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.
This question is related to
java
spring
spring-mvc
For outputing String
as text/plain
use:
@RequestMapping(value="/foo", method=RequestMethod.GET, produces="text/plain")
@ResponseBody
public String foo() {
return "bar";
}
What about:
PrintWriter out = response.getWriter();
out.println("THE_STRING_TO_SEND_AS_RESPONSE");
return null;
This woks for me.
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<byte[]> 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<byte[]>(uploadedBytes, headers, HttpStatus.OK);
}
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...);
@ResponseBody
@RequestMapping(value="/get-text", produces="text/plain")
public String myMethod() {
return "Response!";
}
@ResponseBody
?It's telling that the method returns some text and not to interpret it as a view etc.
produces="text/plain"
?It's just a good practice as it tells what will be returned from the method :)
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
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("/create")
public String foo()
{
String result = "something"
return "\"" + result + "\"";
}
Source: Stackoverflow.com