Why would you need to configure Spring project?

Configuring enables a developer to achieve loose coupling in a project. You wouldn’t want a project to break when you need to make changes to it. For example, Honda gets its parts from different companies. Tires from Goodyear, stereo from Boss etc… But one day, Honda has a fight with Goodyear because their tires aren’t that good anymore. Now Honda needs a new company to provide tires. If the project was loosely coupled, all you have to change is the dependent(tires) and inject it into the program. So swap the tires in the configuration file with another company /*I don’t know any tire companies*/. That’s Dependency Injection!

Beans

A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. These beans are created with the configuration metadata that you supply to the container.

Configuring using Java Annotations

Java Annotations are a modern way of configuring Spring Application. They are, in short, meta-data about a class or Special labels added to Java classes. They are processed at compile time or runtime for special processing.

Examples of Java Annotations

@Override

Benefits of Java Annotations

XML configurations can be very verbose. In XML config file, every bean must be listed and if your project contains a large number of beans, it will be too much work

Spring beans can be configured using annotations

Annotations minimizes the XML configurations

Spring will scan your java classes and automatically register the bean into a spring container.

Configuring using Java code

Development Process

1. Create a java Class and annotate as @Configuration
2. Add component scanning support: @ComponentScan (Optional)
3. Read Spring Java configuration class
   SpringAnnotationContext context = new SpringAnnotationContext(SpringAnnotationApplication.class)
4. Retrieve bean from Spring container
   Use the getBean method

Defining a Bean with Java code

1. Define the methods to expose the bean by @Bean
2. Inject bean dependencies
3. Read the Spring Java Configuration class
   SpringAnnotationContext context = new SpringAnnotationContext(SpringAnnotationApplication.class)
4. Retrieve bean from Spring Container
   Use the getBean method

Auto-wiring

For dependency Injection, Spring can use spring auto wiring. The way auto-wiring works is that Spring will look for a class that matches the property.
Matchers by type: class or interface
Spring will inject the dependency automatically so you, the programmer, don’t have to worry about extra boilerplate code.

How does auto-wiring work?

• Spring will scan for @Components. The @Component is placed above the class that you want to be injected.
• Place the @Autowired above a constructor.

Spring MVC is a framework for building web application in java. It is based on Model-View-Controller design pattern.

Front Controller delegates the requests to the controller
Controller contains the business logic
1. Handle the request
2. Store/retrieve data
3. Place data in model
And finally, send it to the appropriate view template

Benefits of Spring MVC

1. Reusable UI Components
2. Flexible configuration
3. processes form data
4. Helps manage application state for web requests

What is the data format used in REST?

Mostly JSON is used but XML can also be used.

Important Things to Remember about REST

REST calls can be made over HTTP
REST is language independent which means that projects developed in any language can use APIs.

REST over HTTP

HTTP Method	CRUD Operation
POST	Creates a new entitiy
GET	Read a list of entities or a single entity
PUT	Update an existing entity
DELETE	Delete an existing entity

Where can you find REST APIs?

A good place to start is http://www.programmableweb.com. Some APIs are free while other are paid. It’s a good way to start learning.

• It stands for JavaScript Object Notation
• Its a lightweight data format for storing and exchanging data
• Language independent so it can be used with any programming language

How to write JSON?

• Curly braces define objects in JSON
• object members are name & value pairs
• Name is always in double quotes

JSON values

• Numbers: no quotes || Ex: “id”: 49
• String: double quotes || Ex: “Name” : “name”
• Boolean: true, false || Ex: “Yes”: true
• Array || Ex: “List”: [1,2,3,4]
• Nested JSON objects
• Null

Java JSON Data Binding

• Data binding is the process of converting /mapping /serializing /marshaling JSON data to a Java POJO and vice et versa.
• Spring uses Jackson project for data binding behind the scenes.
• By default, Jackson will call the appropriate getter/setter methods whenever they are called.

JSON to Java POJO

When JSON needs to be converted to Java POJO, the setter methods will be called on POJO.

Java POJO to JSON

When Java POJO needs to be converted to JSON, the getter methods will be called on POJO.

How to ignore unknown properties?

The way you ignore properties that you just added into the JSON but your program doesn’t know about is you add an annotation
@JsonIgnoreProperties(ignoreUnknown=true)

Basic Nav Classes

• nav
• nav-item
• nav-link
• nav-pills
• nav-tabs

Navbar

• bg-light
• navbar-light
• nav-link
• nav-item
• navbar-nav
• nav-brand – creates a heading for a navbar [image can be added as well]

Dropdown

Form Classes

• form-inline
• form-control

list-unstyled
list-inline-item

blockquote
blockquote-footer – for names

text-danger
bg-danger

img-fluid
img-thumbnail

float-left/right
figure-caption

container
container-fluid – the container is responsive to the viewport
row
column – splits the content into columns

section
div
/div
section

order – orders the way the colums are arraged

align-items-start ———row
align-self-start ————column
justify-content-start——row——-horizontal Alignment

position

d-flex
d-flex flex

align
align-self

Margin and Padding

Visibility

• invisible
• visible

Sizing (size-amt)

• w , h , mw , mh , vw , vh , min-vw , min-vh
• 25 , 50 , 75 , 100 , auto

Borders (side-col) & Rounded (side-shape-size)

• top , right , bottom , left
• colors
  
• top , right , bottom , left
• circle , pill
• 0 , sm , lg

Buttons

• btn-color
• btn-outline-color

Numbers

All the numbers like ints, floats, double are under the data type number in java script.
Math functions are function that can be performed by java script
For example: Math.round(number) or Math.random

Strings – Methods

Strings are an array of character, basically a word or a sentence. Many methods can be performed with Strings. Here are a few:
– myString.toUpperCase
– myString.toLowerCase

Booleans

• True
• False
• Can be used to compare Strings and Numbers

References

Keywords

var is used to declare variables

//………. or /*………/* is used for comments

All JavaScript identifiers are case sensitive. 

lower case Camel case is widely used by JavaScript programmers

Operators

+	Addition
–	Subtraction
*	Multiplication
**	Exponentiation
/	Division
%	Modulus (Division Remainder)
++	Increment
—	Decrement

JavaScript Function syntax

A JavaScript function is defined with the function keyword, followed by a name, followed by parentheses ().
Example:
function name (parameters){
Code…………………..}

Objects

var person = {
  firstName: “John”,
  lastName: “Doe”,
  age: 50,
  eyeColor: “blue”
};
Every objects has a nam

Accessing Objects in JS

objectName.propertyName or objectName[“propertyName”]
can be used to call the

References

https://www.w3schools.com/js/default.asp