org.springframework.web.servlet.view.RedirectView Maven / Gradle / Ivy
/*
* 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.servlet.view;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.core.JdkVersion;
/**
* View that redirects to an absolute, context relative, or current request
* relative URL, exposing all model attributes as HTTP query parameters.
*
*
A URL for this view is supposed to be a HTTP redirect URL, i.e.
* suitable for HttpServletResponse's sendRedirect method, which
* is what actually does the redirect if the HTTP 1.0 flag is on, or via sending
* back an HTTP 303 code - if the HTTP 1.0 compatibility flag is off.
*
*
Note that while the default value for the "contextRelative" flag is off,
* you will probably want to almost always set it to true. With the flag off,
* URLs starting with "/" are considered relative to the web server root, while
* with the flag on, they are considered relative to the web application root.
* Since most web apps will never know or care what their context path actually
* is, they are much better off setting this flag to true, and submitting paths
* which are to be considered relative to the web application root.
*
*
Note that in a Servlet 2.2 environment, i.e. a servlet container which
* is only compliant to the limits of this spec, this class will probably fail
* when feeding in URLs which are not fully absolute, or relative to the current
* request (no leading "/"), as these are the only two types of URL that
* sendRedirect supports in a Servlet 2.2 environment.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Colin Sampaleanu
* @see #setContextRelative
* @see #setHttp10Compatible
* @see javax.servlet.http.HttpServletResponse#sendRedirect
*/
public class RedirectView extends AbstractUrlBasedView {
/** The default encoding scheme: UTF-8 */
public static final String DEFAULT_ENCODING_SCHEME = "UTF-8";
private boolean contextRelative = false;
private boolean http10Compatible = true;
private String encodingScheme = DEFAULT_ENCODING_SCHEME;
/**
* Constructor for use as a bean.
*/
public RedirectView() {
}
/**
* Create a new RedirectView with the given URL.
*
The given URL will be considered as relative to the web server,
* not as relative to the current ServletContext.
* @param url the URL to redirect to
* @see #RedirectView(String, boolean)
*/
public RedirectView(String url) {
super(url);
}
/**
* Create a new RedirectView with the given URL.
* @param url the URL to redirect to
* @param contextRelative whether to interpret the given URL as
* relative to the current ServletContext
*/
public RedirectView(String url, boolean contextRelative) {
super(url);
this.contextRelative = contextRelative;
}
/**
* Create a new RedirectView with the given URL.
* @param url the URL to redirect to
* @param contextRelative whether to interpret the given URL as
* relative to the current ServletContext
* @param http10Compatible whether to stay compatible with HTTP 1.0 clients
*/
public RedirectView(String url, boolean contextRelative, boolean http10Compatible) {
super(url);
this.contextRelative = contextRelative;
this.http10Compatible = http10Compatible;
}
/**
* Set whether to interpret a given URL that starts with a slash ("/")
* as relative to the current ServletContext, i.e. as relative to the
* web application root.
*
Default is "false": A URL that starts with a slash will be interpreted
* as absolute, i.e. taken as-is. If true, the context path will be
* prepended to the URL in such a case.
* @see javax.servlet.http.HttpServletRequest#getContextPath
*/
public void setContextRelative(boolean contextRelative) {
this.contextRelative = contextRelative;
}
/**
* Set whether to stay compatible with HTTP 1.0 clients.
*
In the default implementation, this will enforce HTTP status code 302
* in any case, i.e. delegate to HttpServletResponse.sendRedirect.
* Turning this off will send HTTP status code 303, which is the correct
* code for HTTP 1.1 clients, but not understood by HTTP 1.0 clients.
*
Many HTTP 1.1 clients treat 302 just like 303, not making any
* difference. However, some clients depend on 303 when redirecting
* after a POST request; turn this flag off in such a scenario.
* @see javax.servlet.http.HttpServletResponse#sendRedirect
*/
public void setHttp10Compatible(boolean http10Compatible) {
this.http10Compatible = http10Compatible;
}
/**
* Set the encoding scheme for this view. Default is UTF-8.
*/
public void setEncodingScheme(String encodingScheme) {
this.encodingScheme = encodingScheme;
}
/**
* Convert model to request parameters and redirect to the given URL.
* @see #appendQueryProperties
* @see #sendRedirect
*/
protected final void renderMergedOutputModel(
Map model, HttpServletRequest request, HttpServletResponse response) throws IOException {
// Prepare target URL.
StringBuffer targetUrl = new StringBuffer();
if (this.contextRelative && getUrl().startsWith("/")) {
// Do not apply context path to relative URLs.
targetUrl.append(request.getContextPath());
}
targetUrl.append(getUrl());
appendQueryProperties(targetUrl, model, this.encodingScheme);
sendRedirect(request, response, targetUrl.toString(), this.http10Compatible);
}
/**
* Append query properties to the redirect URL.
* Stringifies, URL-encodes and formats model attributes as query properties.
* @param targetUrl the StringBuffer to append the properties to
* @param model Map that contains model attributes
* @param encodingScheme the encoding scheme to use
* @throws UnsupportedEncodingException if string encoding failed
* @see #queryProperties
*/
protected void appendQueryProperties(StringBuffer targetUrl, Map model, String encodingScheme)
throws UnsupportedEncodingException {
// Extract anchor fragment, if any.
// The following code does not use JDK 1.4's StringBuffer.indexOf(String)
// method to retain JDK 1.3 compatibility.
String fragment = null;
int anchorIndex = targetUrl.toString().indexOf('#');
if (anchorIndex > -1) {
fragment = targetUrl.substring(anchorIndex);
targetUrl.delete(anchorIndex, targetUrl.length());
}
// If there aren't already some parameters, we need a "?".
boolean first = (getUrl().indexOf('?') < 0);
Iterator entries = queryProperties(model).entrySet().iterator();
while (entries.hasNext()) {
if (first) {
targetUrl.append('?');
first = false;
}
else {
targetUrl.append('&');
}
Map.Entry entry = (Map.Entry) entries.next();
String encodedKey = urlEncode(entry.getKey().toString(), encodingScheme);
String encodedValue =
(entry.getValue() != null ? urlEncode(entry.getValue().toString(), encodingScheme) : "");
targetUrl.append(encodedKey).append('=').append(encodedValue);
}
// Append anchor fragment, if any, to end of URL.
if (fragment != null) {
targetUrl.append(fragment);
}
}
/**
* URL-encode the given input String with the given encoding scheme.
*
Default implementation uses URLEncoder.encode(input, enc)
* on JDK 1.4+, falling back to URLEncoder.encode(input)
* (which uses the platform default encoding) on JDK 1.3.
* @param input the unencoded input String
* @param encodingScheme the encoding scheme
* @return the encoded output String
* @throws UnsupportedEncodingException if thrown by the JDK URLEncoder
* @see java.net.URLEncoder#encode(String, String)
* @see java.net.URLEncoder#encode(String)
*/
protected String urlEncode(String input, String encodingScheme) throws UnsupportedEncodingException {
if (JdkVersion.getMajorJavaVersion() < JdkVersion.JAVA_14) {
if (logger.isDebugEnabled()) {
logger.debug("Only JDK 1.3 URLEncoder available: using platform default encoding " +
"instead of the requested scheme '" + encodingScheme + "'");
}
return URLEncoder.encode(input);
}
return URLEncoder.encode(input, encodingScheme);
}
/**
* Determine name-value pairs for query strings, which will be stringified,
* URL-encoded and formatted by appendQueryProperties.
*
This implementation returns all model elements as-is.
* @see #appendQueryProperties
*/
protected Map queryProperties(Map model) {
return model;
}
/**
* Send a redirect back to the HTTP client
* @param request current HTTP request (allows for reacting to request method)
* @param response current HTTP response (for sending response headers)
* @param targetUrl the target URL to redirect to
* @param http10Compatible whether to stay compatible with HTTP 1.0 clients
* @throws IOException if thrown by response methods
*/
protected void sendRedirect(
HttpServletRequest request, HttpServletResponse response, String targetUrl, boolean http10Compatible)
throws IOException {
if (http10Compatible) {
// Always send status code 302.
response.sendRedirect(response.encodeRedirectURL(targetUrl));
}
else {
// Correct HTTP status code is 303, in particular for POST requests.
response.setStatus(303);
response.setHeader("Location", response.encodeRedirectURL(targetUrl));
}
}
}