CharacterEncodingFilter-Spring字符编码过滤器

java.lang.Object
  extended by org.springframework.web.filter.GenericFilterBean
      extended by org.springframework.web.filter.OncePerRequestFilter
          extended by org.springframework.web.filter.CharacterEncodingFilter

 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 import javax.servlet.FilterChain;
21 import javax.servlet.ServletException;
22 import javax.servlet.http.HttpServletRequest;
23 import javax.servlet.http.HttpServletResponse;
24 
25 /**
26  * Servlet 2.3/2.4 Filter that allows one to specify a character encoding for
27  * requests. This is useful because current browsers typically do not set a
28  * character encoding even if specified in the HTML page or form.
29  *
30  * <p>This filter can either apply its encoding if the request does not
31  * already specify an encoding, or enforce this filter‘s encoding in any case
32  * ("forceEncoding"="true"). In the latter case, the encoding will also be
33  * applied as default response encoding on Servlet 2.4+ containers (although
34  * this will usually be overridden by a full content type set in the view).
35  *
36  * @author Juergen Hoeller
37  * @since 15.03.2004
38  * @see #setEncoding
39  * @see #setForceEncoding
40  * @see javax.servlet.http.HttpServletRequest#setCharacterEncoding
41  * @see javax.servlet.http.HttpServletResponse#setCharacterEncoding
42  */
43 public class CharacterEncodingFilter extends OncePerRequestFilter {
44 
45     private String encoding;
46 
47     private boolean forceEncoding = false;
48 
49 
50     /**
51      * Set the encoding to use for requests. This encoding will be passed into a
52      * {@link javax.servlet.http.HttpServletRequest#setCharacterEncoding} call.
53      * <p>Whether this encoding will override existing request encodings
54      * (and whether it will be applied as default response encoding as well)
55      * depends on the {@link #setForceEncoding "forceEncoding"} flag.
56      */
57     public void setEncoding(String encoding) {
58         this.encoding = encoding;
59     }
60 
61     /**
62      * Set whether the configured {@link #setEncoding encoding} of this filter
63      * is supposed to override existing request and response encodings.
64      * <p>Default is "false", i.e. do not modify the encoding if
65      * {@link javax.servlet.http.HttpServletRequest#getCharacterEncoding()}
66      * returns a non-null value. Switch this to "true" to enforce the specified
67      * encoding in any case, applying it as default response encoding as well.
68      * <p>Note that the response encoding will only be set on Servlet 2.4+
69      * containers, since Servlet 2.3 did not provide a facility for setting
70      * a default response encoding.
71      */
72     public void setForceEncoding(boolean forceEncoding) {
73         this.forceEncoding = forceEncoding;
74     }
75 
76 
77     @Override
78     protected void doFilterInternal(
79             HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
80             throws ServletException, IOException {
81 
82         if (this.encoding != null && (this.forceEncoding || request.getCharacterEncoding() == null)) {
83             request.setCharacterEncoding(this.encoding);
84             if (this.forceEncoding) {
85                 response.setCharacterEncoding(this.encoding);
86             }
87         }
88         filterChain.doFilter(request, response);
89     }
90 
91 }

 1      <filter>
 2         <filter-name>characterEncodingFilter</filter-name>
 3         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
 4         <init-param>
 5             <param-name>encoding</param-name>
 6             <param-value>UTF-8</param-value>
 7         </init-param>
 8         <init-param>
 9             <param-name>forceEncoding</param-name>
10             <param-value>true</param-value>
11         </init-param>
12       </filter>
13       <filter-mapping>
14         <filter-name>characterEncodingFilter</filter-name>
15         <url-pattern>/*</url-pattern>
16     </filter-mapping>