Support declarativeBinding mode in DataBinder

Closes gh-30948

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -153,6 +153,8 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	@Nullable
 	private ExtendedTypeConverter typeConverter;
 
+	private boolean declarativeBinding = false;
+
 	private boolean ignoreUnknownFields = true;
 
 	private boolean ignoreInvalidFields = false;
@@ -425,6 +427,28 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 		return getInternalBindingResult();
 	}
 
+	/**
+	 * Set whether to bind only fields explicitly intended for binding including:
+	 * <ul>
+	 * <li>Constructor binding via {@link #construct}.
+	 * <li>Property binding with configured
+	 * {@link #setAllowedFields(String...) allowedFields}.
+	 * </ul>
+	 * <p>Default is "false". Turn this on to limit binding to constructor
+	 * parameters and allowed fields.
+	 * @since 6.1
+	 */
+	public void setDeclarativeBinding(boolean declarativeBinding) {
+		this.declarativeBinding = declarativeBinding;
+	}
+
+	/**
+	 * Return whether to bind only fields intended for binding.
+	 * @since 6.1
+	 */
+	public boolean isDeclarativeBinding() {
+		return this.declarativeBinding;
+	}
 
 	/**
 	 * Set whether to ignore unknown fields, that is, whether to ignore bind
@@ -1031,11 +1055,24 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * @see #doBind(org.springframework.beans.MutablePropertyValues)
 	 */
 	public void bind(PropertyValues pvs) {
+		if (shouldNotBindPropertyValues()) {
+			return;
+		}
 		MutablePropertyValues mpvs = (pvs instanceof MutablePropertyValues mutablePropertyValues ?
 				mutablePropertyValues : new MutablePropertyValues(pvs));
 		doBind(mpvs);
 	}
 
+	/**
+	 * Whether to not bind parameters to properties. Returns "true" if
+	 * {@link #isDeclarativeBinding()} is on, and
+	 * {@link #setAllowedFields(String...) allowedFields} are not configured.
+	 * @since 6.1
+	 */
+	protected boolean shouldNotBindPropertyValues() {
+		return (isDeclarativeBinding() && ObjectUtils.isEmpty(this.allowedFields));
+	}
+
 	/**
 	 * Actual implementation of the binding process, working with the
 	 * passed-in MutablePropertyValues instance.

spring-context/src/test/java/org/springframework/validation/DataBinderTests.java

@@ -681,6 +681,23 @@ class DataBinderTests {
 		assertThat(dataBinder.convertIfNecessary(bean, String.class)).as("Type converter should have been used").isEqualTo("[Fred]");
 	}
 
+	@Test
+	void bindingInDeclarativeMode() throws BindException {
+		TestBean rod = new TestBean();
+		DataBinder binder = new DataBinder(rod);
+		binder.setDeclarativeBinding(true);
+
+		MutablePropertyValues pvs = new MutablePropertyValues();
+		pvs.add("name", "Rod");
+		pvs.add("age", "32x");
+
+		binder.bind(pvs);
+		binder.close();
+
+		assertThat(rod.getName()).isNull();
+		assertThat(rod.getAge()).isEqualTo(0);
+	}
+
 	@Test
 	void bindingWithAllowedFields() throws BindException {
 		TestBean rod = new TestBean();

spring-web/src/main/java/org/springframework/web/bind/ServletRequestDataBinder.java

@@ -140,6 +140,9 @@ public class ServletRequestDataBinder extends WebDataBinder {
 	 * @see #bind(org.springframework.beans.PropertyValues)
 	 */
 	public void bind(ServletRequest request) {
+		if (shouldNotBindPropertyValues()) {
+			return;
+		}
 		MutablePropertyValues mpvs = new ServletRequestParameterPropertyValues(request);
 		MultipartRequest multipartRequest = WebUtils.getNativeRequest(request, MultipartRequest.class);
 		if (multipartRequest != null) {

spring-web/src/main/java/org/springframework/web/bind/support/ConfigurableWebBindingInitializer.java

@@ -44,6 +44,9 @@ public class ConfigurableWebBindingInitializer implements WebBindingInitializer
 
 	private boolean directFieldAccess = false;
 
+	@Nullable
+	private Boolean declarativeBinding;
+
 	@Nullable
 	private MessageCodesResolver messageCodesResolver;
 
@@ -99,6 +102,23 @@ public class ConfigurableWebBindingInitializer implements WebBindingInitializer
 		return this.directFieldAccess;
 	}
 
+	/**
+	 * Set whether to bind only fields intended for binding as described in
+	 * {@link org.springframework.validation.DataBinder#setDeclarativeBinding}.
+	 * @since 6.1
+	 */
+	public void setDeclarativeBinding(boolean declarativeBinding) {
+		this.declarativeBinding = declarativeBinding;
+	}
+
+	/**
+	 * Return whether to bind only fields intended for binding.
+	 * @since 6.1
+	 */
+	public boolean isDeclarativeBinding() {
+		return (this.declarativeBinding != null ? this.declarativeBinding : false);
+	}
+
 	/**
 	 * Set the strategy to use for resolving errors into message codes.
 	 * Applies the given strategy to all data binders used by this controller.
@@ -197,6 +217,9 @@ public class ConfigurableWebBindingInitializer implements WebBindingInitializer
 		if (this.directFieldAccess) {
 			binder.initDirectFieldAccess();
 		}
+		if (this.declarativeBinding != null) {
+			binder.setDeclarativeBinding(this.declarativeBinding);
+		}
 		if (this.messageCodesResolver != null) {
 			binder.setMessageCodesResolver(this.messageCodesResolver);
 		}

spring-web/src/main/java/org/springframework/web/bind/support/WebExchangeDataBinder.java

@@ -93,6 +93,9 @@ public class WebExchangeDataBinder extends WebDataBinder {
 	 * @return a {@code Mono<Void>} that completes when binding is complete
 	 */
 	public Mono<Void> bind(ServerWebExchange exchange) {
+		if (shouldNotBindPropertyValues()) {
+			return Mono.empty();
+		}
 		return getValuesToBind(exchange)
 				.doOnNext(map -> doBind(new MutablePropertyValues(map)))
 				.then();

spring-web/src/main/java/org/springframework/web/bind/support/WebRequestDataBinder.java

@@ -138,6 +138,9 @@ public class WebRequestDataBinder extends WebDataBinder {
 	 * @see #bind(org.springframework.beans.PropertyValues)
 	 */
 	public void bind(WebRequest request) {
+		if (shouldNotBindPropertyValues()) {
+			return;
+		}
 		MutablePropertyValues mpvs = new MutablePropertyValues(request.getParameterMap());
 		if (request instanceof NativeWebRequest nativeRequest) {
 			MultipartRequest multipartRequest = nativeRequest.getNativeRequest(MultipartRequest.class);

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ServletAnnotationControllerHandlerMethodTests.java

@@ -2056,6 +2056,26 @@ class ServletAnnotationControllerHandlerMethodTests extends AbstractServletHandl
 		assertThat(response.getContentAsString()).isEqualTo("value1-true-3");
 	}
 
+	@PathPatternsParameterizedTest
+	void dataClassBindingWithAdditionalSetterInDeclarativeBindingMode(boolean usePathPatterns) throws Exception {
+		initDispatcherServlet(DataClassController.class, usePathPatterns, wac -> {
+			ConfigurableWebBindingInitializer initializer = new ConfigurableWebBindingInitializer();
+			initializer.setDeclarativeBinding(true);
+
+			RootBeanDefinition mappingDef = new RootBeanDefinition(RequestMappingHandlerAdapter.class);
+			mappingDef.getPropertyValues().add("webBindingInitializer", initializer);
+			wac.registerBeanDefinition("handlerAdapter", mappingDef);
+		});
+
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", "/bind");
+		request.addParameter("param1", "value1");
+		request.addParameter("param2", "true");
+		request.addParameter("param3", "3");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		getServlet().service(request, response);
+		assertThat(response.getContentAsString()).isEqualTo("value1-true-0");
+	}
+
 	@PathPatternsParameterizedTest
 	void dataClassBindingWithResult(boolean usePathPatterns) throws Exception {
 		initDispatcherServlet(ValidatedDataClassController.class, usePathPatterns);