Shulou(Shulou.com)06/01 Report--

The main content of this article is to explain "what notes are there in Spring to declare bean". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Now let the editor to take you to learn "what are the annotations and statements of Spring bean"!

Bean comments

Spring provides several annotations declaring that bean is a Bean managed by Spring

@ Controller declares such things as a MVC class, which is usually used with @ RequestMapping

@ Service declares that this class is a business processing class, usually used with @ Transactional

@ Component General comment

@ Repository database operation

@ RestController to develop rest api

ResponseBody

The @ responseBody function is to convert the object returned by the controller method to the specified format through an appropriate converter, and then write it to the body area of the response object, which is usually used to return JSON data or XML.

Http://localhost:8080/responsebody

@ ResponseBody @ RequestMapping ("/ responseBody") public String responseBody () {return "hello springmvc";} RequestParam

Pass the parameter with the specified name in the request to the parameter assignment in the controller

Attributes:

Value: the name in the request parameter

Required: whether this parameter must be provided in the request parameters. The default value is true, and must be provided.

Http://localhost:8080/param?id=111

@ ResponseBody @ RequestMapping ("/ param") public String requestParam (@ RequestParam (value = "id", required = false) String userId) {return "hello" + userId;} RequestBody

Get the content of the request parameter. Because the get method has no body, all get cannot be used.

Attribute required: whether there must be a request body. The default is true.

@ ResponseBody @ RequestMapping (value = "/ requestBody", method = RequestMethod.POST) public String requestBody (@ RequestBody String body) {return body;}

Curl Test request Post

PathVariable

That owns a placeholder in the binding url. / delete/ {id}, {id} is a placeholder

Attribute value: specifies the placeholder name in url

RequestHeader

Gets the value of the specified request header

Attribute value: name of the request header

CookieValue

Gets the value of the name of the specified cookie

The name of the property value:cookie

ModelAttribute

Appears on the method: indicates that the current method will be executed on the front line of the controller method execution.

Appears on the parameter: gets the specified data to assign to the parameter.

Application scenarios:

1 when the submitted form data is not complete physical data, make sure that the unsubmitted fields use the original data of the database.

2 the modified method does not return a value

SessionAttributes

Parameter sharing among multiple execution controller methods

Attribute 1. Value: specifies the name of the stored attribute

At this point, I believe that you have a deeper understanding of the "Spring comments declaration bean", might as well come to the actual operation! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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