Filter design implements IP address restrictions

Example: Create an IP filtering filter that, when a user makes an access request, is first judged by a filter,

If the user's IP address is restricted, access is forbidden and only legitimate IP can continue to access it. The IP Filtering filter code is as follows:

Ipfilter.java

1  PackageCOM.MHB;2 3 Importjava.io.IOException;4 ImportJava.io.PrintWriter;5 6 ImportJavax.servlet.Filter;7 ImportJavax.servlet.FilterChain;8 ImportJavax.servlet.FilterConfig;9 Importjavax.servlet.ServletException;Ten Importjavax.servlet.ServletRequest; One ImportJavax.servlet.ServletResponse; A  -  Public classIPFilterImplementsFilter { -  the protectedfilterconfig Filterconfig; - protectedString IP; -  -  Public voidInit (Filterconfig filterconfig)throwsservletexception { +  This. filterconfig = Filterconfig;//Set Property Filterconfig -  This. IP = This. Filterconfig.getinitparameter ("IP");//set initialization parameter IP + } A //Filtration Method at  Public voidDoFilter (servletrequest request, servletresponse response, -Filterchain chain)throwsIOException, servletexception { -String Remoteip = Request.getlocaladdr ();//Get the client IP address -  - if(Remoteip.equals (IP)) {//determine if IP is forbidden -Response.setcharacterencoding ("gb2312");//Setting the output content encoding format inPrintWriter out =Response.getwriter (); -Out.println ("<b> Your IP address is forbidden to access!") </b> "); to}Else{ + Chain.dofilter (request, response); - } the } * //Method of Destruction $  Public voiddestroy () {Panax Notoginseng } -}

Web. XML configuration

<filter>      <filter-name>IPFilter</filter-name>      <filter-class> com.mhb.ipfilter</filter-class>      <init-param>       <param-name>ip</param-name >       <param-value>127.0.0.1</param-value>      </init-param>  </filter>  < filter-mapping>       <filter-name>IPFilter</filter-name>       <url-pattern>/* </url-pattern>  </filter-mapping>  <welcome-file-list>    <welcome-file >index.jsp</welcome-file>  </welcome-file-list></web-app>

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Filter design implements IP address restrictions