Minor refactoring in DefaultServerRequest

Ensure bind logic is shared across DefaultServerRequest and
BuiltServerRequest.

See gh-35800

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerRequest.java

@@ -246,8 +246,15 @@ class DefaultServerRequest implements ServerRequest {
 	}
 
 	@Override
-	@SuppressWarnings("unchecked")
 	public <T> T bind(Class<T> bindType, Consumer<WebDataBinder> dataBinderCustomizer) throws BindException {
+		return doBind(bindType, dataBinderCustomizer, servletRequest());
+	}
+
+	@SuppressWarnings("unchecked")
+	static <T> T doBind(
+			Class<T> bindType, Consumer<WebDataBinder> dataBinderCustomizer, HttpServletRequest servletRequest)
+			throws BindException {
+
 		Assert.notNull(bindType, "BindType must not be null");
 		Assert.notNull(dataBinderCustomizer, "DataBinderCustomizer must not be null");
 
@@ -255,7 +262,6 @@ class DefaultServerRequest implements ServerRequest {
 		dataBinder.setTargetType(ResolvableType.forClass(bindType));
 		dataBinderCustomizer.accept(dataBinder);
 
-		HttpServletRequest servletRequest = servletRequest();
 		dataBinder.construct(servletRequest);
 		dataBinder.bind(servletRequest);
 

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerRequestBuilder.java

@@ -55,10 +55,8 @@ import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.validation.BindException;
-import org.springframework.validation.BindingResult;
 import org.springframework.web.HttpMediaTypeNotSupportedException;
 import org.springframework.web.accept.ApiVersionStrategy;
-import org.springframework.web.bind.ServletRequestDataBinder;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.util.UriBuilder;
 import org.springframework.web.util.UriComponentsBuilder;
@@ -343,32 +341,8 @@ class DefaultServerRequestBuilder implements ServerRequest.Builder {
 		}
 
 		@Override
-		@SuppressWarnings("unchecked")
 		public <T> T bind(Class<T> bindType, Consumer<WebDataBinder> dataBinderCustomizer) throws BindException {
-			Assert.notNull(bindType, "BindType must not be null");
-			Assert.notNull(dataBinderCustomizer, "DataBinderCustomizer must not be null");
-
-			ServletRequestDataBinder dataBinder = new ServletRequestDataBinder(null);
-			dataBinder.setTargetType(ResolvableType.forClass(bindType));
-			dataBinderCustomizer.accept(dataBinder);
-
-			HttpServletRequest servletRequest = servletRequest();
-			dataBinder.construct(servletRequest);
-			dataBinder.bind(servletRequest);
-
-			BindingResult bindingResult = dataBinder.getBindingResult();
-			if (bindingResult.hasErrors()) {
-				throw new BindException(bindingResult);
-			}
-			else {
-				T result = (T) bindingResult.getTarget();
-				if (result != null) {
-					return result;
-				}
-				else {
-					throw new IllegalStateException("Binding result has neither target nor errors");
-				}
-			}
+			return DefaultServerRequest.doBind(bindType, dataBinderCustomizer, servletRequest());
 		}
 
 		@Override