Polish ContentCachingResponseWrapper[Tests]

spring-web/src/main/java/org/springframework/web/util/ContentCachingResponseWrapper.java

@@ -38,7 +38,7 @@ import org.springframework.util.FastByteArrayOutputStream;
 /**
  * {@link javax.servlet.http.HttpServletResponse} wrapper that caches all content written to
  * the {@linkplain #getOutputStream() output stream} and {@linkplain #getWriter() writer},
- * and allows this content to be retrieved via a {@link #getContentAsByteArray() byte array}.
+ * and allows this content to be retrieved via a {@linkplain #getContentAsByteArray() byte array}.
  *
  * <p>Used e.g. by {@link org.springframework.web.filter.ShallowEtagHeaderFilter}.
  * Note: As of Spring Framework 5.0, this wrapper is built on the Servlet 3.1 API.
@@ -122,9 +122,16 @@ public class ContentCachingResponseWrapper extends HttpServletResponseWrapper {
 		return this.writer;
 	}
 
+	/**
+	 * This method neither flushes content to the client nor commits the underlying
+	 * response, since the content has not yet been copied to the response.
+	 * <p>Invoke {@link #copyBodyToResponse()} to copy the cached body content to
+	 * the wrapped response object and flush its buffer.
+	 * @see javax.servlet.ServletResponseWrapper#flushBuffer()
+	 */
 	@Override
 	public void flushBuffer() throws IOException {
-		// do not flush the underlying response as the content has not been copied to it yet
+		// no-op
 	}
 
 	@Override
@@ -142,15 +149,11 @@ public class ContentCachingResponseWrapper extends HttpServletResponseWrapper {
 			throw new IllegalArgumentException("Content-Length exceeds ContentCachingResponseWrapper's maximum (" +
 					Integer.MAX_VALUE + "): " + len);
 		}
-		int lenInt = (int) len;
-		if (lenInt > this.content.size()) {
-			this.content.resize(lenInt);
-		}
-		this.contentLength = lenInt;
+		setContentLength((int) len);
 	}
 
 	@Override
-	public void setContentType(String type) {
+	public void setContentType(@Nullable String type) {
 		this.contentType = type;
 	}
 

spring-web/src/test/java/org/springframework/web/filter/ContentCachingResponseWrapperTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,55 +16,69 @@
 
 package org.springframework.web.filter;
 
-import java.nio.charset.StandardCharsets;
-
 import javax.servlet.http.HttpServletResponse;
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.http.HttpHeaders;
 import org.springframework.util.FileCopyUtils;
 import org.springframework.web.testfixture.servlet.MockHttpServletResponse;
 import org.springframework.web.util.ContentCachingResponseWrapper;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.http.HttpHeaders.CONTENT_LENGTH;
+import static org.springframework.http.HttpHeaders.TRANSFER_ENCODING;
 
 /**
  * Unit tests for {@link ContentCachingResponseWrapper}.
+ *
  * @author Rossen Stoyanchev
  */
 public class ContentCachingResponseWrapperTests {
 
 	@Test
 	void copyBodyToResponse() throws Exception {
-		byte[] responseBody = "Hello World".getBytes(StandardCharsets.UTF_8);
+		byte[] responseBody = "Hello World".getBytes(UTF_8);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
 		ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper(response);
-		responseWrapper.setStatus(HttpServletResponse.SC_OK);
+		responseWrapper.setStatus(HttpServletResponse.SC_CREATED);
 		FileCopyUtils.copy(responseBody, responseWrapper.getOutputStream());
 		responseWrapper.copyBodyToResponse();
 
-		assertThat(response.getStatus()).isEqualTo(200);
-		assertThat(response.getContentLength() > 0).isTrue();
+		assertThat(response.getStatus()).isEqualTo(HttpServletResponse.SC_CREATED);
+		assertThat(response.getContentLength()).isGreaterThan(0);
 		assertThat(response.getContentAsByteArray()).isEqualTo(responseBody);
 	}
 
 	@Test
 	void copyBodyToResponseWithTransferEncoding() throws Exception {
-		byte[] responseBody = "6\r\nHello 5\r\nWorld0\r\n\r\n".getBytes(StandardCharsets.UTF_8);
+		byte[] responseBody = "6\r\nHello 5\r\nWorld0\r\n\r\n".getBytes(UTF_8);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
 		ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper(response);
-		responseWrapper.setStatus(HttpServletResponse.SC_OK);
-		responseWrapper.setHeader(HttpHeaders.TRANSFER_ENCODING, "chunked");
+		responseWrapper.setStatus(HttpServletResponse.SC_CREATED);
+		responseWrapper.setHeader(TRANSFER_ENCODING, "chunked");
 		FileCopyUtils.copy(responseBody, responseWrapper.getOutputStream());
 		responseWrapper.copyBodyToResponse();
 
-		assertThat(response.getStatus()).isEqualTo(200);
-		assertThat(response.getHeader(HttpHeaders.TRANSFER_ENCODING)).isEqualTo("chunked");
-		assertThat(response.getHeader(HttpHeaders.CONTENT_LENGTH)).isNull();
+		assertThat(response.getStatus()).isEqualTo(HttpServletResponse.SC_CREATED);
+		assertHeader(response, TRANSFER_ENCODING, "chunked");
+		assertHeader(response, CONTENT_LENGTH, null);
 		assertThat(response.getContentAsByteArray()).isEqualTo(responseBody);
 	}
 
+	private void assertHeader(HttpServletResponse response, String header, String value) {
+		if (value == null) {
+			assertThat(response.containsHeader(header)).as(header).isFalse();
+			assertThat(response.getHeader(header)).as(header).isNull();
+			assertThat(response.getHeaders(header)).as(header).isEmpty();
+		}
+		else {
+			assertThat(response.containsHeader(header)).as(header).isTrue();
+			assertThat(response.getHeader(header)).as(header).isEqualTo(value);
+			assertThat(response.getHeaders(header)).as(header).containsExactly(value);
+		}
+	}
+
 }