URLDecoder: Illegal hex characters in escape (%) pattern for multipart data

Question

I am using multipart to fetch the pdf and object data from the service. I get the below error

java.lang.IllegalArgumentException: URLDecoder: Illegal hex characters in escape (%) pattern - For input string: "PD" at java.net.URLDecoder.decode(URLDecoder.java:205) at org.springframework.http.converter.FormHttpMessageConverter.read(FormHttpMessageConverter.java:186)

when invoking the service.

SERVICE :


@RequestMapping(value = "/getPDF", method = RequestMethod.GET,produces = MediaType.MULTIPART_FORM_DATA_VALUE)
 public ResponseEntity<MultiValueMap<String, Object>> getPDF(
   @RequestParam String key,
   HttpServletResponse response)  {
  

 
  MultiValueMap<String, Object> pdfResultMap = new LinkedMultiValueMap<String, Object>();
  
  
  //Get the result 
  ByteArrayResource byteArrayResource = getPdf(); //Assign the PDF
  
  
  //1) Build the first byte[] result
/*     LinkedMultiValueMap<String, String> pdfMap = new LinkedMultiValueMap<>();
     pdfMap.add("Content-disposition", "attachment;" );
     pdfMap.add("Content-type", "application/pdf");*/
    HttpHeaders xHeader2 = new HttpHeaders();
      xHeader2.setContentType(MediaType.APPLICATION_PDF);
     HttpEntity<ByteArrayResource> doc = new HttpEntity<ByteArrayResource>(byteArrayResource, xHeader2);
     pdfResultMap.add("doc", doc);
     
        // 2) Build the next 
     //Header
     HttpHeaders xHeader = new HttpHeaders();
     xHeader.setContentType(MediaType.APPLICATION_JSON);
     
    // Get the result
     Map<String, String> stringMap = new HashMap<String, String>();
    //populate String map
     
     HttpEntity<Map<String, String>> stringMapObject = new HttpEntity<Map<String, String>>(stringMap, xHeader);
     pdfResultMap.add("stringMap", stringMapObject);
     
     //3) Build the simple header 
     
     HttpHeaders xHeader1 = new HttpHeaders();
     xHeader.setContentType(MediaType.APPLICATION_JSON);
     HttpEntity<String> titlePart = new HttpEntity<String>("pdftitle", xHeader1);
     pdfResultMap.add("title", titlePart);
     
  ResponseEntity<MultiValueMap<String, Object>> responseEntity = new ResponseEntity<MultiValueMap<String, Object>>(pdfResultMap, HttpStatus.OK);

  return responseEntity;
 }
 
 
 CLIENT :
 
 public getPdf() {
 
 FormHttpMessageConverter formConverter = new FormHttpMessageConverter() {
      @Override
      public boolean canRead(Class<?> clazz, MediaType mediaType) {
          if (clazz == MultiValueMap.class) {
              return true;
          }
          return super.canRead(clazz, mediaType);
      }
  };
  
  
  formConverter.setCharset(Charset.forName("UTF-8"));
     List<HttpMessageConverter<?>> partConverters = new ArrayList<HttpMessageConverter<?>>();
     partConverters.add(new ByteArrayHttpMessageConverter());
     StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
     stringHttpMessageConverter.setWriteAcceptCharset(false);
     partConverters.add(stringHttpMessageConverter);
     partConverters.add(new ResourceHttpMessageConverter());   
     formConverter.setPartConverters(partConverters);
 
 
    restTemplate.getMessageConverters().add(formConverter); 
    
    ResponseEntity<MultiValueMap> response =  restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.GET,entity, MultiValueMap.class);
    
    
    }
    
    
I  Tried adding :
        

         List<MediaType> a = new ArrayList<MediaType>();
      a.add(MediaType.APPLICATION_OCTET_STREAM);
      a.add(MediaType.MULTIPART_FORM_DATA);
      a.add(new MediaType("application","pdf"));
    formConverter.setSupportedMediaTypes(a);  

But the same error .

Anything I am missing here?

Answer 1

You try to read from FormHttpMessageConverter but the doc https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/http/converter/FormHttpMessageConverter.html says

"In other words, this converter can read and write the "application/x-www-form-urlencoded" media type as MultiValueMap and it can also write (but not read) the "multipart/form-data" media type as MultiValueMap."