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>