@Summary of ResponseBody annotation

[email protected] The role of annotations

      @ResponseBody yes spring The annotations in , The annotation has no parameters ,@ResponseBody The main function of annotation is to Controller The method returns the object , After converting to the specified format through the converter , Write to HTTP response body in , Usually used to return JSON Data or xml data .

[email protected] Where is it used

      @ResponseBody Annotations are generally used in Controller On the way ; It can also be used throughout Controller On , On behalf of the entire Controller The methods in @ResponseBody To convert data , If it works on the whole Controller You can talk to @Controller The annotations are merged into @RestController Annotation to use .

      @ResponseBody Annotations will also play ajax Request the function of the end identifier , When ajax The request will not end until the annotation is obtained from the stream , Continue to run the program downward .

[email protected] Analysis of annotation

      Used in method @RequestMapping When annotating , The return value of the method usually resolves to the path of the jump , That is, you need to jump to the specified page . When added @ResponseBody After this annotation , It indicates that the return value of this method is written directly to HTTP Response Body in [email protected] You can label any object , from Srping Complete the conversion of objects and protocols .

      If the input parameter is a string, write the string directly to the client , If the input parameter is an object , The object is converted to json The string is then written to the client . What needs to be noted here is , If you return an object , Press utf-8 code . If you return String, Press default iso8859-1 code , The page may be garbled . Therefore, in the annotation, we can manually modify the encoding format , for example @RequestMapping(value="/cat/query",produces="text/html;charset=utf-8"), In front of this is the requested path , Followed by the encoding format .

      @ResponseBody Let in the annotation Controller The return value of the control layer method is converted to json The format string is through HttpMessageConverter Methods in realize the transformation of classes . If it is an input parameter, it is bean object , Will call the object getXXX（） Method to obtain the property value and encapsulate it in the form of key value pairs , And into json character string . If the input parameter is map aggregate , Will use get(key) How to get value value , And then encapsulate it , And then encapsulate it on the formal parameter .

      That's all @ResponseBody Summary of relevant knowledge of annotation , Continue to work hard , come on. ~~~