com.feilong.servlet.http.ResponseUtil Maven / Gradle / Ivy
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/*
* Copyright (C) 2008 feilong
*
* 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 com.feilong.servlet.http;
import static com.feilong.core.CharsetType.UTF8;
import static com.feilong.core.Validator.isNotNullOrEmpty;
import static com.feilong.core.lang.ObjectUtil.defaultIfNullOrEmpty;
import static com.feilong.core.util.MapUtil.newHashMap;
import static com.feilong.core.util.MapUtil.newLinkedHashMap;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UncheckedIOException;
import java.util.Collection;
import java.util.Map;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.feilong.core.CharsetType;
import com.feilong.core.TimeInterval;
import com.feilong.core.Validate;
import com.feilong.io.entity.MimeType;
/**
* {@link javax.servlet.http.HttpServletResponse HttpServletResponse} 工具类.
*
* 关于 {@link RequestDispatcher#forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse) RequestDispatcher.forward} 和
* {@link HttpServletResponse#sendRedirect(String) HttpServletResponse.sendRedirect}
*
*
*
*
* {@link RequestDispatcher#forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse) RequestDispatcher.forward}
*
* {@link HttpServletResponse#sendRedirect(String) HttpServletResponse.sendRedirect}
*
*
* 只能将请求转发给同一个Web应用中的组件;
* 可以定向到应用程序外的其他资源.
*
*
* 重定向后URL不会改变;
* URL会改变
*
*
* 在服务器端内部将请求转发给另一个资源, 浏览器只知道发出请求并得到相应结果,并不知在服务器内部发生的转发行为
* 对浏览器的请求直接作出响应,响应的结果告诉浏览器重新发出对另外一个URL的访问请求
*
*
* 调用者与被调用者之间共享相同的request、response对象,它们属于同一个访问请求和相应过程;
* 调用者和被调用者使用各自的request、response对象,它们属于两个独立的访问请求和相应过程
*
*
* 适用于一次请求响应过程由Web程序内部的多个资源来协同完成, 需要在同一个Web程序内部资源之间跳转, 使用 {@link HttpServletRequest#setAttribute(String, Object)}方法将预处理结果传递给下一个资源.
* 适用于不同Web程序之间的重定向.
*
*
*
*
*
* 关于 {@link HttpServletResponse#sendRedirect(String)}:
*
*
*
* 用于生成302响应码和Location响应头,从而通知客户端重新访问Location响应头指定的URL.
*
*
*
* 在 {@link HttpServletResponse#sendRedirect(String)}之后,应该紧跟一句return;
* 我们已知道 {@link HttpServletResponse#sendRedirect(String)}是通过浏览器来做转向的,所以只有在页面处理完成后,才会有实际的动作.
* 既然您已要做转向了,那么后的输出更有什么意义呢？而且有可能会因为后面的输出导致转向失败.
*
*
*
* @author feilong
* @see javax.servlet.http.HttpServletResponse
* @since 1.0.0
*/
public final class ResponseUtil{
/** The Constant log. */
private static final Logger LOGGER = LoggerFactory.getLogger(ResponseUtil.class);
/** Don't let anyone instantiate this class. */
private ResponseUtil(){
//AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
//see 《Effective Java》 2nd
throw new AssertionError("No " + getClass().getName() + " instances for you!");
}
//---------------------------------------------------------------
/**
* 跳转.
*
*
* {@link HttpServletResponse#sendRedirect(String)}方法用于生成302响应码和Location响应头,从而通知客户端重新访问Location响应头指定的URL.
*
*
*
* 在 {@link HttpServletResponse#sendRedirect(String)}之后,应该紧跟一句return;;
* 我们已知道 {@link HttpServletResponse#sendRedirect(String)}是通过浏览器来做转向的,所以只有在页面处理完成后,才会有实际的动作.
* 既然您已要做转向了,那么后的输出更有什么意义呢？而且有可能会因为后面的输出导致转向失败.
*
*
*
* 如果 url 是null,抛出 {@link NullPointerException}
* 如果 url 是blank,抛出 {@link IllegalArgumentException}
*
*
* @param response
* the response
* @param url
* the redirect location URL
* @see HttpServletResponse#sendRedirect(String)
* @since 1.2.2
*/
public static void sendRedirect(HttpServletResponse response,String url){
Validate.notBlank(url, "url can't be blank!");
//---------------------------------------------------------------
try{
LOGGER.debug("response sendRedirect to:[{}]", url);
response.sendRedirect(url);
}catch (IOException e){
throw new UncheckedIOException(e);
}
}
//---------------------------------------------------------------
/**
* Sends an error response to the client using the specified status code and clears the buffer.
*
* The server will preserve cookies and may clear or update any headers needed to serve the error page as a valid response.
*
* If an error-page declaration has been made for the web application corresponding to the status code passed in, it will be served back
* the error page
*
*
* If the response has already been committed, this method throws an IllegalStateException.
* After using this method, the response should be considered to be committed and should not be written to.
*
* @param response
* the response
* @param errorStatusCode
* 错误码
* @since 1.11.5
* @exception IllegalStateException
* If the response was committed before this method call
*/
public static void sendError(HttpServletResponse response,int errorStatusCode){
sendError(response, errorStatusCode, "");
}
/**
* Sends an error response to the client using the specified
* status and clears the buffer. The server defaults to creating the
* response to look like an HTML-formatted server error page
* containing the specified message, setting the content type
* to "text/html". The server will preserve cookies and may clear or
* update any headers needed to serve the error page as a valid response.
*
* If an error-page declaration has been made for the web application
* corresponding to the status code passed in, it will be served back in
* preference to the suggested msg parameter and the msg parameter will
* be ignored.
*
*
* If the response has already been committed, this method throws
* an IllegalStateException.
* After using this method, the response should be considered
* to be committed and should not be written to.
*
* @param response
* the response
* @param errorStatusCode
* 错误码
* @param errorMessage
* the descriptive message
* @since 1.11.5
* @exception IllegalStateException
* If the response was committed before this method call
*/
public static void sendError(HttpServletResponse response,int errorStatusCode,String errorMessage){
Validate.notNull(errorMessage, "errorMessage can't be null!");
try{
LOGGER.debug("will sendError,errorStatusCode:[{}],errorMessage:[{}]", errorStatusCode, errorMessage);
response.sendError(errorStatusCode, errorMessage);
}catch (IOException e){
throw new UncheckedIOException(e);
}
}
//---------------------------------------------------------------
/**
* 设置页面不缓存.
*
*
* 当HTTP1.1服务器指定 CacheControl = no-cache时,浏览器就不会缓存该网页.
* 旧式 HTTP1.0 服务器不能使用 Cache-Control 标题
*
*
* 注意:
*
*
*
* 仅仅设置 Cache-Control:no-cache,如
*
*
*
* {@code
}
*
*
*
* 在 chrome 浏览器下面不起作用, 需要设置成 Cache-Control:no-cache,no-store,参见
* google-chrome-cache
*
*
*
* We see the same here: Chrome no cache需要 明确指定 no-store.如果不设置,那么 must-revalidate+ETag 没有效果, 并且 页面都会被 cached
* while they should not be since Chrome does not check for a 304 at all.
*
*
*
*
* @param response
* HttpServletResponse
* @see google-chrome-cache
* @see Cache doesnt adhear to No cache options(需要翻墙)
* @see
* chrome http_response_headers源码
* @see HttpHeaders#CACHE_CONTROL
* @see HttpHeaders#PRAGMA
* @see HttpHeaders#EXPIRES
*/
public static void setNoCacheHeader(HttpServletResponse response){
response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache,no-store,max-age=0");
response.setHeader(HttpHeaders.PRAGMA, "no-cache,no-store");
response.setDateHeader(HttpHeaders.EXPIRES, -1);
}
/**
* 设置页面缓存.
*
*
* 过期时间 = max-age 属性,单位秒.
*
*
* @param response
* the response
* @param cacheTime
* 过期时间 = max-age 属性,单位秒,建议使用{@link TimeInterval}里面定义的常量.
*
* if cacheTime {@code <=0} 表示不缓存
* 默认:0 不缓存
*
*
* 设置为int类型,int 最大值是{@link Integer#MAX_VALUE} 为 68.096259734906年,参见 {@link TimeInterval} ,绝对够用了
* @see HttpHeaders#CACHE_CONTROL
* @since 1.5.3
* @since 1.11.0 if cacheTime {@code <=0} 表示不缓存
*/
public static void setCacheHeader(HttpServletResponse response,int cacheTime){
if (cacheTime <= 0){
setNoCacheHeader(response);
}else{
response.setHeader(HttpHeaders.CACHE_CONTROL, "max-age=" + cacheTime);
}
}
// [start] PrintWriter
/**
* 以text的方式输出.
*
* @param response
* HttpServletResponse
* @param text
* text字符串
* @see #writeText(HttpServletResponse, Object, String)
* @see com.feilong.io.entity.MimeType#TXT
* @since 1.10.6
*/
public static void writeText(HttpServletResponse response,Object text){
writeText(response, text, UTF8);
}
/**
* 以text的方式输出.
*
* @param response
* HttpServletResponse
* @param text
* json字符串
* @param characterEncoding
* 编码
* 如果 characterEncoding 是null,抛出 {@link NullPointerException}
* 如果 characterEncoding 是blank,抛出 {@link IllegalArgumentException}
* @see #write(HttpServletResponse, Object, String, String)
* @see com.feilong.io.entity.MimeType#TXT
* @since 1.10.6
*/
public static void writeText(HttpServletResponse response,Object text,String characterEncoding){
Validate.notBlank(characterEncoding, "characterEncoding can't be blank!");
String contentType = MimeType.TXT.getMime() + ";charset=" + characterEncoding;
write(response, text, contentType, characterEncoding);
}
//---------------------------------------------------------------
/**
* 以json的方式输出.
*
* @param response
* HttpServletResponse
* @param json
* json字符串
* @see #writeJson(HttpServletResponse, Object, String)
* @see com.feilong.io.entity.MimeType#JSON
* @since 1.0.9
*/
public static void writeJson(HttpServletResponse response,Object json){
writeJson(response, json, UTF8);
}
/**
* 以json的方式输出.
*
* @param response
* HttpServletResponse
* @param json
* json字符串
* @param characterEncoding
* 编码
* 如果 characterEncoding 是null,抛出 {@link NullPointerException}
* 如果 characterEncoding 是blank,抛出 {@link IllegalArgumentException}
* @see #write(HttpServletResponse, Object, String, String)
* @see com.feilong.io.entity.MimeType#JSON
* @since 1.0.9
*/
public static void writeJson(HttpServletResponse response,Object json,String characterEncoding){
Validate.notBlank(characterEncoding, "characterEncoding can't be blank!");
String contentType = MimeType.JSON.getMime() + ";charset=" + characterEncoding;
write(response, json, contentType, characterEncoding);
}
//---------------------------------------------------------------
/**
* 输出.
*
* @param response
* HttpServletResponse
* @param content
* 相应内容
* @see javax.servlet.ServletResponse#getWriter()
* @see java.io.PrintWriter#print(Object)
* @see java.io.PrintWriter#flush()
* @see #write(HttpServletResponse, Object, String, String)
*/
public static void write(HttpServletResponse response,Object content){
String contentType = null;
String characterEncoding = UTF8;
write(response, content, contentType, characterEncoding);
}
/**
* 输出.
*
* @param response
* HttpServletResponse
* @param content
* 相应内容
* @param contentType
* 内容类型, 可以为null或者empty;
* 如果不为null或者empty,将会设置 {@link ServletResponse#setContentType(String)}
* @param characterEncoding
* 字符编码,建议使用 {@link CharsetType} 定义好的常量;
* 可以为null或者empty;
* 如果不为null或者empty,将会设置 {@link ServletResponse#setCharacterEncoding(String)}
* @see javax.servlet.ServletResponse#getWriter()
* @see java.io.PrintWriter#print(Object)
* @see java.io.PrintWriter#flush()
* @since 1.0.9
*/
public static void write(HttpServletResponse response,Object content,String contentType,String characterEncoding){
//编码 需要在 getWriter之前设置
if (isNotNullOrEmpty(contentType)){
response.setContentType(contentType);
}
response.setCharacterEncoding(defaultIfNullOrEmpty(characterEncoding, UTF8));
//---------------------------------------------------------------
try{
PrintWriter printWriter = response.getWriter();
printWriter.print(content);
printWriter.flush();
//http://www.iteye.com/problems/56543
//你是用了tomcat,jetty这样的容器,就不需要 printWriter.close()
}catch (IOException e){
throw new UncheckedIOException(e);
}
}
// [end]
//---------------------------------------------------------------
/**
* 获得 response info map for LOGGER.
*
* @param response
* the response
* @return the response info map for log
* @since 1.5.4
*/
public static Map getResponseInfoMapForLog(HttpServletResponse response){
Map map = newLinkedHashMap();
map.put("response.getBufferSize()", response.getBufferSize());
map.put("response.getCharacterEncoding()", response.getCharacterEncoding());
map.put("response.getContentType()", response.getContentType());
map.put("response headers", getResponseHeaderMap(response));
map.put("response.getLocale()", "" + response.getLocale());
return map;
}
/**
* 获得 response header map.
*
* @param response
* the response
* @return the response header map
* @since 1.6.3
*/
private static Map getResponseHeaderMap(HttpServletResponse response){
Collection headerNames = response.getHeaderNames(); //Servlet 3.0
Map map = newHashMap();
for (String headerName : headerNames){
map.put(headerName, response.getHeader(headerName)); //Servlet 3.0
}
return map;
}
}