Spring Boot + Spring Data JPA + Thymeleaf ,Pagination & CRUD Application Example

Hello everyone, hope you are doing well. Today we will learn how to develop a simple Pagination & CRUD Application using Spring Boot, Spring Data JPA, and Thymeleaf.


Technologies Used:

  • Java 17
  • Spring Boot 2.5.5
  • Spring Data JPA
  • Thymeleaf
  • H2 Database
  • HTML
  • CSS
  • Bootstrap
  • jQuery

A little bit of Background

Thymeleaf

Thymeleaf is a modern server-side Java template engine for both web and standalone environments. 
Thymeleaf's main goal is to bring elegant natural templates to your development workflow — HTML that can be correctly displayed in browsers and also work as static prototypes, allowing for stronger collaboration in development teams. 
With modules for Spring Framework, a host of integrations with your favourite tools, and the ability to plug in your own functionality, Thymeleaf is ideal for modern-day HTML5 JVM web development — although there is much more it can do.

Spring Data JPA

Spring Data JPA provides repository support for the Java Persistence API (JPA). It eases development of applications that need to access JPA data sources.


Spring Boot

Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you can "just run". 


Let's begin,

Final Project Directory



Pom.xml

A Project Object Model or POM is the fundamental unit of work in Maven. It is an XML file that contains information about the project and configuration details utilized by Maven to build the project. 
<?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>
   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.5.5</version>
      <relativePath /> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.knf.dev.demo</groupId>
   <artifactId>spring-thymeleaf-crud-pagination</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>spring-thymeleaf-crud-pagination</name>

   <properties>
      <java.version>17</java.version>
   </properties>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-jpa</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-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>bootstrap</artifactId>
         <version>4.3.1</version>
      </dependency>
      <dependency>
         <groupId>org.webjars</groupId>
         <artifactId>jquery</artifactId>
         <version>3.4.0</version>
      </dependency>
      <dependency>
         <groupId>com.h2database</groupId>
         <artifactId>h2</artifactId>
         <scope>runtime</scope>
      </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>



Create an User Entity

The @Entity annotation specifies that the class is an entity and is mapped to a database table. 
The @Id annotation specifies the primary key of an entity and the @GeneratedValue provides for the specification of generation strategies for the values of primary keys. 
The @Column annotation is used to specify the mapped column for a persistent property or field. If no Column annotation is specified, the default value will be applied.
package com.knf.dev.demo.domain;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "_user")
public class User {

   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long id;

   @Column(name = "firstName")
   private String firstName;

   @Column(name = "lastName")
   private String lastName;

   @Column(name = "email", nullable = false, length = 200)
   private String email;

   public User() {

   }

   public Long getId() {
      return id;
   }

   public void setId(Long id) {
      this.id = id;
   }

   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 getEmail() {
      return email;
   }

   public void setEmail(String email) {
      this.email = email;
   }

   public User(String firstName, String lastName, String email) {
      this.firstName = firstName;
      this.lastName = lastName;
      this.email = email;
   }
}



Create User Repository

JpaRepository is a JPA (Java Persistence API) specific extension of Repository. It contains the full API of CrudRepository and PagingAndSortingRepository. So it contains API for basic CRUD operations and also API for pagination and sorting.
package com.knf.dev.demo.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import com.knf.dev.demo.domain.User;

@Repository
public interface UserRepository extends JpaRepository<User, Long> {

}



Create User Service

package com.knf.dev.demo.service;

import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import com.knf.dev.demo.domain.User;
import com.knf.dev.demo.exception.RecordNotFoundException;

public interface UserService {

   Page<User> findAllPageable(Pageable pageable);

   public void deleteUserById(Long id) throws RecordNotFoundException;

   public User createOrUpdateUser(User entity);

   public User getUserById(Long id) throws RecordNotFoundException;

   public List<User> getAllusers();
}



Create User Service Implementation

package com.knf.dev.demo.service.impl;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;
import com.knf.dev.demo.domain.User;
import com.knf.dev.demo.exception.RecordNotFoundException;
import com.knf.dev.demo.repository.UserRepository;
import com.knf.dev.demo.service.UserService;

@Service
public class UserServiceImpl implements UserService {

   private final UserRepository userRepository;

   public UserServiceImpl(UserRepository userRepository) {
      this.userRepository = userRepository;
   }

   @Override
   public Page<User> findAllPageable(Pageable pageable) {
      return userRepository.findAll(pageable);
   }

   @Override
   public void deleteUserById(Long id) throws RecordNotFoundException {

      Optional<User> user = userRepository.findById(id);

      if (user.isPresent()) {
         userRepository.deleteById(id);
      } else {
         throw new RecordNotFoundException("No user record exist for given id");
      }
   }

   @Override
   public User createOrUpdateUser(User entity) {
      if (entity.getId() == null) {
         entity = userRepository.save(entity);

         return entity;
      } else {
         Optional<User> user = userRepository.findById(entity.getId());

         if (user.isPresent()) {
            User newEntity = user.get();
            newEntity.setEmail(entity.getEmail());
            newEntity.setFirstName(entity.getFirstName());
            newEntity.setLastName(entity.getLastName());

            newEntity = userRepository.save(newEntity);

            return newEntity;
         } else {
            entity = userRepository.save(entity);

            return entity;
         }
      }
   }

   @Override
   public User getUserById(Long id) throws RecordNotFoundException {

      Optional<User> user = userRepository.findById(id);

      if (user.isPresent()) {
         return user.get();
      } else {
         throw new RecordNotFoundException("No user record exist for given id");
      }
   }

   @Override
   public List<User> getAllusers() {

      List<User> result = userRepository.findAll();
      if (result.size() > 0) {
         return result;
      } else {
         return new ArrayList<User>();
      }
   }
}



Create a Pager

package com.knf.dev.demo.util;

public class Pager {

   private int buttonsToShow = 3;

   private int startPage;

   private int endPage;

   public Pager(int totalPages, int currentPage, int buttonsToShow) {

      setButtonsToShow(buttonsToShow);

      int halfPagesToShow = getButtonsToShow() / 2;

      if (totalPages <= getButtonsToShow()) {
         setStartPage(1);
         setEndPage(totalPages);

      } else if (currentPage - halfPagesToShow <= 0) {
         setStartPage(1);
         setEndPage(getButtonsToShow());

      } else if (currentPage + halfPagesToShow == totalPages) {
         setStartPage(currentPage - halfPagesToShow);
         setEndPage(totalPages);

      } else if (currentPage + halfPagesToShow > totalPages) {
         setStartPage(totalPages - getButtonsToShow() + 1);
         setEndPage(totalPages);

      } else {
         setStartPage(currentPage - halfPagesToShow);
         setEndPage(currentPage + halfPagesToShow);
      }

   }

   public int getButtonsToShow() {
      return buttonsToShow;
   }

   public void setButtonsToShow(int buttonsToShow) {
      if (buttonsToShow % 2 != 0) {
         this.buttonsToShow = buttonsToShow;
      } else {
         throw new IllegalArgumentException("Must be an odd value!");
      }
   }

   public int getStartPage() {
      return startPage;
   }

   public void setStartPage(int startPage) {
      this.startPage = startPage;
   }

   public int getEndPage() {
      return endPage;
   }

   public void setEndPage(int endPage) {
      this.endPage = endPage;
   }

   @Override
   public String toString() {
      return "Pager [startPage=" + startPage + ","
            + " endPage=" + endPage + "]";
   }

}



Create RecordNotFoundException

package com.knf.dev.demo.exception;

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(value = HttpStatus.NOT_FOUND)
public class RecordNotFoundException extends Exception {

   private static final long serialVersionUID = 1L;

   public RecordNotFoundException(String message) {
      super(message);
   }

   public RecordNotFoundException
              (String message, Throwable throwable) {
      super(message, throwable);
   }
}



Create User Controller

package com.knf.dev.demo.controller;

import java.util.Optional;
import org.springframework.data.domain.PageRequest;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import com.knf.dev.demo.domain.User;
import com.knf.dev.demo.exception.RecordNotFoundException;
import com.knf.dev.demo.service.UserService;
import com.knf.dev.demo.util.Pager;

@Controller
public class UserController {

   private static final int BUTTONS_TO_SHOW = 3;
   private static final int INITIAL_PAGE = 0;
   private static final int INITIAL_PAGE_SIZE = 3;
   private static final int[] PAGE_SIZES = { 3, 6, 9, 12 };

   private final UserService service;

   public UserController(UserService service) {
      this.service = service;
   }

   @GetMapping("/")
   public ModelAndView showPersonsPage(@RequestParam("pageSize") 
       Optional<Integer> pageSize,
         @RequestParam("page") Optional<Integer> page) {

      var modelAndView = new ModelAndView("list-users");

      int evalPageSize = pageSize.orElse(INITIAL_PAGE_SIZE);

      int evalPage = page.filter(p -> p >= 1).map(p -> p - 1)
            .orElse(INITIAL_PAGE);

      var users = service.findAllPageable
            (PageRequest.of(evalPage, evalPageSize));
      var pager = new Pager(users.getTotalPages(), 
            users.getNumber(), BUTTONS_TO_SHOW);

      modelAndView.addObject("users", users);
      modelAndView.addObject("selectedPageSize", evalPageSize);
      modelAndView.addObject("pageSizes", PAGE_SIZES);
      modelAndView.addObject("pager", pager);
      return modelAndView;
   }

   @GetMapping(path = { "/addOrEdit", "/addOrEdit/{id}" })
   public String editUserById(Model model, @PathVariable("id") 
       Optional<Long> id) throws RecordNotFoundException {

      if (id.isPresent()) {
         User entity = service.getUserById(id.get());
         model.addAttribute("user", entity);
      } else {
         model.addAttribute("user", new User());
      }
      return "add-edit-user";
   }

   @GetMapping(path = "/delete/{id}")
   public String deleteUserById(Model model, 
     @PathVariable("id") Long id) 
        throws RecordNotFoundException {

      service.deleteUserById(id);
      return "redirect:/";
   }

   @PostMapping(path = "/createOrUpdateUser")
   public String createOrUpdateUser(User user) {

      service.createOrUpdateUser(user);
      return "redirect:/";
   }
}



add-edit-user.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
<meta charset="utf-8">
<meta http-equiv="x-ua-compatible" content="ie=edge">
<title>Add User</title>
<meta name="viewport" content="width=device-width, initial-scale=1">

<link rel="stylesheet"
   href="https://use.fontawesome.com/releases/v5.4.1/css/all.css">
<link rel="stylesheet"
   th:href="@{/webjars/bootstrap/4.3.1/css/bootstrap.min.css}" />
<link th:href="@{/css/style.css}" rel="stylesheet" />

</head>

<body>
   <div class="container my-5">
      <h3 th:if="${user.id != null}">Edit User</h3>
      <h3 th:if="${user.id == null}">Add User</h3>
      <div class="card">
         <div class="card-body">
            <div class="col-md-10">
               <form action="#" th:action="@{/createOrUpdateUser}"
                  th:object="${user}" method="post">
                  <div class="row">
                     <div class="form-group col-md-8">
 <label for="name" class="col-form-label"> First Name </label> <input
       type="text" th:field="*{firstName}" class="form-control"
                      id="firstName" placeholder="First Name" />
                     </div>

                     <div class="form-group col-md-8">
  <label for="name" class="col-form-label"> Last Name </label> <input
      type="text" th:field="*{lastName}" class="form-control"
                 id="lastName" placeholder="Last Name" />
                     </div>

                     <div class="form-group col-md-8">
      <label for="email" class="col-form-label"> Email </label> <input
       type="text" th:field="*{email}" class="form-control" id="email"
                       placeholder="Email Id" />
                     </div>

                     <div class="col-md-6">
    <input type="submit" class="btn btn-success" value=" Submit ">
                     </div>

                   <input type="hidden" id="id" th:field="*{id}">
                  </div>
               </form>
            </div>
         </div>
      </div>
   </div>
</body>
</html>



list-users.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
<meta charset="utf-8">
<meta http-equiv="x-ua-compatible" content="ie=edge">
<title>All Users</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet"
   href="https://use.fontawesome.com/releases/v5.4.1/css/all.css">
<link rel="stylesheet"
   th:href="@{/webjars/bootstrap/4.3.1/css/bootstrap.min.css}" />

<style>
.pagination-container {
   text-align: right;
   padding-right: 0;
}

.page-select {
   padding-left: 0;
}

.disabled {
   pointer-events: none;
   opacity: 0.5;
}

.pointer-disabled {
   pointer-events: none;
}
</style>
</head>

<body>
   <div class="container">

      <div th:switch="${users}" class="container my-5">
         <p class="my-5">
            <a href="/addOrEdit" class="btn btn-success"> <i
               class="fas fa-user-plus ml-2"> Add User </i>
            </a>
         </p>


      <select class="form-control pagination" id="pageSizeSelect">
    <option th:each="pageSize : ${pageSizes}" th:text="${pageSize}"
               th:value="${pageSize}"
               th:selected="${pageSize} == ${selectedPageSize}"></option>
         </select> <br></br>
         <div th:if="${users.totalPages != 1}">
            <ul class="pagination">
               <li th:class="${users.number == 0} ? disabled"><a
                  class="page-link"
                  th:href="@{/(pageSize=${selectedPageSize}, page=1)}">&laquo;</a></li>
               <li th:class="${users.number == 0} ? disabled"><a
                  class="page-link"
                  th:href="@{/(pageSize=${selectedPageSize}, page=${users.number})}">&larr;</a>
               </li>
               <li
                  th:class="${users.number == (page - 1)} ? 'active pointer-disabled'"
                  th:each="page : ${#numbers.sequence(pager.startPage, pager.endPage)}">
                  <a class="page-link"
                  th:href="@{/(pageSize=${selectedPageSize}, page=${page})}"
                  th:text="${page}"></a>
               </li>
               <li th:class="${users.number + 1 == users.totalPages} ? disabled">
                  <a class="page-link"
                  th:href="@{/(pageSize=${selectedPageSize}, page=${users.number + 2})}">&rarr;</a>
               </li>
               <li th:class="${users.number + 1 == users.totalPages} ? disabled">
                  <a class="page-link"
                  th:href="@{/(pageSize=${selectedPageSize}, page=${users.totalPages})}">&raquo;</a>
               </li>
            </ul>
         </div>
         <div th:case="*">
            <div class="table-responsive-xl">
               <table class="table">
                  <thead>
                     <tr>
                        <th>First Name</th>
                        <th>Last Name</th>
                        <th>Email</th>
                        <th>Edit</th>
                        <th>Delete</th>
                     </tr>
                  </thead>
                  <tbody>
                     <tr th:each="user : ${users}">
                        <td th:text="${user.firstName}"></td>
                        <td th:text="${user.lastName}"></td>
                        <td th:text="${user.email}"></td>
                        <td><a th:href="@{/addOrEdit/{id}(id=${user.id})}"
                           class="btn btn-warning"> <i class="fas fa-user-edit ml-2"></i>
                        </a></td>
                        <td><a th:href="@{/delete/{id}(id=${user.id})}"
                           class="btn btn-danger"> <i class="fas fa-user-times ml-2"></i>
                        </a></td>
                     </tr>
                  </tbody>
               </table>
            </div>
         </div>
      </div>
   </div>
   <script th:src="@{/webjars/jquery/3.4.0/jquery.min.js} "></script>
   <script th:src="@{/webjars/bootstrap/4.3.1/js/bootstrap.min.js} "></script>

   <script>
   $(document).ready(() => {
       changePageAndSize();
   });

   changePageAndSize = () => {
       $('#pageSizeSelect').change(evt => {
           window.location.replace(`/?pageSize=${evt.target.value}&page=1`);
       });
   }
   </script>

</body>
</html>



Spring Boot Main Driver

package com.knf.dev.demo;

import java.util.Arrays;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import com.knf.dev.demo.domain.User;
import com.knf.dev.demo.repository.UserRepository;

@SpringBootApplication
public class Application implements CommandLineRunner {

   @Autowired
   UserRepository repository;

   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }

   @Override
   public void run(String... args) throws Exception {

      // Insert dummy users
      User user1 = new User("Alpha", "Pro", "alpha@knf.net");
      User user2 = new User("Beta", "Pro", "beta@knf.net");
      User user3 = new User("Gama", "Gama Pro", "gama@knf.net");
      User user4 = new User("Pekka", "pekka", "pekka@knf.net");
      User user5 = new User("Tesla", "Pro", "tesla@knf.net");
      User user6 = new User("Xray", "Noob", "xray@knf.net");
      User user7 = new User("Tera", "noob", "tera@knf.net");
      User user8 = new User("Bot", "noob", "alpha@knf.net");
      User user9 = new User("Pro", "pro", "pro@knf.net");
      List<User> users = Arrays.asList(user1, user2, user3,
            user4, user9, user8, user7, user6, user5);
      repository.saveAll(users);
   }
}


Download the complete source code - click here                                        

Local Setup and Run the application

Step1: Download or clone the source code from GitHub to the local machine - Click here

Step 2: mvn clean install

Step 3: Run the Spring Boot application - mvn spring-boot:run

From the browser call the endpoint http://localhost:8080

More related topics,

Popular posts from this blog

Learn Java 8 streams with an example - print odd/even numbers from Array and List

Example 1: Java 8 program to print odd numbers from a List   import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; /*Java 8 Program to find Odd Numbers from a List*/ public class DriverClass { public static void main( String [] args) { List < Integer > numbers = Arrays. asList( 1 , 4 , 8 , 40 , 11 , 22 , 33 , 99 ); List < Integer > oddNumbers = numbers.stream(). filter(o -> o % 2 != 0 ). collect(Collectors.toList()); System.out.println(oddNumbers); } } 1. Initialize List using Arrays.asList() method. Java's built-in Arrays.asList() method converts an array into a list. This method takes an array as an argument and returns a List object. 2.  Java List interface provides stream() method which returns a sequential Stream with list of Integer as its source. 3. The Java stream filter(...
Read more

Java Stream API - How to convert List of objects to another List of objects using Java streams?

Image
In this section, we will show you how to convert a List of objects to another List of objects in Java using the Java streams map(). The ‘map’ method maps each element to its corresponding result. Java Stream API   The Java Stream API provides a functional programming approach over the object oriented capabilities of Java. It is used for processing collections of objects. The Stream in Java can be defined as a sequence of elements from a source List, Set or Array. Most of the stream operations return a Stream. This avails engender a chain of stream operations(stream pipe-lining). The streams withal support the aggregate or terminal operations on the elements. for example, finding the sum or maximum element or finding the average etc...Stream operations can either be executed sequentially or parallel. when performed parallelly, it is called a parallel stream.   Stream map() Method   The Java 8 Stream map() is an intermediate operation. It converts Stream<obj1> to Str...
Read more

Registration and Login with Spring Boot + Spring Security + Thymeleaf

Image
In this section, we will learn how to create user registration and login using Spring boot, Spring security, Thymeleaf, JPA, and H2DB. The GitHub repository link is provided at the end of this tutorial. You can download the source code. Technologies used: Spring Boot 2.5.5  Spring Data JPA  Spring Security  Thymeleaf  Maven 3+  Java 17  H2 Database   User Interface User Registration Authentication Failed Authentication success Sign out Final Project Structure: Complete 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-pare...
Read more

Java, Spring Boot Mini Project - Library Management System - Download

Image
Hello everyone, Hope you are doing well. Here, we provide a Library Management System mini-project for beginners, it's free for download. Maybe you can build more on top of this project and create your own product, that's all about you. The source code download link is provided at the end of this post. 1. Benefit of this project You could cover the following technologies and features by learning and debugging this mini project. Java 17 Java Stream Java Lamda Expressions Java Records Functional programming Object-oriented programming var Keyword in Java Generics in Java Java Switch Spring boot 2.6.4 Spring Security Thymeleaf template engine OpenCSV Spring Data JPA Server Side Pagination H2 Database  Bootstrap HTML CSS and more... 2. Objective Of Spring Boot On Library Management System The main objective of this project is to manage the details of the books, author, category, and publisher. Only Admin/Librarian will manage all these activities. Also, they can export the data in ...
Read more

ReactJS, Spring Boot JWT Authentication Example

Image
In this tutorial, we’ll create a user registration & login example using ReactJS, Spring Boot, Spring Security, and JWT authentication. You could download the source code from our Github repository, the download link is provided at the end of this tutorial. Technologies used Backend Technologies: Java 17 Spring Boot 2.7.0 Spring Security Spring Data JPA JWT H2 Database Frontend Technologies: React 17.0.1 Axios 0.27.2 Redux 4.0.5 Bootstrap 4.5.2 ReactJS - SpringBoot - JWT - Flow Backend Project Directory: Frontend Project Directory: Following is the screenshot of our application - User Registration: User Signin: Profile View: Access Resource: We will build two projects:  1. Backend:   spring-boot-security-jwt 2. Frontend: react-redux-jwt Project 1: spring-boot-security-jwt 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"...
Read more

Top 5 Java ORM tools - 2024

Image
  The term ORM refers to object-relational mapping, which uses objects to adapt programming languages to database systems while allowing them to function with SQL and object-oriented programming ideas. Any kind of database management system that can accomplish object mapping to the table in the virtual system is suitable for the implementation of ORM. Java has a wide variety of ORM tools, some of which are mentioned below: 1. Hibernate Hibernate is a lightweight, open-source, non-invasive Java ORM (Object-Relational Mapping) framework that allows developers to create objects that function independently of database software and create persistence logic in any Java or JavaEE application. It offers an abstraction layer, so developers don't have to bother about implementations; Hibernate handles these tasks internally, such as connecting to databases and creating queries to carry out CRUD operations, among other things. Persistence logic development is done with it. Persistence logic r...
Read more

Java - Blowfish Encryption and decryption Example

Image
Blowfish is an encryption method developed by Bruce Schneier in 1993 as an alternative to the DES encryption method. It is significantly faster than DES and provides good encryption speed, although no effective cryptanalysis technique has been found to date. It is one of the first secure block ciphers that is not protected by any patents and is therefore freely available for anyone to use. This is a symmetric block cipher algorithm. Block size: 64 bits Key size: variable size from 32 to 448 bits number of subsections: 18 [P-array] number of rounds: 16 number of substitution blocks: 4 [each with 512 records of 32 bits each] develop  Example 1: Encryption and decryption using Blowfish import java.io.UnsupportedEncodingException; import java.nio.charset.Charset; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.util.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSiz...
Read more

Spring boot video streaming example-HTML5

Image
Hello everyone, Today we will learn how to stream MP4 video using Spring Boot and Spring Web Flux.  The Source code download link is provided at the end of this post. New, Quarkus Practice User Interface   Project Structure: G radle(build.gradle) plugins { id 'org.springframework.boot' version '2.5.4' id 'io.spring.dependency-management' version '1.0.11.RELEASE' id 'java' } group = 'com.knf.demo' version = '0.0.1-SNAPSHOT' sourceCompatibility = '11' repositories { mavenCentral() } dependencies { implementation 'org.springframework.boot:spring-boot-starter-webflux' testImplementation 'org.springframework.boot:spring-boot-starter-test' testImplementation 'io.projectreactor:reactor-test' } test { useJUnitPlatform() } Service (VideoStreamingService.java) package  com.knf.demo.service ; import org.springframework.beans.factory.annotation. Autowired ; import org.springframework...
Read more

Google Cloud Storage + Spring Boot - File Upload, Download, and Delete

Image
In this section, we will learn  how to  create a simple spring boot application to perform different file operations such as upload, download, list, and delete files from the Google Cloud Storage. 1.  A little bit of Background Google Cloud Storage Cloud Storage is a managed service for storing unstructured data. Store any amount of data and retrieve it as often as you like. More Info - click here! Spring Boot Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you can "just run".  More Info - click here! 2. Create a GCP Project First, Sign into the Google console at  https://console.cloud.google.com . You can create a new project by first selecting the project dropdown in the top left and selecting " New Project ". Next, specify your GCP  Project name  and  Project ID . Then  Click on the " CREATE " button. Copy " Project ID " and keep it for future purposes. 3. Create a Google Cloud Storage bucke...
Read more