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; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
 
public class SetCharacterEncodingFilter implements Filter { //要實現(xiàn)Filter接口 
 //存儲編碼格式信息 
 private String encode = null; 
 public void destroy(){ 
  
 } 
  
 public void doFilter(ServletRequest req,ServletResponse resp,FilterChain chain) 
  throws IOException,ServletException{ 
  
 //轉(zhuǎn)換 
 HttpServletRequest request = (HttpServletRequest)req; 
 HttpServletResponse response = (HttpServletResponse)resp; 
  
 /* 
  * 判斷在web.xml文件中是否配置了編碼格式的信息 
  * 如果為空，則設(shè)置編碼格式為配置文件中的編碼格式 
  * 否則編碼格式設(shè)置為GBK 
  */ 
 if(this.encode != null && !this.encode.equals("")){ 
  request.setCharacterEncoding(this.encode); 
  response.setCharacterEncoding(this.encode); 
 }else{ 
  request.setCharacterEncoding("GBK"); 
  response.setCharacterEncoding("GBK"); 
 } 
  
 /* 
  * 使用doFilter方法調(diào)用鏈中的下一個過濾器或目標(biāo)資源（servlet或JSP頁面）。 
  * chain.doFilter處理過濾器的其余部分（如果有的話），最終處理請求的servlet或JSP頁面。 
  */ 
 chain.doFilter(request, response); 
 } 
  
 public void init(FilterConfig config) throws ServletException{ 
 //獲取在web.xml文件中配置了的編碼格式的信息 
 this.encode = config.getInitParameter("encode"); 
 } 
  
  
} 

<?xml version="1.0" encoding="UTF-8"?> 
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4" 
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee  http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 
 
 <!-- 過濾器配置信息 --> 
 <filter> 
 <filter-name>SetCharacterEncodingFilter</filter-name> 
 <!-- 過濾器設(shè)置編碼文件 --> 
 <filter-class> 
  ssh.dlc.chp1.filter.SetCharacterEncodingFilter 
 </filter-class> 
 <init-param> 
   <!-- 
    init-param元素定義了過濾器的初始化參數(shù) 
    --> 
  <description>給參數(shù)和值設(shè)置名稱和編碼類型</description> 
  <param-name>encode</param-name> 
  <param-value>GBK</param-value> 
 </init-param> 
 </filter> 
 <filter-mapping> 
 <!--  
  filter-mapping告訴容器所有與模式向匹配的請求都應(yīng)該允許通過訪問控制過濾器。 
  所有以.do結(jié)尾的訪問都先通過過濾器文件過濾  
 --> 
 <filter-name>SetCharacterEncodingFilter</filter-name> 
 <url-pattern>*.do</url-pattern> 
 </filter-mapping> 
</web-app>