RequestParam vs PathVariable

Question

What is the difference between  RequestParam and  PathVariable while handling special characters      was accepted by  RequestParam as space    In the case of  PathVariable    was accepted as

User · Answer

it may be that the application x-www-form-urlencoded midia type convert space to    and the reciever will decode the data by converting the   to space check the url for more info http   www w3 org TR html401 interact forms html h-17 13 4 1

User · Answer

Both the annotations behave exactly in same manner   Only 2 special characters     and     are accepted by the annotations  PathVariable and  RequestParam   To check and confirm the behavior I have created a spring boot application that contains only 1 controller     RestController  public class Controller         GetMapping   pvar  pdata        public  ResponseBody String testPathVariable  PathVariable name  pdata   String pathdata                return pathdata              GetMapping   rpvar       public  ResponseBody String testRequestParam  RequestParam  param   String paramdata                return paramdata            Hitting following Requests I got the same response    localhost 7000 pvar        amp      -              lt    localhost 7000 rpvar param        amp      -              lt         was received as response in both the requests

User · Answer

PathVariable is to obtain some placeholder from the URI  Spring call it an URI Template      see Spring Reference Chapter 16 3 2 2 URI Template Patterns  RequestParam is to obtain a parameter from the URI as well     see Spring Reference Chapter 16 3 3 3 Binding request parameters to method parameters with  RequestParam   If the URL http   localhost 8080 MyApp user 1234 invoices date 12-05-2013 gets the invoices for user 1234 on December 5th  2013  the controller method would look like    RequestMapping value   user  userId  invoices   method   RequestMethod GET  public List lt Invoice gt  listUsersInvoices               PathVariable  userId   int user               RequestParam value    date   required   false  Date dateOrNull              Also  request parameters can be optional  and as of Spring 4 3 3 path variables can be optional as well  Beware though  this might change the URL path hierarchy and introduce request mapping conflicts  For example  would  user invoices provide the invoices for user null or details about a user with ID  invoices

User · Answer

RequestParam is use for query parameter static values  like  http   localhost 8080 calculation pow base 2 amp ext 4   PathVariable is use for dynamic values like   http   localhost 8080 calculation sqrt 8   RequestMapping value   pow   method RequestMethod GET  public int pow  RequestParam value  base   int base1   RequestParam value  ext   int ext1       int pow    int  Math pow base1  ext1       return pow      RequestMapping   sqrt  num    public double sqrt  PathVariable value  num   int num1       double sqrtnum Math sqrt num1       return sqrtnum

User · Answer

RequestParam annotation used for accessing the query parameter values from the request  Look at the following request URL   http   localhost 8080 springmvc hello 101 param1 10 amp param2 20   In the above URL request  the values for param1 and param2 can be accessed as below   public String getDetails       RequestParam value  param1   required true  String param1           RequestParam value  param2   required false  String param2           The following are the list of parameters supported by the  RequestParam annotation    defaultValue     This is the default value as a fallback mechanism if request is not having the value or it is empty  name     Name of the parameter to bind required     Whether the parameter is mandatory or not  If it is true  failing to send that parameter will fail  value     This is an alias for the name attribute    PathVariable   PathVariable identifies the pattern that is used in the URI for the incoming request  Let   s look at the below request URL      http   localhost 8080 springmvc hello 101 param1 10 amp param2 20   The above URL request can be written in your Spring MVC as below    RequestMapping   hello  id       public String getDetails  PathVariable value  id   String id       RequestParam value  param1   required true  String param1       RequestParam value  param2   required false  String param2               The  PathVariable annotation has only one attribute value for binding the request URI template  It is allowed to use the multiple  PathVariable annotation in the single method  But  ensure that no more than one method has the same pattern   Also there is one more interesting annotation   MatrixVariable     http   localhost 8080 spring 3 2 matrixvars stocks BT A 276 70  10 40  3 91 AZN 236 00  103 00  3 29 SBRY 375 50  7 60  2 07   And the Controller method for it    RequestMapping value      stocks    method   RequestMethod GET    public String showPortfolioValues  MatrixVariable Map lt String  List lt String gt  gt  matrixVars  Model model         logger info  Storing    Values which are       new Object     matrixVars size    matrixVars          List lt List lt String gt  gt  outlist   map2List matrixVars       model addAttribute  stocks   outlist        return  stocks         But you must enable    lt mvc annotation-driven enableMatrixVariables  true   gt

User · Answer

PathVariable - must be placed in the endpoint uri and access the query parameter value from the request  RequestParam - must be passed as method parameter  optional based on the required property   http   localhost 8080 employee call 7865467    RequestMapping value     call  callId    method   RequestMethod GET   public List lt Calls gt  getAgentCallById               PathVariable    callId   int callId               RequestParam value      status   required   false  String callStatus            http   localhost 8080 app call 7865467 status Cancelled   RequestMapping value     call  callId    method   RequestMethod GET  public List lt Calls gt  getAgentCallById               PathVariable    callId   int callId               RequestParam value      status   required   true  String callStatus

User · Answer

1   RequestParam is used to extract query parameters   http   localhost 3000 api group test id 4   GetMapping   group test   public ResponseEntity lt   gt  test  RequestParam Long id        System out println  This is test        return ResponseEntity ok   body id       while  PathVariable is used to extract data right from the URI   http   localhost 3000 api group test 4   GetMapping   group test  id    public ResponseEntity lt   gt  test  PathVariable Long id        System out println  This is test        return ResponseEntity ok   body id       2   RequestParam is more useful on a traditional web application where data is mostly passed in the query parameters while  PathVariable is more suitable for RESTful web services where URL contains values   3   RequestParam annotation can specify default values if a query parameter is not present or empty by using a defaultValue attribute  provided the required attribute is false    RestController  RequestMapping   home   public class IndexController         RequestMapping value     name       String getName  RequestParam value    person   defaultValue    John   String personName            return  Required element of request param

[java] @RequestParam vs @PathVariable

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