Spring Boot + Groovy Templates CRUD Example

Hello everyone, today we will learn how to develop a Spring Boot CRUD web application, using Spring Boot, Groovy template, H2DB, and Spring Data JPA.

The Groovy markup template engine provides an innovative templating system based on the builder syntax.
 
It offers various key features: 
  • hierarchical (builder) syntax to generate XML-like contents (in particular, HTML5) 
  • compilation of templates to bytecode for fast rendering
  • internationalization 
  • layout mechanism for sharing structural patterns 
  • optional type checking
and more! 


Following technologies stack being used:

  • Spring Boot 2.5.5
  • Spring MVC 5.3.10
  • Maven 3
  • JDK 11
  • Groovy templates 2.5.5
  • H2DB 
  • Bootstrap

Project Structure



Maven[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>2.5.5</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.knf.dev.demo</groupId>
   <artifactId>springjpagroovycrud</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>springjpagroovycrud</name>
   <description>Demo project for Spring Boot</description>
   <properties>
      <java.version>11</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-groovy-templates</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </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 the User Entity 

package com.knf.dev.demo.springjpagroovycrud.model;

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

    public User() {
        super();
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getFirst_name() {
        return first_name;
    }
    public void setFirst_name(String first_name) {
        this.first_name = first_name;
    }
    public String getLast_name() {
        return last_name;
    }
    public void setLast_name(String last_name) {
        this.last_name = last_name;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
}


Create User Repository

package com.knf.dev.demo.springjpagroovycrud.repository;

import com.knf.dev.demo.springjpagroovycrud.model.User;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

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


Create the User Service 

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

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import com.knf.dev.demo.springjpagroovycrud.model.User;
import com.knf.dev.demo.springjpagroovycrud.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.persistence.EntityNotFoundException;

@Service
public class UserService {
    @Autowired
    UserRepository repository;

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

    public User getUserById(Long id) throws EntityNotFoundException {
        Optional<User> user = repository.findById(id);
        if (user.isPresent()) {
            return user.get();
        } else {
            throw new EntityNotFoundException("No user record exist for given id");
        }
    }

    public User createOrUpdateUser(User entity) {
        if (entity.getId() == null) {
            entity = repository.save(entity);
            return entity;
        } else {
            Optional<User> user = repository.findById(entity.getId());
            if (user.isPresent()) {
                User newEntity = user.get();
                newEntity.setEmail(entity.getEmail());
                newEntity.setFirst_name(entity.getFirst_name());
                newEntity.setLast_name(entity.getLast_name());
                newEntity = repository.save(newEntity);
                return newEntity;
            } else {
                entity = repository.save(entity);
                return entity;
            }
        }
    }

    public void deleteUserById(Long id) throws EntityNotFoundException {
        Optional<User> user = repository.findById(id);
        if (user.isPresent()) {
            repository.deleteById(id);
        } else {
            throw new EntityNotFoundException("No user record exist for given id");
        }
    }
}



Create the User Controller 

package com.knf.dev.demo.springjpagroovycrud.controller;

import com.knf.dev.demo.springjpagroovycrud.model.User;
import com.knf.dev.demo.springjpagroovycrud.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import javax.persistence.EntityNotFoundException;
import java.util.List;

@Controller
public class UserController {

    @Autowired
    private UserService userService;
    @GetMapping("/")
    public String getAllUserView(Model model) {
        List<User> users = userService.getAllusers();
        model.addAttribute("users", users);
        return "home";
    }
    @GetMapping("/create")
    public String createUserView(Model model) {
        User user = new User();
        model.addAttribute("user", user);
        model.addAttribute("create", true);
        model.addAttribute("actionUrl", "/create");
        return "create-update";
    }
    @PostMapping("/update/{id}")
    public String createUser(@ModelAttribute("user") User user,
                             @PathVariable("id") Long id) {
        user.setId(id);
        userService.createOrUpdateUser(user);
        return "redirect:/";
    }
    @GetMapping("/update/{id}")
    public String updateUser(Model model, @PathVariable("id") Long id)
            throws EntityNotFoundException {
        User user = userService.getUserById(id);
        model.addAttribute("user", user);
        model.addAttribute("create", false);
        model.addAttribute("actionUrl",
                "/update/" + (user == null ? 0 : user.getId()) );
        return "create-update";
    }
    @PostMapping("/create")
    public String createUser(@ModelAttribute("user") User user) {
        userService.createOrUpdateUser(user);
        return "redirect:/";
    }
    @GetMapping("/delete/{id}")
    public String deleteUser(@PathVariable("id") Long id)
            throws EntityNotFoundException {
        userService.deleteUserById(id);
        return "redirect:/";
    }
}



Creating Groovy templates

home.tpl

yieldUnescaped '<!DOCTYPE html>'
html(lang: 'en') {
    head {
        meta('http-equiv': '"Content-Type" content="text/html; ' +
                'charset=utf-8"')
        title("Groovy example")
        link(rel: "stylesheet", type: "text/css",
        href: "https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css")

    }
    body {

        div(class: 'container') {
            h2("User CRUD operation with Groovy Template")
            div {
                nobr {
                    a(class: 'btn btn-primary', href: "/create", "Add User")
                }
            }
            br()
            br()
            div {
                table(class: 'table') {
                    tr {
                        th("Id")
                        th("First Name")
                        th("Last Name")
                        th("Email")
                        th("")
                        th("")
                    }
                    users.each { user ->
                        tr {
                            td("$user.id")
                            td("$user.first_name")
                            td("$user.last_name")
                            td("$user.email")
                            td {
                                a(class: 'btn btn-warning',
                                        href: "/update/$user.id", "Edit")
                            }
                            td {
                                a(class: 'btn btn-danger',
                                        href: "/delete/$user.id", "Delete")
                            }
                        }
                    }
                }
            }

        }
    }
}


create-update.tpl

yieldUnescaped '<!DOCTYPE html>'
html(lang: 'en') {
    head {
        meta('http-equiv': '"Content-Type" content="text/html; ' +
                'charset=utf-8"')
        title("Groovy example")
        link(rel: "stylesheet", type: "text/css",
        href: "https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css")
    }
    body {
        div(class: 'container') {
            if (create) {
                h1("Create a User:")
            } else {
                h1("Edit User")
            }
            a(class: 'btn btn-primary', href: "/", "Back to User List")
            br()
            br()
            form(id: "editForm", action: "$actionUrl", method: "POST") {
                table(class: 'table') {
                    if (!create) {
                        tr {
                            td("Id")
                            td(":")
                            td(user.id ?: '')
                        }
                    }
                    tr {
                        td("First Name")
                        td(":")
                        td {
                            input(name: 'first_name', type: 'text',
                                    value: user.last_name ?: '')
                        }
                    }
                    tr {
                        td("Last Name")
                        td(":")
                        td {
                            input(name: 'last_name', type: 'text',
                                    value: user.last_name ?: '')
                        }
                    }
                    tr {
                        td("Email")
                        td(":")
                        td {
                            input(name: 'email', type: 'text',
                                    value: user.email ?: '')
                        }
                    }
                }
                br()
                if (create) {
                    input(class: 'btn btn-success', type: 'submit',
                            value: 'Create')
                } else {
                    input(class: 'btn btn-success', type: 'submit',
                            value: 'Update')
                }
            }
        }
    }
}



Spring Boot Main Driver

package com.knf.dev.demo.springjpagroovycrud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringjpagroovycrudApplication {

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


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


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