Java Encoding Filter

The role of 1.java coded filters:

Java filters can intercept requests and responses from target resources, and the filtering information executes more than Servlets.

Its newly added features include:
1. Application life cycle event control;
2. New Internationalization;
3. Clarification of the loading rules of the class;
4. New error and security attributes;
5. Does not endorse the use of the httputils category;
6. A variety of useful methods;
7. Clarified and expanded several servlet DTDs;
8. Filter function.

Use of 2.java filters:

(1) write a generic Java class that implements the filter interface

Import Java.io.ioexception;import Javax.servlet.filter;import javax.servlet.filterchain;import Javax.servlet.filterconfig;import Javax.servlet.servletexception;import Javax.servlet.servletrequest;import Javax.servlet.ServletResponse; Public classEcodefilter implements Filter {//define encoding By default is empty    PrivateString encoding =NULL;  Public voiddestroy () {}//Automatic Call filtering method DoFilter     Public voidDoFilter (servletrequest request, servletresponse response, Filterchain chain) throws IOException, Servlet Exception {//filter the data in the request if the encoding is not empty        if(Encoding! =NULL) {            //set the request character encodingrequest.setcharacterencoding (encoding); //Set Response character encodingResponse.setcontenttype ("text/html;charset="+encoding); }        //Pass to next filter or next servlet/jspChain.dofilter (request, response); }     Public voidinit (filterconfig config) throws servletexception {//The configuration code of the filter in Web. XML is removed to assign the value to encodingEncoding=config.getinitparameter ("encoding"); }}

　　

(2) Configuring filters in WEB.XM

<!--encoding filter, filter for all addresses--    <filter>        <filter-name>encodefilter  Filter Name </filter-name >        <filter-class>com.bw.shop.util.ecodefilter  Filter's fully qualified name </filter-class>        <init-param>            <param-name>encoding</param-name>            <param-value>utf-8</ param-value>        </init-param>    </filter>    <filter-mapping>        <filter-name >encodefilter  Filter Name </filter-name>        <url-pattern>/*  page address to be filtered </ url-pattern>    </filter-mapping>

Java Encoding Filter