copyrightfilter.java

详细讲述Servlet

package com.briup.filter;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

public class CopyrightFilter implements Filter {

	public void destroy() {
		// TODO Auto-generated method stub

	}

	public void doFilter(ServletRequest arg0, ServletResponse arg1,
			FilterChain chain) throws IOException, ServletException {
		HttpServletResponse response = 
				(HttpServletResponse)arg1;
		HttpServletResponseWrapper resw = 
			new CopyrightResponseWrapper(response);
		
		chain.doFilter(arg0, resw);
	
		String appString = 
			"<hr><center>Copyright (c) " +
			"Briup Inc 2007</center></body></html>";
		String buffer = resw.toString();
		int position = buffer.toLowerCase()
				.indexOf("</body></html>");
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		if(position > 0){
			String newString = 
					buffer.substring(0, position);
			newString += appString;
			out.println(newString);
		}else{
			out.println(buffer);
		}
		out.flush();
		out.close();
		
	}

	public void init(FilterConfig arg0) throws ServletException {
		// TODO Auto-generated method stub

	}

}