【Java實現白名單及黑名單的Filter】

什麼是白名單及黑名單？

黑名單啓用後，被列入到黑名單的用戶（或IP地址、IP包、郵件、病毒等）不能經過。若是設立了白名單，則在白名單中的用戶（或IP地址、IP包、郵件等）會優先經過，不會被當成垃圾郵件拒收，安全性和快捷性都大大提升。

本文講解用java實現相似上述所說的攔截及經過功能的過濾連接。

好比我定義了一個mapping, 

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<servlet-mapping> <servlet-name>html_dispatcher</servlet-name> <url-pattern>*.html</url-pattern> </servlet-mapping>

就是說全部的.html請求都會由html_dispatcher來處理，但如今個人問題是： 
我但願某個文件夾下面的.html不用這個html_dispatcher處理，而全部其它的.html請求不變。 
由於把全部其它的.html列出來實在太多了，多到我都不知道有多少。因此不能一一列出。 
很明顯是在白名單裏邊排除一部分黑名單需求。
你們在開發Java Web時，在使用過濾器時是比較撓頭的，好比

 

 

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<filter-mapping>      <filter-name>TestFilter</filter-name>      <url-pattern>/*</url-pattern>  </filter-mapping>

1、前綴匹配   /user/*

2、後綴匹配  *.do

3、絕對匹配  /myservlet

 

並且若是我想過濾多個url必須

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<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>

兩個問題：

一、有的朋友可能須要過濾*.html 但要排除一部分（黑名單）；

二、有的朋友可能須要過濾多個url，如/a  /b，對於每個url必須寫一個filter-mapping比較繁瑣；

 

所以我寫了一個很是簡單的具有白名單和黑名單功能的基類Filter，過濾url使用Ant Path：

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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;  /**  * Ant語法  * 請參考 http://jinnianshilongnian.iteye.com/blog/1416322  *    *  配置方式     <filter>         <filter-name>TestFilter</filter-name>         <filter-class>com.sishuok.web.filter.TestFilter</filter-class>         <!-- url分隔符能夠是 換行 空格 分號  逗號  白名單和黑名單都是可選-->         <init-param>             <param-name>blackListURL</param-name> <!-- 配置黑名單url 表示不走過濾器的url order：1 -->             <param-value>                 /aa                 /bb/**                 /cc/*             </param-value>         </init-param>         <init-param>             <param-name>whiteListURL</param-name> <!-- 配置白名單url 表示走過濾器的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]";//逗號  空格 分號  換行          private final PathMatcher pathMatcher = new AntPathMatcher();          private final Logger logger = LoggerFactory.getLogger("url.filter");          /**      * 白名單      */      private String[] whiteListURLs = null;          /**      * 黑名單      */      private String[] blackListURLs = null;          @Override      public final void init(FilterConfig config) throws ServletException {          this.config = config;          this.initConfig();          this.init();      }          /**      * 子類覆蓋      *       * @throws ServletException      */      public void init() throws ServletException {          }          /**      * 一、黑名單匹配 二、白名單匹配      */      @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;      }          /**      * 子類覆蓋      *       * @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);      }          /**      * 子類覆蓋      */      @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;      }  }

具體使用以下：

 

 

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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 {//初始化          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() {//銷燬      }          }

xml配置以下：

 

 

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<filter>      <filter-name>TestFilter</filter-name>      <filter-class>com.sishuok.web.filter.TestFilter</filter-class>      <!-- url分隔符能夠是 換行 空格 分號  逗號  白名單和黑名單都是可選-->      <init-param>          <param-name>blackListURL</param-name> <!-- 配置黑名單url 表示不走過濾器的url order：1 -->          <param-value>              /aa              /bb/**              /cc/*          </param-value>      </init-param>      <init-param>          <param-name>whiteListURL</param-name> <!-- 配置白名單url 表示走過濾器的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>

由於相對來講實現很簡單，具體實現就不詳細介紹了。