问题引入:
比如定义了一个mapping,
<servlet-mapping> <servlet-name>html_dispatcher</servlet-name> <url-pattern>*.html</url-pattern> </servlet-mapping>
就是说所有的.html请求都会由html_dispatcher来处理,但现在的问题是:
我希望某个文件夹下面的.html不用这个html_dispatcher处理,而所有其它的.html请求不变。因为把所有其它的.html列出来实在太多了,多到我都不知道有多少。所以不能一一列出。
很明显,可以使用在白名单里排除一部分黑名单来实现。
大家在开发Java Web时,在使用过滤器时是比较挠头的,比如
<filter-mapping> <filter-name>TestFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
url-pattern只能是如下三种:
1、前缀匹配 /user/*
2、后缀匹配 *.do
3、绝对匹配 /myservlet
而且如果我想过滤多个url必须
<filter-mapping> <filter-name>TestFilter</filter-name> <url-pattern>/a</url-pattern> </filter-mapping> <filter-mapping> <filter-name>TestFilter</filter-name> <url-pattern>/b</url-pattern> </filter-mapping>
两个问题:
1、有的朋友可能需要过滤*.html 但要排除一部分(黑名单);
2、有的朋友可能需要过滤多个url,如/a /b,对于每一个url必须写一个filter-mapping比较繁琐;
因此我写了一个非常简单的具备白名单和黑名单功能的基类Filter,过滤url使用Ant Path:
package com.sishuok.web.filter;import java.io.IOException;import java.util.ArrayList;import java.util.List;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.util.AntPathMatcher;import org.springframework.util.PathMatcher;/** * * 配置方式 <filter> <filter-name>TestFilter</filter-name> <filter-class>com.sishuok.web.filter.TestFilter</filter-class> <!-- url分隔符可以是 换行 空格 分号 逗号 白名单和黑名单都是可选--> <init-param> <param-name>blackListURL</param-name> <!-- 配置黑名单url 表示不走过滤器的url order:1 --> <param-value> /aa /bb/** /cc/* </param-value> </init-param> <init-param> <param-name>whiteListURL</param-name> <!-- 配置白名单url 表示走过滤器的url order:2--> <param-value> /dd;/ee,/ff /list </param-value> </init-param> </filter> <filter-mapping> <filter-name>TestFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> * * @author Zhang Kaitao * */public abstract class BaseFilter implements Filter { private FilterConfig config = null; private final String[] NULL_STRING_ARRAY = new String[0]; private final String URL_SPLIT_PATTERN = "[, ;\r\n]"; private final PathMatcher pathMatcher = new AntPathMatcher(); private final Logger logger = LoggerFactory.getLogger("url.filter"); /** * 白名单 */ private String[] whiteListURLs = null; /** * 黑名单 */ private String[] blackListURLs = null; @Override public final void init(FilterConfig config) throws ServletException { this.config = config; this.initConfig(); this.init(); } /** * 子类覆盖 * * @throws ServletException */ public void init() throws ServletException { } /** * 1、黑名单匹配 2、白名单匹配 */ @Override public final void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpRequest = (HttpServletRequest) request; HttpServletResponse httpResponse = (HttpServletResponse) response; String currentURL = httpRequest.getServletPath(); logger.debug("url filter : current url : [{}]", currentURL); if (isBlackURL(currentURL)) { chain.doFilter(request, response); return; } if (isWhiteURL(currentURL)) { doFilter(httpRequest, httpResponse, chain); return; } logger.debug("url filter : no url list matches : [{}] break", currentURL); chain.doFilter(request, response); return; } private boolean isWhiteURL(String currentURL) { for (String whiteURL : whiteListURLs) { if (pathMatcher.match(whiteURL, currentURL)) { logger.debug("url filter : white url list matches : [{}] match [{}] continue", whiteURL, currentURL); return true; } logger.debug("url filter : white url list not matches : [{}] match [{}]", whiteURL, currentURL); } return false; } private boolean isBlackURL(String currentURL) { for (String blackURL : blackListURLs) { if (pathMatcher.match(blackURL, currentURL)) { logger.debug("url filter : black url list matches : [{}] match [{}] break", blackURL, currentURL); return true; } logger.debug("url filter : black url list not matches : [{}] match [{}]", blackURL, currentURL); } return false; } /** * 子类覆盖 * * @param request * @param response * @param chain * @throws IOException * @throws ServletException */ public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException { chain.doFilter(request, response); } /** * 子类覆盖 */ @Override public void destroy() { } private void initConfig() { String whiteListURLStr = this.config.getInitParameter("whiteListURL"); whiteListURLs = strToArray(whiteListURLStr); String blackListURLStr = this.config.getInitParameter("blackListURL"); blackListURLs = strToArray(blackListURLStr); } private String[] strToArray(String urlStr) { if (urlStr == null) { return NULL_STRING_ARRAY; } String[] urlArray = urlStr.split(URL_SPLIT_PATTERN); List<String> urlList = new ArrayList<String>(); for (String url : urlArray) { url = url.trim(); if (url.length() == 0) { continue; } urlList.add(url); } return urlList.toArray(NULL_STRING_ARRAY); } public FilterConfig getConfig() { return config; }}
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具体使用如下:
package com.sishuok.web.filter;import java.io.IOException;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class TestFilter extends BaseFilter { @Override public void init() throws ServletException { FilterConfig config = getConfig(); } @Override public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("=============="); chain.doFilter(request, response); } @Override public void destroy() { }}
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xml配置如下:
<filter> <filter-name>TestFilter</filter-name> <filter-class>com.sishuok.web.filter.TestFilter</filter-class> <init-param> <param-name>blackListURL</param-name> <param-value> /aa /bb/** /cc/* </param-value> </init-param> <init-param> <param-name>whiteListURL</param-name> <param-value> /dd;/ee,/ff /list </param-value> </init-param> </filter> <filter-mapping> <filter-name>TestFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
http://blog.csdn.net/lmb55/article/details/50639676
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