What is difference between RequestBody and RequestParam

Question

I have gone through the Spring documentation to know about  RequestBody  and they have given the following explanation      The  RequestBody method parameter annotation indicates that a method parameter should be bound to the value of the HTTP request body  For example     RequestMapping value     something   method   RequestMethod PUT  public void handle  RequestBody String body  Writer writer  throws IOException     writer write body          You convert the request body to the method argument by using an HttpMessageConverter  HttpMessageConverter is responsible for converting from the HTTP request message to an object and converting from an object to the HTTP response body        DispatcherServlet supports annotation based processing using the DefaultAnnotationHandlerMapping and AnnotationMethodHandlerAdapter  In Spring 3 0 the AnnotationMethodHandlerAdapter is extended to support the  RequestBody and has the following HttpMessageConverters registered by default              but my confusion is the sentence they have written in the doc that is      The  RequestBody method parameter annotation indicates that a method parameter should be bound to the value of the HTTP request body    What do they mean by that  Can anyone provide me an example   The  RequestParam definition in spring doc is      Annotation which indicates that a method parameter should be bound to a web request parameter  Supported for annotated handler methods in Servlet and Portlet environments    I have become confused between them  Please  help me with an example on how they are different from each other

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map HTTP request header Content-Type  handle request body     RequestParam   application x-www-form-urlencoded    RequestBody   application json    RequestPart   multipart form-data       RequestParam  Spring Framework 5 1 9 RELEASE API      map to query parameters  form data  and parts in multipart requests       RequestParam is likely to be used with name-value form fields  RequestBody  Spring Framework 5 1 9 RELEASE API      bound to the body of the web request  The body of the request is passed through an HttpMessageConverter to resolve the method argument depending on the content type of the request   e g  JSON  XML   RequestPart  Spring Framework 5 1 9 RELEASE API      used to associate the part of a  multipart form-data  request      RequestPart is likely to be used with parts containing more complex content  HttpMessageConverter  Spring Framework 5 1 9 RELEASE API      a converter that can convert from and to HTTP requests and responses       All Known Implementing Classes       AbstractJsonHttpMessageConverter  AbstractXmlHttpMessageConverter

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RequestParam annotated parameters get linked to specific Servlet request parameters  Parameter values are converted to the declared method argument type   This annotation indicates that a method parameter should be bound to a web request parameter   For example Angular request for Spring RequestParam s  would look like that    http post  http   localhost 7777 scan l register username  Johny  amp password  123123  amp auth true          success function  data  status  headers  config                                                         Endpoint with RequestParam    RequestMapping method   RequestMethod POST  value     register   public Map lt String  String gt  register Model uiModel                                       RequestParam String username                                       RequestParam String password                                       RequestParam boolean auth                                      HttpServletRequest httpServletRequest          RequestBody annotated parameters get linked to the HTTP request body  Parameter values are converted to the declared method argument type using HttpMessageConverters   This annotation indicates a method parameter should be bound to the body of the web request   For example Angular request for Spring RequestBody would look like that    scope user                 username   foo               auth  true              password   bar                  http post  http   localhost 7777 scan l register    scope user                           success function  data  status  headers  config                                                                 Endpoint with RequestBody    RequestMapping method   RequestMethod POST  produces    application json                    value     register   public Map lt String  String gt  register Model uiModel                                       RequestBody User user                                      HttpServletRequest httpServletRequest          Hope this helps

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RequestParam annotation tells Spring that it should map a request parameter from the GET POST request to your method argument  For example   request   GET  http   someserver org path name John amp surname Smith   endpoint code   public User getUser  RequestParam value    name   String name                        RequestParam value    surname   String surname                      So basically  while  RequestBody maps entire user request  even for POST  to a String variable   RequestParam does so with one  or more - but it is more complicated  request param to your method argument

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It is very simple just look at their names  RequestParam it consist of two parts one is  Request  which means it is going to deal with request and other part is  Param  which itself makes sense it is going to map only the parameters of requests to java objects  Same is the case with  RequestBody it is going to deal with the data that has been arrived with request like if client has send json object or xml with request at that time  requestbody must be used

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RequestParam makes Spring to map request parameters from the GET POST request to your method argument   GET Request  http   testwebaddress com getInformation do city Sydney amp country Australia  public String getCountryFactors  RequestParam value    city   String city                        RequestParam value    country   String country       POST Request   RequestBody makes Spring to map entire request to a model class and from there you can retrieve or set values from its getter and setter methods  Check below   http   testwebaddress com getInformation do   You have JSON data as such coming from the front end and hits your controller class        city    Sydney       country    Australia      Java Code - backend   RequestBody   public String getCountryFactors  RequestBody Country countryFacts                countryFacts getCity            countryFacts getCountry            public class Country        private String city      private String country       public String getCity             return city             public void setCity String city            this city   city             public String getCountry             return country             public void setCountry String country            this country   country

User · Answer

Here is an example with  RequestBody  First look at the controller       public ResponseEntity lt Void gt  postNewProductDto  RequestBody NewProductDto newProductDto                    productService registerProductDto newProductDto           return new ResponseEntity lt  gt  HttpStatus CREATED                And here is angular controller  function postNewProductDto                     var url     admin products newItem                    http post url  vm newProductDto  then function                                    other things go here                                vm newProductMessage    Product successful registered                                                                               function  errResponse                                  handling errors                                                                   And a short look at form    lt label gt Name   lt  label gt    lt input ng-model  vm newProductDto name    gt    lt label gt Price  lt  label gt     lt input ng-model  vm newProductDto price   gt     lt label gt Quantity  lt  label gt     lt input ng-model  vm newProductDto quantity   gt     lt label gt Image  lt  label gt    lt input ng-model  vm newProductDto photo   gt     lt Button ng-click  vm postNewProductDto     gt Insert Item lt  Button gt     lt label  gt    vm newProductMessage    lt  label gt

[spring] What is difference between @RequestBody and @RequestParam?

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