servlet经典实例 编码过滤器

 

1  web.xml的过滤器配置

 

<filter>
<filter-name>EncodingFilter</filter-name>
<filter-class>com.utils. EncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>gb2312</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>EncodingFilter</filter-name>
<url-pattern>/*</url-pattern> </filter-mapping>

2  EncodingFilter.java

 

package com.utils;
import javax.servlet.*;
import javax.servlet.http.*;
public class EncodingFilter extends HttpServlet implements Filter {
     private FilterConfig config = null;
     private String encoding = "";
     public void init(FilterConfig config) throws ServletException {
           this.config = config;
           this.encoding = config.getInitParameter("encoding");
     }
     public void doFilter(ServletRequest request, ServletResponseresponse, FilterChain chain) throws java.io.IOException, ServletException {
     HttpServletRequest req = (HttpServletRequest)request;
     HttpServletResponse res = (HttpServletResponse)response;
     response.setCharacterEncoding(this.encoding);
     java.io.PrintWriter out = res.getWriter();
     out.print("过滤器设置编码为："+this.encoding+""); chain.doFilter(req, res);
}
}

这样 每个页面的最前面都会出现一句话 过滤器设置编码为gb2312