Return only string message from Spring MVC 3 Controller

Question

Can any one tell me how I can return string message from controller   If i just return a string from a controller method then spring mvc treating it as a jsp view name

User · Answer

With Spring 4  if your Controller is annotated with  RestController instead of  Controller  you don t need the  ResponseBody annotation   The code would be    RestController public class FooController        RequestMapping value   controller   method GET     public String foo           return  Response              You can find the Javadoc for  RestController here

User · Answer

ResponseBody  RequestMapping value  quot  get-text quot   produces  quot text plain quot   public String myMethod          return  quot Response  quot       You see that  ResponseBody     It s telling that the method returns some text and not to interpret it as a view etc    You see that produces  quot text plain quot      It s just a good practice as it tells what will be returned from the method

User · Answer

For outputing String as text plain use    RequestMapping value   foo   method RequestMethod GET  produces  text plain    ResponseBody public String foo         return  bar

User · Answer

Annotate your method in controller with  ResponseBody    RequestMapping value   controller   method GET   ResponseBody public String foo         return  Response        From  15 3 2 6 Mapping the response body with the  ResponseBody annotation      The  ResponseBody annotation       can be put on a method and indicates that the return type should be written straight to the HTTP response body  and not placed in a Model  or interpreted as a view name

User · Answer

This is just a note for those who might find this question later  but you don t have to pull in the response to change the content type   Here s an example below to do just that    RequestMapping method   RequestMethod GET  value   controller   public ResponseEntity lt byte   gt  displayUploadedFile       HttpHeaders headers   new HttpHeaders      String disposition   INLINE    String fileName         headers setContentType MediaType APPLICATION OCTET STREAM        Load your attachment here    if  Arrays equals Constants HEADER BYTES PDF  contentBytes         headers setContentType MediaType valueOf  application pdf         fileName      pdf          if  Arrays equals Constants HEADER BYTES TIFF BIG ENDIAN  contentBytes           Arrays equals Constantsr HEADER BYTES TIFF LITTLE ENDIAN  contentBytes         headers setContentType MediaType valueOf  image tiff         fileName      tif          if  Arrays equals Constants HEADER BYTES JPEG  contentBytes         headers setContentType MediaType IMAGE JPEG       fileName      jpg            Handle other types if necessary    headers add  Content-Disposition     disposition     filename     fileName     return new ResponseEntity lt byte   gt  uploadedBytes  headers  HttpStatus OK

User · Answer

What about   PrintWriter out   response getWriter    out println  THE STRING TO SEND AS RESPONSE    return null    This woks for me

User · Answer

Simplest solution  Just add quotes  I really don t know why it s not auto-implemented by Spring boot when response type defined as application json  but it works great   PostMapping  quot  create quot   public String foo         String result    quot something quot      return  quot   quot  quot    result    quot   quot  quot

User · Answer

Although   Tomasz is absolutely right there is another way    RequestMapping value   controller   method GET  public void foo HttpServletResponse res        try                  PrintWriter out   res getWriter            out println  Hello  world             out close          catch  IOException ex                           but the first method is preferable  You can use this method if you want to return response with custom content type or return binary type  file  etc

[java] Return only string message from Spring MVC 3 Controller

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