‘+’ (plus sign) not encoded with RestTemplate using String url, but interpreted as ‘ ‘ (space)

We realized the URL can be modified in an interceptor after the encoding is done. So a solution would be to use an interceptor, that encodes the plus sign in the query params.

RestTemplate restTemplate = new RestTemplateBuilder()
        .rootUri("http://localhost:8080")
        .interceptors(new PlusEncoderInterceptor())
        .build();

A shortened example:

public class PlusEncoderInterceptor implements ClientHttpRequestInterceptor {

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        return execution.execute(new HttpRequestWrapper(request) {
            @Override
            public URI getURI() {
                URI u = super.getURI();
                String strictlyEscapedQuery = StringUtils.replace(u.getRawQuery(), "+", "%2B");
                return UriComponentsBuilder.fromUri(u)
                        .replaceQuery(strictlyEscapedQuery)
                        .build(true).toUri();
            }
        }, body);
    }
}