Fix UriComponentsBuilder examples in ref docs

Closes gh-26453

spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,6 +51,27 @@ import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException
  */
 class UriComponentsBuilderTests {
 
+	@Test  // see gh-26453
+	void examplesInReferenceManual() {
+		final String expected = "/hotel%20list/New%20York?q=foo%2Bbar";
+
+		URI uri = UriComponentsBuilder.fromPath("/hotel list/{city}")
+			.queryParam("q", "{q}")
+			.encode()
+			.buildAndExpand("New York", "foo+bar")
+			.toUri();
+		assertThat(uri).asString().isEqualTo(expected);
+
+		uri = UriComponentsBuilder.fromPath("/hotel list/{city}")
+			.queryParam("q", "{q}")
+			.build("New York", "foo+bar");
+		assertThat(uri).asString().isEqualTo(expected);
+
+		uri = UriComponentsBuilder.fromUriString("/hotel list/{city}?q={q}")
+			.build("New York", "foo+bar");
+		assertThat(uri).asString().isEqualTo(expected);
+	}
+
 	@Test
 	void plain() throws URISyntaxException {
 		UriComponentsBuilder builder = UriComponentsBuilder.newInstance();