1 /*
2 * Copyright 2002-2007 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.web.filter;
18
19 import java.io.IOException;
20
21 import javax.servlet.FilterChain;
22 import javax.servlet.ServletException;
23 import javax.servlet.http.HttpServletRequest;
24 import javax.servlet.http.HttpServletResponse;
25
26 import org.springframework.util.ClassUtils;
27
28 /**
29 * Servlet 2.3/2.4 Filter that allows one to specify a character encoding for
30 * requests. This is useful because current browsers typically do not set a
31 * character encoding even if specified in the HTML page or form.
32 *
33 * <p>This filter can either apply its encoding if the request does not
34 * already specify an encoding, or enforce this filter's encoding in any case
35 * ("forceEncoding"="true"). In the latter case, the encoding will also be
36 * applied as default response encoding on Servlet 2.4+ containers (although
37 * this will usually be overridden by a full content type set in the view).
38 *
39 * @author Juergen Hoeller
40 * @since 15.03.2004
41 * @see #setEncoding
42 * @see #setForceEncoding
43 * @see javax.servlet.http.HttpServletRequest#setCharacterEncoding
44 * @see javax.servlet.http.HttpServletResponse#setCharacterEncoding
45 */
46 public class CharacterEncodingFilter extends OncePerRequestFilter {
47
48 // Determine whether the Servlet 2.4 HttpServletResponse.setCharacterEncoding(String)
49 // method is available, for use in the "doFilterInternal" implementation.
50 private final static boolean responseSetCharacterEncodingAvailable = ClassUtils.hasMethod(
51 HttpServletResponse.class, "setCharacterEncoding", new Class[] {String.class});
52
53
54 private String encoding;
55
56 private boolean forceEncoding = false;
57
58
59 /**
60 * Set the encoding to use for requests. This encoding will be passed into a
61 * {@link javax.servlet.http.HttpServletRequest#setCharacterEncoding} call.
62 * <p>Whether this encoding will override existing request encodings
63 * (and whether it will be applied as default response encoding as well)
64 * depends on the {@link #setForceEncoding "forceEncoding"} flag.
65 */
66 public void setEncoding(String encoding) {
67 this.encoding = encoding;
68 }
69
70 /**
71 * Set whether the configured {@link #setEncoding encoding} of this filter
72 * is supposed to override existing request and response encodings.
73 * <p>Default is "false", i.e. do not modify the encoding if
74 * {@link javax.servlet.http.HttpServletRequest#getCharacterEncoding()}
75 * returns a non-null value. Switch this to "true" to enforce the specified
76 * encoding in any case, applying it as default response encoding as well.
77 * <p>Note that the response encoding will only be set on Servlet 2.4+
78 * containers, since Servlet 2.3 did not provide a facility for setting
79 * a default response encoding.
80 */
81 public void setForceEncoding(boolean forceEncoding) {
82 this.forceEncoding = forceEncoding;
83 }
84
85
86 protected void doFilterInternal(
87 HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
88 throws ServletException, IOException {
89
90 if (this.encoding != null && (this.forceEncoding || request.getCharacterEncoding() == null)) {
91 request.setCharacterEncoding(this.encoding);
92 if (this.forceEncoding && responseSetCharacterEncodingAvailable) {
93 response.setCharacterEncoding(this.encoding);
94 }
95 }
96 filterChain.doFilter(request, response);
97 }
98
99 }
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