spring mvc

spring mvc

1. definition

   • build software on top of Model-view controller architecture
     • View
       • can use JSP
       • use a view resolver to identify what JSP should handle a specific request
         • can use prefix to define a path
         • can use a suffix to define a format (.jsp)
         • resolver view must be specified inside "web.xml"
       • organization
         • should be stored inside "WEB-INF"
       • chaining
         • can chain views, through the controller using "forward" or "redirect"
       • tags
         • make interacting with data easier in our pages
         • types
           • spring.tld
             • evaluating error
             • setting themes
             • outputting internationalized messages
           • spring-form.tld
             • based around proccessing form data
             • most of its tag are mirrored from html form tag
       • interceptor
         • are part of the request life cycle. Trigered when goes to or goes from controller
         • used to perform actions before or after handling, or after completion of a request
         • spring allow to create our interceptor or use existing ones, like the Locale Changing(to change lenguage)

2. web.xml

   • here the view resolvers are configured
     • contains the directory where JSPs are storaged
       • needed information to map successfully request and JSP
     • also, can configure them to retrieve static resorces as pdf

3. components of architecture

   • @Controller
     • handle incoming request and building the response
     • gateway to bussiness logic tier
     • determine the view to show the data according to the returned model
     • annotation
       • @Controller
       • @RequestMapping
     • @ModelAttribute
       • used whenever we want to send data to the controller or retrive data from the controller
       • Binding result
     • can forward a request
       • also can redirect a request (creates a new one, so the state on the current one vanish)
   • @Service
     • contain bussiness logic (describes the verbs)
     • ensures bussiness object is in a valid state
     • transactions often begin
   • @Repository (DAO)
     • Mapping with DB or and object
     • focused on persisting and interacting with DB (focused on nouns)

4. validation

   • can use the JSR 303
     • validation standard in the Java (vanilla )world. Bean validation API provides an object level constraint declaration and validation facility for the Java application developer
     • requeriments
       • import hibernate-validator dependency
       • Specify in your model the validation rules
       • in your controller, identify if exist an error and handle it
         • have to use BindingResult (boolean)

5. features

   • built-in support to RESTFUL
   • Multiple view resolvers to support
     • xml
     • json
     • html

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