Shulou(Shulou.com)06/03 Report--

Usually, in the context of the separation of the front and rear ends, the data returned by our background service to the front end is usually formatted, such as Json. At the beginning, we use the json package to produce a string of json, together with some API of the http protocol to customize the implementation.

Spring has packaged a general processing class: ResponseEntity, which inherits from HttpEntity public class ResponseEntity extends HttpEntity {private final Object status;/** * Create a new {@ code ResponseEntity} with the given status code, and no body nor headers. * @ param status the status code * / public ResponseEntity (HttpStatus status) {this (null, null, status);} / * * Create a new {@ code ResponseEntity} with the given body and status code, and no headers. * @ param body the entity body * @ param status the status code * / public ResponseEntity (@ Nullable T body, HttpStatus status) {this (body, null, status);} and extended to deal with status codes, header,body and other data during http requests.

ResponseEntity is a generic type. Therefore, we can use any type as the response subject:

@ Controller

Public class XXXController {@ GetMapping ("/ hello") br/ > @ GetMapping ("/ hello")

Return new ResponseEntity ("Hello!", HttpStatus.OK)

}

Here is the string "Hello World!" Returned to the rest side as a string.

We can set the HTTP header:

@ GetMapping ("/ customHeader")

ResponseEntity customHeader () {

HttpHeaders headers = new HttpHeaders ()

Headers.add ("Custom-Header", "foo")

Return new ResponseEntity (

"Custom header set", headers, HttpStatus.OK)

}

Set up custom headers:

@ GetMapping ("/ customHeader")

ResponseEntity customHeader () {

Return ResponseEntity.ok ()

.header ("Custom-Header", "foo")

.body ("Custom header set")

If you put an object into:

@ GetMapping ("/ hello")

Public ResponseEntity hello () {

Return new ResponseEntity (new User ('jdon'), HttpStatus.OK)

}

The return is a JSON string:

[{'name':' jdon'}]

The following is the JSON list of the returned objects:

Public ResponseEntity repositoryProcessDefinitionsGet () {

Return new ResponseEntity (processDefRepo.findAll (), HttpStatus.FOUND)

}

The above is to manipulate the response flexibly in the code through the object ResponseEntity, but in general, we just want to return a normal response with data, so we just need to use the @ annotation

@ ResponseBody

In the case of the @ Controller annotation at the class level, the @ ResponseBody annotation tells the returned object to be automatically serialized to JSON and back to the controller's HttpResponse object.

@ Controller

Public class XXXController {

@ ResponseBody

Public User postResponseController (@ RequestBody LoginForm loginForm) {

Return new User ("Thanks For postingbacks!")

}

The client JSON string will be returned:

[{'name': Thanks For postingbacks! "}]

In the case where @ RestController annotated the class, we no longer need to use @ ResponseBody, we can simply return the object and use ResponseStatus to return the status code!

@ ResponseStatus

Although ResponseStatus only specifies the return state, it only needs to be marked on the method, which is simple, and the status code is separated from the return type, which is relatively clear. We rewrite the above code that returns the list of objects using ResponseStatus as follows, notice that the class level @ RestController:

@ RestController

Public class XXXController {

@ ResponseStatus (HttpStatus.FOUND)

Public User postResponseController () {

Return new User ("Thanks For postingbacks!")

}

This also returns the client-side JSON string:

[{'name': Thanks For postingbacks! "}]

Such code is more business-focused.

Direct manipulation response

Spring also allows us to access the javax.servlet.http.HttpServletResponse object directly; we just need to declare it as a method parameter:

@ GetMapping ("/ manual")

Public void manual (HttpServletResponse response) throws IOException {

Response.setHeader ("Custom-Header", "foo")

Response.setStatus (200)

Response.getWriter () .println ("Hello World!")

}

Because Spring provides abstraction and additional functionality on top of the underlying implementation, you will lose much of the convenience provided by Spring if you directly manipulate the response in this way.

Example code:

Import io.swagger.annotations.*

Import org.springframework.http.HttpStatus

Import org.springframework.http.ResponseEntity

Import org.springframework.web.bind.annotation.PathVariable

Import org.springframework.web.bind.annotation.RequestMapping

Import org.springframework.web.bind.annotation.RequestMethod

Import org.springframework.web.bind.annotation.RequestParam

Import javax.validation.constraints.*

@ javax.annotation.Generated (value = "io.swagger.codegen.languages.SpringCodegen", date = "2019-03-09T21:32:18.308+08:00")

@ Api (value = "tag", tags= {"tag",}, description = "the tag API")

Public interface TagApi {

@ ApiOperation (value = "get problem profile tag list", notes = "get_issue_summary_tags", response = OperateResult.class, tags= {"tag",}) @ ApiResponses (value = {@ ApiResponse (code = 200,message = "OK", response = OperateResult.class), @ ApiResponse (code = 500,message = "system error", response = Void.class)}) @ RequestMapping (value = "/ tag/ {issue_summary_key} / tags") Produces = {"application/json"}, method = RequestMethod.GET) default ResponseEntity getIssueSummaryTags (@ NotNull @ ApiParam (value = "key", required = true) @ RequestParam (value = "project_key", required = true) String projectKey, @ ApiParam (value = "issue_summary_key", required = true) @ PathVariable ("issue_summary_key") String issueSummaryKey) {/ / do some magic! Return new ResponseEntity (HttpStatus.OK) } @ ApiOperation (value = "get list of tag values for question profile", notes = "get_tag_values", response = OperateResult.class, tags= {"tag",}) @ ApiResponses (value = {@ ApiResponse (code = 200,message = "OK", response = OperateResult.class), @ ApiResponse (code = 500,message = "system error", response = Void.class) @ RequestMapping (value = "/ tag/ {issue_summary_key} / tag_value/ {tag_type}") Produces = {"application/json"}, method = RequestMethod.GET) default ResponseEntity getTagValues (@ NotNull @ ApiParam (value = "project key", required = true) @ RequestParam (value = "project_key", required = true) String projectKey, @ ApiParam (value = "issue_summary_key", required = true) @ PathVariable ("issue_summary_key") String issueSummaryKey @ ApiParam (value = "tag type app: application device: device server_name: service name level: level logger: log os: system user: user url:URL transaction: things", required = true) @ PathVariable ("tag_type") String tagType, @ NotNull @ Min (1) @ ApiParam (value = "current pages", required = true, defaultValue = "1") @ RequestParam (value = "page_number", required = true, defaultValue = "1") Integer pageNumber @ NotNull @ Min (1) @ ApiParam (value = "number of entries per page", required = true, defaultValue = "10") @ RequestParam (value = "page_size", required = true, defaultValue = "10") Integer pageSize) {/ / do some magic! Return new ResponseEntity (HttpStatus.OK);}

}

@ Controller

Public class TagApiController implements TagApi {

Private final static Logger logger = LoggerFactory.getLogger (TagApiController.class); @ Autowiredprivate TagService tagService;@Overridepublic ResponseEntity getIssueSummaryTags (@ NotNull @ ApiParam (value = "key", required = true) @ RequestParam (value = "project_key", required = true) String projectKey, @ ApiParam (value = "issue_summary_key", required = true) @ PathVariable ("issue_summary_key") String issueSummaryKey) {OperateResult operateResult = new OperateResult (); try {Preconditions.checkArgument (StringUtils.isNotBlank (projectKey)) Preconditions.checkArgument (StringUtils.isNotBlank (issueSummaryKey)); List tagValueArrayList = tagService.getIssueSummaryTagList (projectKey, issueSummaryKey); operateResult = OperateResult.success (tagValueArrayList); return new ResponseEntity (operateResult,HttpStatus.OK);} catch (Exception e) {logger.error ("api getIssueSummaryTags error. {}", e); operateResult = OperateResult.exception (OperateCode.SYSTEM_ERROR,e); return new ResponseEntity (operateResult, HttpStatus.INTERNAL_SERVER_ERROR);}}

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