Include FormHttpMessageReader in client codecs

Issue: SPR-16804

spring-web/src/main/java/org/springframework/http/codec/support/DefaultClientCodecConfigurer.java

@@ -24,6 +24,7 @@ import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
 import org.springframework.http.codec.ClientCodecConfigurer;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
+import org.springframework.http.codec.FormHttpMessageReader;
 import org.springframework.http.codec.FormHttpMessageWriter;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.HttpMessageWriter;
@@ -70,6 +71,16 @@ public class DefaultClientCodecConfigurer extends AbstractCodecConfigurer implem
 			this.sseDecoder = decoder;
 		}
 
+		@Override
+		List<HttpMessageReader<?>> getTypedReaders() {
+			if (!shouldRegisterDefaults()) {
+				return Collections.emptyList();
+			}
+			List<HttpMessageReader<?>> result = super.getTypedReaders();
+			result.add(new FormHttpMessageReader());
+			return result;
+		}
+
 		@Override
 		List<HttpMessageReader<?>> getObjectReaders() {
 			if (!shouldRegisterDefaults()) {

spring-web/src/test/java/org/springframework/http/codec/support/ClientCodecConfigurerTests.java

@@ -43,6 +43,7 @@ import org.springframework.http.MediaType;
 import org.springframework.http.codec.ClientCodecConfigurer;
 import org.springframework.http.codec.DecoderHttpMessageReader;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
+import org.springframework.http.codec.FormHttpMessageReader;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.codec.ResourceHttpMessageWriter;
@@ -74,12 +75,13 @@ public class ClientCodecConfigurerTests {
 	@Test
 	public void defaultReaders() {
 		List<HttpMessageReader<?>> readers = this.configurer.getReaders();
-		assertEquals(10, readers.size());
+		assertEquals(11, readers.size());
 		assertEquals(ByteArrayDecoder.class, getNextDecoder(readers).getClass());
 		assertEquals(ByteBufferDecoder.class, getNextDecoder(readers).getClass());
 		assertEquals(DataBufferDecoder.class, getNextDecoder(readers).getClass());
 		assertEquals(ResourceDecoder.class, getNextDecoder(readers).getClass());
 		assertStringDecoder(getNextDecoder(readers), true);
+		assertEquals(FormHttpMessageReader.class, readers.get(this.index.getAndIncrement()).getClass()); // SPR-16804
 		assertEquals(Jackson2JsonDecoder.class, getNextDecoder(readers).getClass());
 		assertEquals(Jackson2SmileDecoder.class, getNextDecoder(readers).getClass());
 		assertEquals(Jaxb2XmlDecoder.class, getNextDecoder(readers).getClass());