org.springframework.web.filter.CharacterEncodingFilter Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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;
import org.springframework.lang.Nullable;
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
* encoding even if specified in the HTML page or form.
*
* 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 (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 {
@Nullable
private String encoding;
private boolean forceRequestEncoding = false;
private boolean forceResponseEncoding = 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) {
this(encoding, forceEncoding, forceEncoding);
}
/**
* Create a {@code CharacterEncodingFilter} for the given encoding.
* @param encoding the encoding to apply
* @param forceRequestEncoding whether the specified encoding is supposed to
* override existing request encodings
* @param forceResponseEncoding whether the specified encoding is supposed to
* override existing response encodings
* @since 4.3
* @see #setEncoding
* @see #setForceRequestEncoding(boolean)
* @see #setForceResponseEncoding(boolean)
*/
public CharacterEncodingFilter(String encoding, boolean forceRequestEncoding, boolean forceResponseEncoding) {
Assert.hasLength(encoding, "Encoding must not be empty");
this.encoding = encoding;
this.forceRequestEncoding = forceRequestEncoding;
this.forceResponseEncoding = forceResponseEncoding;
}
/**
* Set the encoding to use for requests. This encoding will be passed into a
* {@link javax.servlet.http.HttpServletRequest#setCharacterEncoding} call.
*
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(@Nullable String encoding) {
this.encoding = encoding;
}
/**
* Return the configured encoding for requests and/or responses.
* @since 4.3
*/
@Nullable
public String getEncoding() {
return this.encoding;
}
/**
* Set whether the configured {@link #setEncoding encoding} of this filter
* is supposed to override existing request and response encodings.
*
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.
*
This is the equivalent to setting both {@link #setForceRequestEncoding(boolean)}
* and {@link #setForceResponseEncoding(boolean)}.
* @see #setForceRequestEncoding(boolean)
* @see #setForceResponseEncoding(boolean)
*/
public void setForceEncoding(boolean forceEncoding) {
this.forceRequestEncoding = forceEncoding;
this.forceResponseEncoding = forceEncoding;
}
/**
* Set whether the configured {@link #setEncoding encoding} of this filter
* is supposed to override existing request encodings.
*
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.
* @since 4.3
*/
public void setForceRequestEncoding(boolean forceRequestEncoding) {
this.forceRequestEncoding = forceRequestEncoding;
}
/**
* Return whether the encoding should be forced on requests.
* @since 4.3
*/
public boolean isForceRequestEncoding() {
return this.forceRequestEncoding;
}
/**
* Set whether the configured {@link #setEncoding encoding} of this filter
* is supposed to override existing response encodings.
*
Default is "false", i.e. do not modify the encoding.
* Switch this to "true" to enforce the specified encoding
* for responses in any case.
* @since 4.3
*/
public void setForceResponseEncoding(boolean forceResponseEncoding) {
this.forceResponseEncoding = forceResponseEncoding;
}
/**
* Return whether the encoding should be forced on responses.
* @since 4.3
*/
public boolean isForceResponseEncoding() {
return this.forceResponseEncoding;
}
@Override
protected void doFilterInternal(
HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
String encoding = getEncoding();
if (encoding != null) {
if (isForceRequestEncoding() || request.getCharacterEncoding() == null) {
request.setCharacterEncoding(encoding);
}
if (isForceResponseEncoding()) {
response.setCharacterEncoding(encoding);
}
}
filterChain.doFilter(request, response);
}
}