Fileter的创建

使用fileter进行编码

1：后台java代码：
 

     public class SetCharacterEncodingFilter implements Filter {

    public void destroy() {

        this.encoding = null;
        this.filterConfig = null;

    }

      public void doFilter(ServletRequest req, ServletResponse res,
                         FilterChain chain)
	throws IOException, ServletException {

    	HttpServletRequest request = (HttpServletRequest) req;
    	HttpServletResponse response = (HttpServletResponse) res;
		// Conditionally select and set the character encoding to be used
        if (ignore || (request.getCharacterEncoding() == null)) {
            String encoding = selectEncoding(request);
            if (encoding != null)
                request.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 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;

    }

       protected String selectEncoding(ServletRequest request) {

        return (this.encoding);

    }


   
  

2：web.xml

  <!-- 字符编码过滤 -->
	<filter>
		<filter-name>SetCharacterEncodingFilter</filter-name>
		<filter-class>
			com。。。.SetCharacterEncodingFilter
		</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>UTF-8</param-value>
		</init-param>
		<init-param>
			<param-name>ignore</param-name>
			<param-value>false</param-value>
		</init-param>

<filter-mapping>
		<filter-name>SetCharacterEncodingFilter</filter-name>
		<url-pattern>/jsp/*</url-pattern>
	</filter-mapping>
	<filter-mapping>
		<filter-name>SetCharacterEncodingFilter</filter-name>
		<url-pattern>*.do</url-pattern>
	</filter-mapping>