What is for springMVC? Role?
For springMVC layer is a web MVC framework, is used to replace the servlet (processing | respond to the request, access to the form parameter, form validation, etc.).
Why use springMVC?
Basically, the framework is designed to simplify programming by making it easier to get form parameters, respond to requests, and so on, compared to servlets.
Describe the underlying spring MVC execution flow (how it works)
What are some common annotations used in Spring MVC?
@Controller
Identify this class as a controller
@RequestMapping
Bind a URI to the controller method
@ResponseBody
Convert the Java object into JSON and send it to the client
@RequestBody
Turn the JSON requested by the client into a Java object
@RequestParam
Do a name mapping when the form parameter and method parameter names do not match
@PathVarible
Used to get parameters in the URI, such as the value of 1 in user/1
New RESTFUL style API
@RestController
@Controller+ @ResponseBody
@GetMapping
@DeleteMapping
@PostMapping
@PutMapping
Other annotations
@SessionAttribute
What model data is declared to be stored in session
@CookieValue
Get the cookie value
@ModelAttribute
Store the method return value into the model
@HeaderValue
Gets the value in the request header
What’s the difference between SpringMVC and Strus2?
1. Different entrances:
The springMVC entry is a Servlet. The struts2 entry is filter.
2. Different life cycles:
Spring MVC Controller is singleton. So you can’t use member variables to get parameters. So high efficiency.
Struts Actions are multi-example. So you can use member variables to get parameters. So it’s inefficient.
How to implement RESTful services in Spring MVC
1. Import jackson2 package
2. Turn on annotation-driven MVC :annotation-driven/
Json interaction = @requestBody @responseBody
How does Spring MVC return JSON data
Precede the handler with the @responseBody annotation
or
Use @restController on the controller
What is an interceptor? What’s the use? How does Spring MVC define interceptors?
what:
An object similar to filter, used for pre-processing and post-processing processors (controllers).
how:
The new class
Implement HandlerInterceptor
Override three methods
preHandler
postHandler
afterCompletion
Configure interceptors in springMVC.xml
2. How to do form data verification in Spring MVC?
Environment set up
1. Configure a Validator in springMVC. XML
2,<mvc:annotation-driven validator=”validator”/>;
Add a verification rule to an Entity
@NotEmpty
@Length
.
Use BindingResult immediately after entity to receive error messages.
test(User user,BindingResult rs)
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