller class sends and reads a form view.
@PostMapping("/addUser") public String processForm(User user) { return "showMessage"; }
The User
bean is passed as a parameter to the
processForm()
handler. Spring tries to fill the bean
with the request data. The data is also automatically available
for the Thymeleaf showMessage
view.
package com.zetcode; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.support.SpringBootServletInitializer; @SpringBootApplication public class Application extends SpringBootServletInitializer { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
The Application
sets up the Spring Boot application
<!DOCTYPE HTML> <html xmlns:th="http://www.thymeleaf.org"> <head> <title>Add user</title> <meta charset="UTF-8"> </head> <body> <h1>Add User</h1> <form action="#" th:action="@{/addUser}" th:object="${user}" method="post"> <p> Name: <input type="text" th:field="*{name}"> </p> <p> Occupation: <input type="text" th:field="*{occupation}"> </p> <p> <input type="submit" value="Submit"/> <input type="reset" value="Reset"> </p> </form> </body> </html>
This view contains the form.
<form action="#" th:action="@{/addUser}" th:object="${user}" method="post">
The th:object
refers to the user
form bean. This is not a
class name, but a Spring bean name; therefore it is in lowercase.
<p> Name: <input type="text" th:field="*{name}"> </p>
With the *{}
syntax, we refer to the defined object.
<!DOCTYPE HTML> <html xmlns:th="http://www.thymeleaf.org"> <head> <title>Show message</title> <meta charset="UTF-8"> </head> <body> <h1>Result</h1> <p th:text="'Name: ' + ${user.name}"></p> <p th:text="'Occupation: ' + ${user.occupation}"></p> <a href="/addUser">Submit another message</a> </body> </html>
This template shows the data entered in the form.
<p th:text="'Name: ' + ${user.name}"></p>
We refer to the form bean attributes with the ${}
syntax.
Navigate to the localhost:8080/addUser
to test the application.
In this tutorial, we have shown how to submit a simple form in a Spring Boot application.