CharacterEncodingFilter provides convenience constructors for Servlet 3.0 style usage

Issue: SPR-13572

Author: jhoeller

spring-web/src/main/java/org/springframework/web/filter/CharacterEncodingFilter.java

@@ -22,6 +22,8 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.util.Assert;
+
 /**
  * Servlet Filter that allows one to specify a character encoding for requests.
  * This is useful because current browsers typically do not set a character
@@ -47,6 +49,40 @@ public class CharacterEncodingFilter extends OncePerRequestFilter {
 	private boolean forceEncoding = false;
 
 
+	/**
+	 * Create a default {@code CharacterEncodingFilter},
+	 * with the encoding to be set via {@link #setEncoding}.
+	 * @see #setEncoding
+	 */
+	public CharacterEncodingFilter() {
+	}
+
+	/**
+	 * Create a {@code CharacterEncodingFilter} for the given encoding.
+	 * @param encoding the encoding to apply
+	 * @since 4.2.3
+	 * @see #setEncoding
+	 */
+	public CharacterEncodingFilter(String encoding) {
+		this(encoding, false);
+	}
+
+	/**
+	 * Create a {@code CharacterEncodingFilter} for the given encoding.
+	 * @param encoding the encoding to apply
+	 * @param forceEncoding whether the specified encoding is supposed to
+	 * override existing request and response encodings
+	 * @since 4.2.3
+	 * @see #setEncoding
+	 * @see #setForceEncoding
+	 */
+	public CharacterEncodingFilter(String encoding, boolean forceEncoding) {
+		Assert.hasLength(encoding, "Encoding must not be empty");
+		this.encoding = encoding;
+		this.forceEncoding = forceEncoding;
+	}
+
+
 	/**
 	 * Set the encoding to use for requests. This encoding will be passed into a
 	 * {@link javax.servlet.http.HttpServletRequest#setCharacterEncoding} call.

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

@@ -32,6 +32,7 @@
 /**
  * @author Rick Evans
  * @author Juergen Hoeller
+ * @author Vedran Pavic
  */
 public class CharacterEncodingFilterTests {
 
@@ -50,9 +51,7 @@ public void forceEncodingAlwaysSetsEncoding() throws Exception {
 		HttpServletResponse response = mock(HttpServletResponse.class);
 		FilterChain filterChain = mock(FilterChain.class);
 
-		CharacterEncodingFilter filter = new CharacterEncodingFilter();
-		filter.setForceEncoding(true);
-		filter.setEncoding(ENCODING);
+		CharacterEncodingFilter filter = new CharacterEncodingFilter(ENCODING, true);
 		filter.init(new MockFilterConfig(FILTER_NAME));
 		filter.doFilter(request, response, filterChain);
 
@@ -73,9 +72,7 @@ public void encodingIfEmptyAndNotForced() throws Exception {
 
 		FilterChain filterChain = mock(FilterChain.class);
 
-		CharacterEncodingFilter filter = new CharacterEncodingFilter();
-		filter.setForceEncoding(false);
-		filter.setEncoding(ENCODING);
+		CharacterEncodingFilter filter = new CharacterEncodingFilter(ENCODING);
 		filter.init(new MockFilterConfig(FILTER_NAME));
 		filter.doFilter(request, response, filterChain);
 
@@ -86,7 +83,7 @@ public void encodingIfEmptyAndNotForced() throws Exception {
 	}
 
 	@Test
-	public void doesNowtIfEncodingIsNotEmptyAndNotForced() throws Exception {
+	public void doesNotIfEncodingIsNotEmptyAndNotForced() throws Exception {
 		HttpServletRequest request = mock(HttpServletRequest.class);
 		given(request.getCharacterEncoding()).willReturn(ENCODING);
 		given(request.getAttribute(WebUtils.ERROR_REQUEST_URI_ATTRIBUTE)).willReturn(null);
@@ -96,8 +93,7 @@ public void doesNowtIfEncodingIsNotEmptyAndNotForced() throws Exception {
 
 		FilterChain filterChain = mock(FilterChain.class);
 
-		CharacterEncodingFilter filter = new CharacterEncodingFilter();
-		filter.setEncoding(ENCODING);
+		CharacterEncodingFilter filter = new CharacterEncodingFilter(ENCODING);
 		filter.init(new MockFilterConfig(FILTER_NAME));
 		filter.doFilter(request, response, filterChain);
 
@@ -140,8 +136,7 @@ public void withIncompleteInitialization() throws Exception {
 
 		FilterChain filterChain = mock(FilterChain.class);
 
-		CharacterEncodingFilter filter = new CharacterEncodingFilter();
-		filter.setEncoding(ENCODING);
+		CharacterEncodingFilter filter = new CharacterEncodingFilter(ENCODING);
 		filter.doFilter(request, response, filterChain);
 
 		verify(request).setCharacterEncoding(ENCODING);