Lenient port handling in HierarchicalUriComponents#toUriString

Closes gh-32003

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/util/HierarchicalUriComponents.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -485,7 +485,7 @@ public String toUriString() {
 			if (this.host != null) {
 				uriBuilder.append(this.host);
 			}
-			if (getPort() != -1) {
+			if (StringUtils.hasText(this.port) && !this.port.equals("-1")) {
 				uriBuilder.append(':').append(this.port);
 			}
 		}

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

@@ -101,6 +101,12 @@ void toUriWithIpv6HostAlreadyEncoded() {
 				URI.create("http://[1abc:2abc:3abc::5ABC:6abc]:8080/hotel%20list/Z%C3%BCrich"));
 	}
 
+	@Test
+	void toUriStringWithPortVariable() {
+		String url = "http://localhost:{port}/first";
+		assertThat(UriComponentsBuilder.fromUriString(url).build().toUriString()).isEqualTo(url);
+	}
+
 	@Test
 	void expand() {
 		UriComponents uri = UriComponentsBuilder.fromUriString("https://example.com").path("/{foo} {bar}").build();
@@ -166,12 +172,6 @@ private void assertExceptionsForInvalidPort(UriComponents uriComponents) {
 		assertThatIllegalStateException()
 			.isThrownBy(uriComponents::toUri)
 			.withMessage("The port must be an integer: XXX");
-		assertThatIllegalStateException()
-			.isThrownBy(uriComponents::toUriString)
-			.withMessage("The port must be an integer: XXX");
-		assertThatIllegalStateException()
-			.isThrownBy(uriComponents::toString)
-			.withMessage("The port must be an integer: XXX");
 	}
 
 	@Test