Adding a Login Functionality with Spring Boot

Introduction
Understanding the Login Functionality
Implementation Steps

Setting up the Project
Adding Models and Repositories
Implementing Controllers and Views
Enhancing Security

Complete Example Code
Conclusion

Introduction

Authentication is a crucial aspect of modern web applications. This article explores the implementation of a login functionality using Java and Spring Boot, offering a secure and efficient solution for user authentication. You’ll learn how to manage user accounts, securely store credentials, and create a responsive login page.

This step-by-step guide is ideal for beginners and intermediate developers aiming to enhance their backend development skills.

Understanding the Login Functionality

The login process involves:

Verifying user credentials against a database.
Establishing a secure session.
Redirecting users to appropriate resources based on roles.

Comparison: Registration vs. Login

Feature	Registration	Login
Purpose	Create a new account	Access an existing account
Data Input	Username, password, details	Username, password
Database Operation	Insert new data	Query and validate

Implementation Steps

1. Setting up the Project

Using the provided project files, the structure already includes:

Maven dependencies in pom.xml for Spring Boot and JPA.
Basic setup for controllers and models.

2. Adding Models and Repositories

Model: Account.java

package org.studyeasy.SpringStarter.models;

import jakarta.persistence.Entity;
import jakarta.persistence.Id;

@Entity
public class Account {
    @Id
    private String username;
    private String password;
    private String role;

    // Getters and Setters
}

package org.studyeasy.SpringStarter.models;

import jakarta.persistence.Entity;

import jakarta.persistence.Id;

@Entity

public class Account {

@Id

private String username;

private String password;

private String role;

// Getters and Setters

}

Repository: AccountRepository.java

package org.studyeasy.SpringStarter.repositories;

import org.springframework.data.jpa.repository.JpaRepository;
import org.studyeasy.SpringStarter.models.Account;

public interface AccountRepository extends JpaRepository {
    Account findByUsername(String username);
}

package org.studyeasy.SpringStarter.repositories;

import org.springframework.data.jpa.repository.JpaRepository;

import org.studyeasy.SpringStarter.models.Account;

public interface AccountRepository extends JpaRepository {

Account findByUsername(String username);

}

3. Implementing Controllers and Views

Controller: AccountController.java

package org.studyeasy.SpringStarter.Controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
public class AccountController {

    @Autowired
    private AccountRepository accountRepository;

    @GetMapping("/login")
    public String loginForm(Model model) {
        return "login";
    }

    @PostMapping("/login")
    public String login(@RequestParam String username, @RequestParam String password, Model model) {
        Account account = accountRepository.findByUsername(username);
        if (account != null &amp;&amp; account.getPassword().equals(password)) {
            model.addAttribute("message", "Login successful!");
            return "home";
        }
        model.addAttribute("error", "Invalid credentials");
        return "login";
    }
}

package org.studyeasy.SpringStarter.Controller;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.*;

@Controller

public class AccountController {

@Autowired

private AccountRepository accountRepository;

@GetMapping("/login")

public String loginForm(Model model) {

return "login";

}

@PostMapping("/login")

public String login(@RequestParam String username, @RequestParam String password, Model model) {

Account account = accountRepository.findByUsername(username);

if (account != null && account.getPassword().equals(password)) {

model.addAttribute("message", "Login successful!");

return "home";

}

model.addAttribute("error", "Invalid credentials");

return "login";

}

4. Enhancing Security

Spring Security can be integrated to handle password encryption and role-based access control. This requires adding spring-security dependencies and configuring SecurityConfig.java.

Complete Example Code

The complete example is available in the provided project files. Ensure you explore:

Controllers for handling login.
View templates (HTML) for forms and responses.
Repository interfaces for database operations.

Conclusion

This article covered the fundamentals of implementing a login feature in Java using Spring Boot. By following the steps above, you’ll be able to integrate secure user authentication into your web applications.