采用Filter的方法解决Servlet的编码问题

这样比你自己在Servlet代码中硬编码request.setCharacterEncoding, response.setCharacterEncoding方便多了

总之，如果你添加了这个filter，配置好了web.xml，那么如果还出现乱码问题，你就去检查你的JSP和HTML代码中的encoding选项吧（charset, pageEncoding, meta.content之类的），看看是否和你在web.xml中配置的filter的encoding相匹配

CharacterEncodingFilter.java

 public class CharacterEncodingFilter implements Filter {
     protected String encoding = null;
     protected FilterConfig filterConfig = null;
     protected boolean enable = false;
     public void destroy() {
         this.encoding = null;
         this.filterConfig = null;
     }
     public void doFilter(ServletRequest request, ServletResponse response,
                            FilterChain chain) throws IOException, ServletException {
         if (this.enable) {
             String encoding = selectEncoding(request);
             if (encoding != null && !encoding.equals("")) {
                 System.out.println(this + ": ignore = true " + encoding);
                 request.setCharacterEncoding(encoding); //Overrides the name of the character encoding used in the body of this request. This method must be called prior to reading request parameters or reading input using getReader().
                 response.setCharacterEncoding(encoding);
             }
         }
         // Pass control on to the next filter
         chain.doFilter(request, response);
      }
      public void init(FilterConfig filterConfig) throws ServletException {
          this.filterConfig = filterConfig;
          this.encoding = filterConfig.getInitParameter("encoding");
          //
          String enable = filterConfig.getInitParameter("enable");
          if (enable.equalsIgnoreCase("true")) {
             this.enable = true;
          } else {
             this.enable = false;
          }
       }
       protected String selectEncoding(ServletRequest request) {
           return (this.encoding);
       }
 }

web.xml

<filter>
         <filter-name>charset-encoding</filter-name>
         <filter-class>cn.mldn.lxh.encoding.filter.CharacterEncodingFilter</filter-class>
         <init-param>
             <param-name>encoding</param-name>
             <param-value>UTF-8</param-value>
         </init-param>
         <init-param>
             <param-name>enable</param-name>
             <param-value>true</param-value>
         </init-param>
</filter>

<filter-mapping>
         <filter-name>charset-encoding</filter-name>
         <url-pattern>/*</url-pattern>
</filter-mapping>