Spring Boot

  • @Required: It applies to the bean setter method. It indicates that the annotated bean must be populated at configuration time with the required property, else it throws an exception BeanInitilizationException.

  • @Autowired: Spring provides annotation-based auto-wiring by providing @Autowired annotation. It is used to autowire spring bean on setter methods, instance variable, and constructor. When we use @Autowired annotation, the spring container auto-wires the bean by matching data-type.

  • @Configuration: It is a class-level annotation. The class annotated with @Configuration used by Spring Containers as a source of bean definitions.

  • @ComponentScan: It is used when we want to scan a package for beans. It is used with the annotation @Configuration. We can also specify the base packages to scan for Spring Components.

  • @Bean: It is a method-level annotation. It is an alternative of XML tag. It tells the method to produce a bean to be managed by Spring Container.

  • @Component: It is a class-level annotation. It is used to mark a Java class as a bean. A Java class annotated with @Component is found during the classpath. The Spring Framework pick it up and configure it in the application context as a Spring Bean.

  • @Controller: The @Controller is a class-level annotation. It is a specialization of @Component. It marks a class as a web request handler. It is often used to serve web pages. By default, it returns a string that indicates which route to redirect. It is mostly used with @RequestMapping annotation.

  • @Service: It is also used at class level. It tells the Spring that class contains the business logic.

  • @Repository: It is a class-level annotation. The repository is a DAOs (Data Access Object) that access the database directly. The repository does all the operations related to the database.

  • @SpringBootApplication: It is a combination of three annotations @EnableAutoConfiguration, @ComponentScan, and @Configuration.

Spring MVC and REST Annotations:

  • @RequestMapping: It is used to map the web requests. It has many optional elements like consumes, header, method, name, params, path, produces, and value. We use it with the class as well as the method.

  • @GetMapping: It maps the HTTP GET requests on the specific handler method. It is used to create a web service endpoint that fetches It is used instead of using: @RequestMapping(method = RequestMethod.GET)

  • @PostMapping: It maps the HTTP POST requests on the specific handler method. It is used to create a web service endpoint that creates It is used instead of using: @RequestMapping(method = RequestMethod.POST)

  • @PutMapping: It maps the HTTP PUT requests on the specific handler method. It is used to create a web service endpoint that creates or updates It is used instead of using: @RequestMapping(method = RequestMethod.PUT)

  • @DeleteMapping: It maps the HTTP DELETE requests on the specific handler method. It is used to create a web service endpoint that deletes a resource. It is used instead of using: @RequestMapping(method = RequestMethod.DELETE)

  • @PatchMapping: It maps the HTTP PATCH requests on the specific handler method. It is used instead of using: @RequestMapping(method = RequestMethod.PATCH)

  • @RequestBody: It is used to bind HTTP request with an object in a method parameter. Internally it uses HTTP MessageConverters to convert the body of the request. When we annotate a method parameter with @RequestBody, the Spring framework binds the incoming HTTP request body to that parameter.

  • @ResponseBody: It binds the method return value to the response body. It tells the Spring Boot Framework to serialize a return an object into JSON and XML format.

  • @PathVariable: It is used to extract the values from the URI. It is most suitable for the RESTful web service, where the URL contains a path variable. We can define multiple @PathVariable in a method.

  • @RequestParam: It is used to extract the query parameters form the URL. It is also known as a query parameter. It is most suitable for web applications. It can specify default values if the query parameter is not present in the URL.

  • @RequestHeader: It is used to get the details about the HTTP request headers. We use this annotation as a method parameter. The optional elements of the annotation are name, required, value, defaultValue. For each detail in the header, we should specify separate annotations. We can use it multiple time in a method

  • @RestController: It can be considered as a combination of @Controller and @ResponseBody annotations. The @RestController annotation is itself annotated with the @ResponseBody annotation. It eliminates the need for annotating each method with @ResponseBody.

  • @RequestAttribute: It binds a method parameter to request attribute. It provides convenient access to the request attributes from a controller method. With the help of @RequestAttribute annotation, we can access objects that are populated on the server-side.

  • @EnableSwagger2: Mainly used for documentation the Restful we-service

  • @EnableOAuth2Sso: Oauth Authentication

Boot-starter-logging:

  • internal Logger -> Apache Commons Logging

  • private final Logger LOGGER = LoggerFactory.getLogger(this.getClass());

  • spring.output.ansi.enabled - always, detect or never

  • LOGGER.info(“Simple log statement with inputs {}, {} and {}”, 1,2,3);

  • Types -> logging, log4j, logback

LOGGER.debug(“This is a debug message”);
LOGGER.info("This is an info message");
  
LOGGER.warn("This is a warn message");
  
LOGGER.error("This is an error message");

REST request validation annotations:

@AssertFalse -> 	The annotated element must be false.

@AssertTrue -> 	The annotated element must be true.

@DecimalMax -> 	The annotated element must be a number whose value must be lower or equal to the specified maximum.

@DecimalMin -> 	The annotated element must be a number whose value must be higher or equal to the specified minimum.

@Future -> 	The annotated element must be an instant, date or time in the future.

@Max -> 	The annotated element must be a number whose value must be lower or equal to the specified maximum.

@Min -> 	The annotated element must be a number whose value must be higher or equal to the specified minimum.

@Negative -> 	The annotated element must be a strictly negative number.

@NotBlank -> 	The annotated element must not be null and must contain at least one non-whitespace character.

@NotEmpty -> 	The annotated element must not be null nor empty.

@NotNull -> 	The annotated element must not be null.

@Null -> 	The annotated element must be null.

@Pattern -> 	The annotated CharSequence must match the specified regular expression.

@Positive -> 	The annotated element must be a strictly positive number.

@Size -> 	The annotated element size must be between the specified boundaries (included).

AOP annotation:

	* @Advice  
	* @before 
	* @order(0)
	* @after
	* @afterAdvice
	* @beforeReturningAdvice

Junit Test annotation:

	* @BeforeClass 
	* @Before
	* @Test
	* @After
	* @AfterClass

arious Assest Statement:

Void  equals(boolean exptation, boolean Actual)
Void  Notequals(boolean exptation, boolean Actual)
Void  assertTrue(boolean condition)
Void  assertFalse(boolean condition)
Void  assertNull(Object object)
Void  assertNotNull(Object object)
Void  assertSame(Object object1,Object object 2)
Void  assertNotSame(Object object1,Object object 2)	
void assertArrayEquals(expectedArray, resultArray);

@data in Lombok

* Will add all getter and setters 
* To string
* Equal and barcode

@NOTnull

Web App:

* request
* response
* get
* post
* jsp
* jstl
* bootstrap

Spring mvc:

* dispatcher servlet
* view resolver
* model 
* view
* validation 
* form tags

Spring Boot:

* starterss
* Autoconfiguration
* Initializr
* actuator
 	* embedded servers

External config:

MSA:

  • Collection of small autonomous
  • Small multiple services
  • All component seperate module
  • Stateless communication

Advantage:

  • easy to maintain
  • Continuous Delivery
  • Hybrid Technology -java csharp mysql
  • Cross Team coordination
  • Higher Quality code
  • Smarter Scaling
  • Risk Reduction -Seperation of services allowed for localized changes
  • Promote Big Data Best Practises
  • Improved ROI with Reduced TCO

Microservices:

  • Client Side load balancer - Ribbon

  • Distributed Tracking - Sluth and Zipkin

  • Fault Tolerance using Hystrix

  • Feign Client

  • Router and ZUUL

  • Service Registry using Eureka

  • Spring Cloud BUS

  • Spring Cloud Config

12FactorAPP-Microservices

  • Codebase = One codebase tracked in revision control, many deploys - SVN

  • Dependencies = Explicitly declare and isolate dependencies - pom.xml

  • Config = Store config in the environment - DEV ,FET , ACC

  • Backing services = Treat backing services as attached resources

  • Build, release, run = Strictly separate build and run stages

  • Processes = Execute the app as one or more stateless processes

  • Port binding = Export services via port binding

  • Concurrency = Scale out via the process model

  • Disposability = Maximize robustness with fast startup and graceful shutdown

  • Dev/prod parity = Keep development, staging, and production as similar as possibe

  • Logs = Treat logs as event streams

  • Admin processes = Run admin/management tasks as one-off processes

Properties in Spring Boot:

#MYSQL DB Properties
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/dbname
spring.datasource.username=root
spring.datasource.password=root

#JPA Properties
spring.jpa.hibernate.ddl-auto=update
spring.jpa.generate-ddl=true
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

#Eureka Properties
eureka.client.register-with-eureka=true
eureka.client.fetch-registry=true
eureak.instance.hostnam=localhost
management.endpoints.web.exposure.include=*
eureka.client.serviceUrl.defaultZone = http://localhost:8761/eureka

spring.cloud.config.uri=http://localhost:8888

spring.rabbitmq.addresses=amqps://ailhzrhf:pnHKsJmZxwUZwUh_P7wEBiiD37BrfCnQ@finch.rmq.cloudamqp.com/ailhzrhf

Server:
    Jetty
    Spring jpa mysql security 
    

security:
  oauth2:
    client:
       clientId: a48f56f893775afb1912
       clientSecret: c91036f105c04d0666655f411f716c43b606d373
       accessTokenUri: https://github.com/login/oauth/access_token
       userAuthorizationUri: https://github.com/login/oauth/authorize
       clientAuthenticationScheme: form
    resource:
      user-info-uri: https://api.github.com/user
      prefer-token-info: false