java字元編碼過濾器配置源碼

package com.common.utils;import javax.servlet.*;import java.io.IOException;public class SetCharacterEncodingFilter implements Filter {       protected String encoding = null;               //編碼方式       protected FilterConfig filterConfig = null;     //參數設定物件       rotected boolean ignore = true;                 //是否採用改編碼           //讀取兩個參數的值    public void init(FilterConfig filterConfig) throws ServletException {               this.filterConfig = filterConfig;              this.encoding = filterConfig.getInitParameter("encoding");              String value = filterConfig.getInitParameter("ignore");              if (value == null)                     this.ignore = true;              else if (value.equalsIgnoreCase("true"))                     this.ignore = true;              else if (value.equalsIgnoreCase("yes"))                     this.ignore = true;              else                     this.ignore = false;       }      //過濾處理，如果ignore為true，則使用該指定的編碼   public void doFilter(ServletRequest request, ServletResponse response,                     FilterChain chain) throws IOException, ServletException {               // 有條件地選擇設定字元編碼使用              if (ignore || (request.getCharacterEncoding() == null)) {                     String encoding = this.encoding;                     if (encoding != null)                            request.setCharacterEncoding(encoding);              }               chain.doFilter(request, response);        }       //銷毀時置空參數對象       public void destroy() {              this.encoding = null;              this.filterConfig = null;       }   }  web.xml配置：<filter>    <filter-name>SetCharacterEncodingFilter</filter-name>    <filter-class>com.web0248.filter.SetCharacterEncodingFilter</filter-class>       <init-param>   <!-- 定義編碼格式，我用的是utf-8 -->      <param-name>encoding</param-name>      <param-value>utf-8</param-value>    </init-param>       <init-param>    <!-- ignore參數是在過濾器類定義的 -->      <param-name>ignore</param-name>      <param-value>true</param-value>    </init-param></filter><filter-mapping>    <filter-name>SetCharacterEncodingFilter</filter-name>    <servlet-name>action</servlet-name></filter-mapping><filter-mapping>    <filter-name>SetCharacterEncodingFilter</filter-name>    <servlet-name>*.jsp</servlet-name></filter-mapping>}

補充說明：在web.xml檔案中，所有filter元素必須出現在任意filter-mapping元素之前，filter-mapping元素又必須出現在所有servlet或servlet-mapping元素之前。

從前到後的順序為：...→filter→filter-mapping→listener→servlet→servlet-mapping→...