关于过滤jsp内容的问题

Question

我现在想做一个过滤jsp特定内容的过滤器，不知道怎么做这个过滤器，请有做过的说明一下如何去做，我现在特别想知道，如何得到jsp的响应内容，如何将修改后的响应内容发送出去，还望高手指点

Answer 1

是啊，我也是想用过滤器的；但是有两个基本问题尚待解决：
1、如何得到jsp的响应内容，就是原始的内容；
2、如何将修改后的响应内容发送出去，送到响应端。

Answer 2

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.io.PrintWriter;public class CN_Filter implements Filter
{
    public void destroy()
    {
    }    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException
    {
        //用过滤器设置编码后再传给相应的servlet
        req.setCharacterEncoding("GBK");
        try
        {
        chain.doFilter(new RequestWrapper((HttpServletRequest) req), resp);
        }catch (Exception e)
        {
            PrintWriter out=resp.getWriter();
            out.println("<script>history.back();</script>");
            return;
        }
    }    public void init(FilterConfig config) throws ServletException
    {    }}2、这二个类,,在这个类里过滤import java.util.*;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;public class RequestWrapper extends HttpServletRequestWrapper {    //Map realParameters = new HashMap();    public RequestWrapper(HttpServletRequest request) {
        super(request);
    }    public String getParameter(String string){
        String value= super.getParameter(string);
        if(value!=null&&value.indexOf("script")!=-1){
            value=value.replaceAll("script","scri pt");
        }        return value;
    }}3、web.xml加上    <filter>
        <filter-name>CN_Filter</filter-name>
        <filter-class>CN_Filter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>CN_Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

Answer 3

多谢，我这儿也找到一个，从more servlets and jsp中摘录的，public void doFilter(ServletRequest request,
                     ServletResponse response,
                     FilterChain chain)
                         throws ServletException, IOException {
  CharArrayWrapper responseWrapper =
  new CharArrayWrapper((HttpServletResponse)response);
   // Invoke resource, accumulating output in the wrapper.
  chain.doFilter(request,responseWrapper);
  // Turn entire output into one big String.
  String responseString = responseWrapper.toString();
  // In output, replace all occurrences of target string
  // with replacement string.
  responseString =
            FilterUtils.replace(responseString,
             getTargetString(),
             getReplacementString());
  // Update the Content-Length header.
  updateHeaders(response, responseString);
  PrintWriter out = response.getWriter();
  out.write(responseString);
}