Easy Creating Simple CRUD Web Application using Grails 3

by Didin J. on Dec 22, 2016 Easy Creating Simple CRUD Web Application using Grails 3

How to creating simple create-read-update-delete (CRUD) web application step by step using Grails 3 framework.

Grails is a framework for simplifying the complicated java web development. You can find more details about Grails in here.
Don't waste our time, let's jump into a real example. Now, we are creating a web application with crud feature. Before we started, just make sure you have installed grails framework. If not installed yet, this must be a good resource for installation.

Next, open your console/terminal. Go to your projects folder then type this command to create new grails application.

grails create-app crud-webapp

It's mean to create a new application with app name "crud-webapp". Next, go to that newly created application folder.

cd crud-webapp

Type this command to enter grails interactive console.

grails

In this console type help to view all available grails command.

| Available Commands (type grails help 'command-name' for more info):
| Command Name                          Command Description
----------------------------------------------------------------------------------------------------
assemble                                Creates a JAR or WAR archive for production deployment
bug-report                              Creates a zip file that can be attached to issue reports for the current project
clean                                   Cleans a Grails application's compiled sources
compile                                 Compiles a Grails application
console                                 Runs the Grails interactive console
create-controller                       Creates a controller
create-domain-class                     Creates a Domain Class
create-functional-test                  Creates a Geb Functional Test
create-integration-test                 Creates an integration test
create-interceptor                      Creates an interceptor
create-scaffold-controller              Creates a scaffolded controller
create-script                           Creates a Grails script
create-service                          Creates a Service
create-taglib                           Creates a Tag Library
create-unit-test                        Creates a unit test
dependency-report                       Prints out the Grails application's dependencies
generate-all                            Generates a controller that performs CRUD operations and the associated views
generate-async-controller               Generates an asynchronous controller that performs CRUD operations
generate-controller                     Generates a controller that performs CRUD operations
generate-views                          Generates GSP views for the specified domain class
gradle                                  Allows running of Gradle tasks
help                                    Prints help information for a specific command
install                                 Installs a Grails application or plugin into the local Maven cache
install-templates                       Installs scaffolding templates that use f:all to render properties
list-plugins                            Lists available plugins from the Plugin Repository
open                                    Opens a file in the project
plugin-info                             Prints information about the given plugin
run-app                                 Runs a Grails application
schema-export                           Creates a DDL file of the database schema
shell                                   Runs the Grails interactive shell
stats                                   Prints statistics about the project
stop-app                                Stops the running Grails application
test-app                                Runs the applications tests
url-mappings-report                     Prints out a report of the project's URL mappings

The first step for creating CRUD web application is creating a domain (in MVC it's called Model). Just type this command.

create-domain-class com.djamware.Employee

That command will create new domain class named "Employee" inside package name "com.djamware". Edit that Employee class in folder crud-webapp/grails-app/domain/com/djamware/Employee.groovy and fill with required data fields like this.

package com.djamware

class Employee {

  String name
  String email
  String position
  Double salary
  Date created = new Date()

  static constraints = {
    email email: true
  }
}

Let me explain a little bit. This domain has 5 fields name, email, position, salary and created with different data types. Inside constraints are validation, this time the only email that has validation must be a valid email. By default, if no constraints defined, fields will be a required field.

 

Next, generate a controller and views by this command.

generate-all com.djamware.Employee

This command will create CRUD controller and views for Employee domain. Now, run your app by this command.

run-app

Open this URL http://localhost:8080 in your browser, and this is default grails view.

Grails default homepage

You see employee controller in the left bottom of the page. Just click on it and you will see this page.

Employee index page

In this CRUD page, just click "New Employee" button to create new employee data.

Employee create new form

In that employee, form fills data but don't fill as right data to test built in fields validation. Fill email with the invalid email, left the name blank and fill another data. Then click "Create" button, you will see validation works like this.

Invalid Form

Invalid Name

If you filled this form correctly data will be saved and you will see the detail of employee.

Show employee

Click on "Employee List" button to go back to employee page. You will see new data listed.

List employee

Now, you can try another CRUD function by yourself.

You might be asking how and where data saved. Yes, by default Grails 3 use the in-memory database using HSQLDB. You can find this configuration in file crud-webapp/grails-app/conf/application.yml. This line is database configuration by default using h2 or HSQL with help of hibernate as ORM or translator Object to the Database table.

hibernate:
    cache:
        queries: false
        use_second_level_cache: true
        use_query_cache: false
        region.factory_class: org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory

dataSource:
    pooled: true
    jmxExport: true
    driverClassName: org.h2.Driver
    username: sa
    password:

For different database configuration, you can change those lines.

That it's for now.

Thanks

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