spring MVC 乱码问题
(转)
spring的字符集过滤通过用于处理项目中的乱码问题,该过滤器位于org.springframework.web.filter包中,指向类CharacterEncodingFilter,CharacterEncodingFilter源代码如下:
- /*
- * Copyright 2002-2007 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.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.springframework.web.filter;
- import java.io.IOException;
- import javax.servlet.FilterChain;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- /**
- * Servlet 2.3/2.4 Filter that allows one to specify a character encoding for
- * requests. This is useful because current browsers typically do not set a
- * character encoding even if specified in the HTML page or form.
- *
- * <p>This filter can either apply its encoding if the request does not
- * already specify an encoding, or enforce this filter's encoding in any case
- * ("forceEncoding"="true"). In the latter case, the encoding will also be
- * applied as default response encoding on Servlet 2.4+ containers (although
- * this will usually be overridden by a full content type set in the view).
- *
- * @author Juergen Hoeller
- * @since 15.03.2004
- * @see #setEncoding
- * @see #setForceEncoding
- * @see javax.servlet.http.HttpServletRequest#setCharacterEncoding
- * @see javax.servlet.http.HttpServletResponse#setCharacterEncoding
- */
- public class CharacterEncodingFilter extends OncePerRequestFilter {
- private String encoding;
- private boolean forceEncoding = false;
- /**
- * Set the encoding to use for requests. This encoding will be passed into a
- * {@link javax.servlet.http.HttpServletRequest#setCharacterEncoding} call.
- * <p>Whether this encoding will override existing request encodings
- * (and whether it will be applied as default response encoding as well)
- * depends on the {@link #setForceEncoding "forceEncoding"} flag.
- */
- public void setEncoding(String encoding) {
- this.encoding = encoding;
- }
- /**
- * Set whether the configured {@link #setEncoding encoding} of this filter
- * is supposed to override existing request and response encodings.
- * <p>Default is "false", i.e. do not modify the encoding if
- * {@link javax.servlet.http.HttpServletRequest#getCharacterEncoding()}
- * returns a non-null value. Switch this to "true" to enforce the specified
- * encoding in any case, applying it as default response encoding as well.
- * <p>Note that the response encoding will only be set on Servlet 2.4+
- * containers, since Servlet 2.3 did not provide a facility for setting
- * a default response encoding.
- */
- public void setForceEncoding(boolean forceEncoding) {
- this.forceEncoding = forceEncoding;
- }
- @Override
- protected void doFilterInternal(
- HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
- throws ServletException, IOException {
- if (this.encoding != null && (this.forceEncoding || request.getCharacterEncoding() == null)) {
- request.setCharacterEncoding(this.encoding);
- if (this.forceEncoding) {
- response.setCharacterEncoding(this.encoding);
- }
- }
- filterChain.doFilter(request, response);
- }
- }
上述代码显示,在配置字符集过滤器时可设定两个参数的值,如下:
l encoding:字符集,即将过滤到的request的字符集设置为encoding指定的值,如UTF-8等,相当于:
- request.setCharacterEncoding
l forceEncoding:字面意思是强制字符集,但你大可不必按字面意思理解,因为这个参数的值只不过是指定response的字符集是否也设置成encoding所指定的字符集,所以你可以选择设置为true或false,当值为true时,相当于
- request.setCharacterEncoding(“”);
- response.setCharacterEncoding(“”);
当值为false时,相当于:
- request.setCharacterEncoding(“”);
默认值为false。
示例:
- <filter>
- <filter-name>characterEncodingFilter</filter-name>
- <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
- <init-param>
- <param-name>encoding</param-name>
- <param-value>UTF-8</param-value>
- </init-param>
- <init-param>
- <param-name>forceEncoding</param-name>
- <param-value>true</param-value>
- </init-param>
- </filter>
- <filter-mapping>
- <filter-name>characterEncodingFilter</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
以上代码放置在web.xml中,相当于servlet中的:
- request.setCharacterEncoding("UTF-8");
- response.setCharacterEncoding("UTF-8");