Refactor eTag formatting into utility method

See gh-33412

Author: hyunmin0317

spring-web/src/main/java/org/springframework/http/ETag.java

@@ -134,6 +134,15 @@ public static List<ETag> parse(String source) {
 		return result;
 	}
 
+	public static String format(String etag) {
+		if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
+			etag = "\"" + etag;
+		}
+		if (!etag.endsWith("\"")) {
+			etag = etag + "\"";
+		}
+		return etag;
+	}
 
 	private enum State {
 

spring-web/src/main/java/org/springframework/http/ResponseEntity.java

@@ -570,12 +570,7 @@ public BodyBuilder contentType(MediaType contentType) {
 		@Override
 		public BodyBuilder eTag(@Nullable String etag) {
 			if (etag != null) {
-				if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
-					etag = "\"" + etag;
-				}
-				if (!etag.endsWith("\"")) {
-					etag = etag + "\"";
-				}
+				etag = ETag.format(etag);
 			}
 			this.headers.setETag(etag);
 			return this;

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultEntityResponseBuilder.java

@@ -28,16 +28,10 @@
 import java.util.Set;
 import java.util.function.Consumer;
 
+import org.springframework.http.*;
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.codec.Hints;
-import org.springframework.http.CacheControl;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.HttpStatusCode;
-import org.springframework.http.MediaType;
-import org.springframework.http.ResponseCookie;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
@@ -148,12 +142,7 @@ public EntityResponse.Builder<T> contentType(MediaType contentType) {
 
 	@Override
 	public EntityResponse.Builder<T> eTag(String etag) {
-		if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
-			etag = "\"" + etag;
-		}
-		if (!etag.endsWith("\"")) {
-			etag = etag + "\"";
-		}
+		etag = ETag.format(etag);
 		this.headers.setETag(etag);
 		return this;
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultServerResponseBuilder.java

@@ -32,17 +32,11 @@
 import java.util.function.Function;
 
 import org.reactivestreams.Publisher;
+import org.springframework.http.*;
 import reactor.core.publisher.Mono;
 
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.codec.Hints;
-import org.springframework.http.CacheControl;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpStatusCode;
-import org.springframework.http.MediaType;
-import org.springframework.http.ReactiveHttpOutputMessage;
-import org.springframework.http.ResponseCookie;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
@@ -148,12 +142,7 @@ public ServerResponse.BodyBuilder contentType(MediaType contentType) {
 	@Override
 	public ServerResponse.BodyBuilder eTag(String etag) {
 		Assert.notNull(etag, "etag must not be null");
-		if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
-			etag = "\"" + etag;
-		}
-		if (!etag.endsWith("\"")) {
-			etag = etag + "\"";
-		}
+		etag = ETag.format(etag);
 		this.headers.setETag(etag);
 		return this;
 	}

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

@@ -45,14 +45,7 @@
 import org.springframework.core.io.InputStreamResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.ResourceRegion;
-import org.springframework.http.CacheControl;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpRange;
-import org.springframework.http.HttpStatus;
-import org.springframework.http.HttpStatusCode;
-import org.springframework.http.InvalidMediaTypeException;
-import org.springframework.http.MediaType;
+import org.springframework.http.*;
 import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.SmartHttpMessageConverter;
@@ -166,12 +159,7 @@ public EntityResponse.Builder<T> contentType(MediaType contentType) {
 
 	@Override
 	public EntityResponse.Builder<T> eTag(String etag) {
-		if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
-			etag = "\"" + etag;
-		}
-		if (!etag.endsWith("\"")) {
-			etag = etag + "\"";
-		}
+		etag = ETag.format(etag);
 		this.headers.setETag(etag);
 		return this;
 	}

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

@@ -30,11 +30,7 @@
 import jakarta.servlet.http.HttpServletResponse;
 
 import org.springframework.core.ParameterizedTypeReference;
-import org.springframework.http.CacheControl;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.HttpStatusCode;
-import org.springframework.http.MediaType;
+import org.springframework.http.*;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.LinkedMultiValueMap;
@@ -128,12 +124,7 @@ public ServerResponse.BodyBuilder contentType(MediaType contentType) {
 	@Override
 	public ServerResponse.BodyBuilder eTag(String etag) {
 		Assert.notNull(etag, "etag must not be null");
-		if (!etag.startsWith("\"") && !etag.startsWith("W/\"")) {
-			etag = "\"" + etag;
-		}
-		if (!etag.endsWith("\"")) {
-			etag = etag + "\"";
-		}
+		etag = ETag.format(etag);
 		this.headers.setETag(etag);
 		return this;
 	}