SPR-8803 Refine UriComponentsBuilder.replaceQueryParam().

If no values are given, the query parameter is removed.

org.springframework.web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java

@@ -404,7 +404,7 @@ public class UriComponentsBuilder {
 
 	/**
 	 * Sets the query parameter values overriding all existing query values for the same parameter.
-	 * If no values are given, the resulting URI will contain the query parameter name only.
+	 * If no values are given, the query parameter is removed.
 	 * 
 	 * @param name   the query parameter name
 	 * @param values the query parameter values
@@ -413,7 +413,9 @@ public class UriComponentsBuilder {
 	public UriComponentsBuilder replaceQueryParam(String name, Object... values) {
 		Assert.notNull(name, "'name' must not be null");
 		this.queryParams.remove(name);
-		queryParam(name, values);
+		if (!ObjectUtils.isEmpty(values)) {
+			queryParam(name, values);
+		}
 		return this;
 	}
     

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

@@ -240,7 +240,7 @@ public class UriComponentsBuilderTests {
 		builder.replaceQueryParam("baz");
 		result = builder.build();
 		
-		assertEquals("baz", result.getQuery());
+		assertNull("Query param should have been deleted", result.getQuery());
 	}
 
 }

spring-framework-reference/src/mvc.xml

@@ -2905,11 +2905,14 @@ URI uri = uriComponents.expand("42", "21").encode().toUri();
 	<para>In a Servlet environment the 
 	<classname>ServletUriComponentsBuilder</classname> sub-class provides
 	static factory methods to copy available URL information from a 
-	Servlet request including host, scheme, port, path and query string: 
+	Servlet requests: 
 	</para>
 
 <programlisting language="java">HttpServletRequest request = ...
 
+// Re-use host, scheme, port, path and query string
+// Replace the "accountId" query param
+
 ServletUriComponentsBuilder ucb = 
         ServletUriComponentsBuilder.fromRequest(request).replaceQueryParam("accountId", "{id}").build()
             .expand("123")
@@ -2919,7 +2922,9 @@ ServletUriComponentsBuilder ucb =
     <para>Alternatively, you may choose to copy a subset of the available 
     information up to and including the context path:</para>
 
-<programlisting language="java">// Host, port and context path
+<programlisting language="java">// Re-use host, port and context path
+// Append "/accounts" to the path
+
 ServletUriComponentsBuilder ucb = 
         ServletUriComponentsBuilder.fromContextPath(request).path("/accounts").build()
 </programlisting>
@@ -2928,7 +2933,10 @@ ServletUriComponentsBuilder ucb =
     by name (e.g. <literal>/main/*</literal>), you can also have the literal part 
     of the servlet mapping included:</para>
 
-<programlisting language="java">// Host, port, context path, and the literal part of the servlet mapping
+<programlisting language="java">// Re-use host, port, context path
+// Append the literal part of the servlet mapping to the path
+// Append "/accounts" to the path
+
 ServletUriComponentsBuilder ucb = 
         ServletUriComponentsBuilder.fromServletMapping(request).path("/accounts").build()
 </programlisting>