Skip to main content

Posts

Spring MVC Overview

Spring MVC is a java framework that is used to build web applications. It uses  Model-View-Control design pattern and implements basic features of core spring framework such as Inversion of Control, Dependency Injection How Spring MVC works. When the client sends a request the request is captured by the Dispatcher Servlet which act as the front Controller of the system. With the help of helpers( Handler Mappings, Controller, View Resolver, View) front controller will responds the client with HTML and data. When the Dispatcher Servlet gets the request from the client, the request is immediately sent to Handler Mappings. Handler Mapping will scan the URL and will respond to the Dispatcher Servlet with address of the class that can generate data for the web page which the end user has requested.  With the respond of the Handler Mapping Dispatcher Servlet will forward the request to the Controller, so that the data will be prepared and creates a java objec...
Post a Comment
Read more
Recent posts

Overview on Struts2.

Struts2 is a popular and mature web application framework based on MVC design pattern. Struts2 is not just a new version of Struts1 but it is a complete re-write of Struts architecture. The webwork framework initially started with Struts framework as the basis and it's goal was to offer an enhance and improved framework built on Struts to make the web development easier for the developers. Architecture of Struts2 Framework. FilterDispatcher routes all the requests of the framework by acting as the "front controller" . With the use of the configured interceptors the request will be processed( pre-processing) before it is routed to the Action class. Action will take control of the request and plays the role of the "model" component..Once all the interceptors are invoked    Action class takes the responsibility to execute the business logic and returns the result that is needed to be invoked.(Action class will communicate with different classes...
Post a Comment
Read more

RESTful API

Routers can be created according to REST principles such as get, post, put, delete etc..  GET  =>  get request to r etrieve data from database or data store(An array). POST  =>  post request to insert   data to database or data store(An array). PUT  =>  put request to update the data in database or data store(An array). DELETE  =>  delete request to delete data in database or data store(An array). Creation of routers. In this scenario I have created a schema call users using mongoose.  using mongoose the created users model is retrieved. GET request  using the keyword  " get"   the data can be retrieved.  retrieving all the users in the database. By giving a parameter in the url we can get information according to the given subject.  user is retrieved according to the _id. POST request  using the keyword  "pos t"   the...
Post a Comment
Read more

What is ExpressJS

Express is a very popular framework that is used in NodeJs. Express is build upon NodeJs and also it provides a lot of tools that makes node more easy to use by adding more functionalities. Most of the needed functionalities are handled by express which helps the users to only focus on the business logic and to easily setup routes and to render the things on screen in a fast, optimized and a secured manner. How to install ExpressJS? Express can be easily installed by the command  " npm i express"  . Installation of ExpressJs package.json file will be updated once the installation is successful. How to import ExpressJS? To import the installed express module we can use the command  " require("express") " . Accessing the imported express module. express can be accessed as given below using the given commands. Firstly a constant called app is created. And then using this give constant app ...
Post a Comment
Read more

Basic commands on MongoDB.

This blog will include the basic commands on MongoDB including the  'CRUD' operations. To gain access to MongoDB open up the command prompt and run the command  'mongod'   to start the server, and open up a separate command prompt and run the command  'mongo'   to access the MongoDB. Show all the available databases. Create new database. In this example a new database called  'mycustomers'  has been created. Once a database is created and if it does not have data, that database will not be visible when   'show dbs'   command is used. Show the current working databases. To display the current working database  'db'  command is used. Since the working database is   'mycustomers' ,  'db' command results mycustomers. Adding a collection to the database. Displaying the collection of the database. Deleting the coll...
Post a Comment
Read more

Introduction to MongoDB

MongoDB is a No-SQL database. There are several types of No-SQL databases. Specifically MongoDB is a document database. All data/records are stored as documents. The data is stored using JSON (JavaScript object notation) like syntax. No-SQL databases are much different from relational databases like MYSQL where all the relations are being mapped,figuring out the exact schema including what table, fields, data type of fields is used  etc.. But in No-SQL the structure of the database/collection is planned but no need to predefined the structure before building the application. Advantages of MongoDB. High scallability.                    MongoDB is a horizontally scaled so when there is large amount of data it can be distributed to several machines. Faster.                     Since MongoDB is a document oriented database it is easy to access documents by in...
Post a Comment
Read more

Basic concepts on ReactJS

Props and State. Props and state are the two basic ways to handle data in ReactJS.  Props are used to pass data and behaviors from container components to child components. Props are read only. State is used to keep data which can be updated. State is read write enabled. State. State is basically available through  'this.state', which is by default is null. Whenever the state changes on a component the component will  automatically re-render and update DOM (Document Object Model) if there are any changes else the DOM will not get touched at all. Using state. To change the state setState() method can be used. Since setTimeOut() method is used in the bellow example after a second (1000ms)  'Will'   will be changed to  'Bob'.   Changing the state using  'setState()' If the component has an internal value that does not effect the application state is appropriate. A side from that props can be used. Props. Pro...
Post a Comment
Read more