From 9b3396e2b5cb3660a94fb4a4c0dfb873b46ce224 Mon Sep 17 00:00:00 2001
From: Kamal Wickramanayake <kamal@inbox.lk>
Date: Sat, 6 Jun 2026 20:02:35 +0530
Subject: Added a Spring Boot + Thymeleaf based form validation sample
 application code

---
 .../06-form-handling-with-thymeleaf/.gitignore     |  2 +
 .../06-form-handling-with-thymeleaf/pom.xml        | 28 ++++++++++++++
 .../main/java/com/example/spring/Application.java  | 12 ++++++
 .../java/com/example/spring/HomeController.java    | 13 +++++++
 .../example/spring/contact/ContactController.java  | 36 +++++++++++++++++
 .../com/example/spring/contact/ContactForm.java    | 45 ++++++++++++++++++++++
 .../src/main/resources/application.properties      |  0
 .../src/main/resources/templates/contact/form.html | 36 +++++++++++++++++
 .../main/resources/templates/contact/result.html   | 16 ++++++++
 .../src/main/resources/templates/index.html        | 18 +++++++++
 10 files changed, 206 insertions(+)
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/.gitignore
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/pom.xml
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/Application.java
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/HomeController.java
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactController.java
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactForm.java
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/resources/application.properties
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/form.html
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/result.html
 create mode 100644 spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/index.html

(limited to 'spring-boot')

diff --git a/spring-boot/06-form-handling-with-thymeleaf/.gitignore b/spring-boot/06-form-handling-with-thymeleaf/.gitignore
new file mode 100644
index 0000000..3df278e
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/.gitignore
@@ -0,0 +1,2 @@
+target
+.vscode
diff --git a/spring-boot/06-form-handling-with-thymeleaf/pom.xml b/spring-boot/06-form-handling-with-thymeleaf/pom.xml
new file mode 100644
index 0000000..c486563
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/pom.xml
@@ -0,0 +1,28 @@
+<?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>com.example.spring.boot</groupId>
+		<artifactId>base-config</artifactId>
+		<version>0.0.1-SNAPSHOT</version>
+		<relativePath>../00-config</relativePath>
+	</parent>
+
+	<artifactId>form-handling-with-thymeleaf</artifactId>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-thymeleaf</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-validation</artifactId>
+		</dependency>
+	</dependencies>
+
+</project>
\ No newline at end of file
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/Application.java b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/Application.java
new file mode 100644
index 0000000..4393f3f
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/Application.java
@@ -0,0 +1,12 @@
+package com.example.spring;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+	public static void main(String[] args) throws Exception {
+		SpringApplication.run(Application.class, args);
+	}
+}
\ No newline at end of file
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/HomeController.java b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/HomeController.java
new file mode 100644
index 0000000..d6ead56
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/HomeController.java
@@ -0,0 +1,13 @@
+package com.example.spring;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+public class HomeController {
+
+    @RequestMapping("/")
+	public String home() {
+		return "index";
+	}
+}
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactController.java b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactController.java
new file mode 100644
index 0000000..1a61a39
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactController.java
@@ -0,0 +1,36 @@
+package com.example.spring.contact;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+
+import jakarta.validation.Valid;
+
+@Controller
+public class ContactController {
+
+	@GetMapping("/contact")
+	public String showForm(Model model) {
+		model.addAttribute("contactForm", new ContactForm());
+		return "contact/form";
+	}
+
+	@PostMapping("/contact")
+	public String processSubmission(@Valid @ModelAttribute ContactForm contactForm, BindingResult bindingResult,
+			Model model) {
+		if (bindingResult.hasErrors()) {
+			return "contact/form";
+		}
+
+		// Do whatever needed with the submitted data here.
+		// For example, invoke a method in a service/componet bean to send an email to contact person.
+
+		model.addAttribute("contactForm", contactForm);
+
+		return "contact/result";
+	}
+
+}
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactForm.java b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactForm.java
new file mode 100644
index 0000000..c641edf
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/java/com/example/spring/contact/ContactForm.java
@@ -0,0 +1,45 @@
+package com.example.spring.contact;
+
+import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Size;
+
+public class ContactForm {
+
+	@Pattern(regexp = "^[ a-zA-Z]+$", message = "Name should only include English letters")
+	@NotBlank(message = "Name is required")
+	private String name;
+
+	@Email(message = "Must be a valid email")
+    @NotBlank(message = "Email is required")
+	private String email;
+
+	@Size(min = 10, message = "Message must be at least 10 characters long")
+	private String message;
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getEmail() {
+		return email;
+	}
+
+	public void setEmail(String email) {
+		this.email = email;
+	}
+
+	public String getMessage() {
+		return message;
+	}
+
+	public void setMessage(String message) {
+		this.message = message;
+	}
+
+}
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/application.properties b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/application.properties
new file mode 100644
index 0000000..e69de29
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/form.html b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/form.html
new file mode 100644
index 0000000..0229e0d
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/form.html
@@ -0,0 +1,36 @@
+<!DOCTYPE HTML>
+<html xmlns:th="http://www.thymeleaf.org">
+
+<head>
+    <title>Contact Us</title>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+</head>
+
+<body>
+    <h1>Contact Us</h1>
+
+    <form th:action="@{/contact}" th:object="${contactForm}" method="post">
+        <div>
+            <label>Name</label>
+            <input type="text" th:field="*{name}" placeholder="Your name" />
+            <div th:if="${#fields.hasErrors('name')}" th:errors="*{name}"></div>
+        </div>
+
+        <div>
+            <label>Email</label>
+            <input type="email" th:field="*{email}" placeholder="Your email" />
+            <div th:if="${#fields.hasErrors('email')}" th:errors="*{email}"></div>
+        </div>
+
+        <div>
+            <label>Message</label>
+            <textarea th:field="*{message}" placeholder="Your message"></textarea>
+            <div th:if="${#fields.hasErrors('message')}" th:errors="*{message}"></div>
+        </div>
+
+        <button type="submit">Send</button>
+    </form>
+
+</body>
+
+</html>
\ No newline at end of file
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/result.html b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/result.html
new file mode 100644
index 0000000..1bb4b45
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/contact/result.html
@@ -0,0 +1,16 @@
+<!DOCTYPE HTML>
+<html xmlns:th="http://www.thymeleaf.org">
+<head>
+    <title>Contact Us</title>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+</head>
+<body>
+	<h1>Contact Us</h1>
+    
+    <p>We received your message.</p>
+
+    <p th:text="'Thank you ' + ${contactForm.name} + '.'" />
+
+    <a href="/contact">Try again</a>
+</body>
+</html>
\ No newline at end of file
diff --git a/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/index.html b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/index.html
new file mode 100644
index 0000000..48e251d
--- /dev/null
+++ b/spring-boot/06-form-handling-with-thymeleaf/src/main/resources/templates/index.html
@@ -0,0 +1,18 @@
+<!DOCTYPE HTML>
+<html xmlns:th="http://www.thymeleaf.org">
+
+<head>
+    <title>Form handling example with Thymeleaf</title>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+</head>
+
+<body>
+
+<h1>Form handling example with Thymeleaf</h1>
+
+<a href="/contact">Contact Us</a>
+
+</body>
+
+</html>
+
-- 
cgit v1.2.3