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>