capitalletterfilter.java

<Java网络程序设计 J2EE>随书源码

package jwadbook.filter;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.ServletException;
import java.io.*;
import java.util.Date;
import java.awt.*;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import java.awt.image.BufferedImage;

/**
 *
 * @author Jian (James) Cai
 */
public class CapitalLetterFilter implements Filter
{

    public void init(final FilterConfig filterConfig) 
    {

    }

    public void destroy()
    {

    }
    public CapitalLetterFilter() {
 
    }

    public void doFilter(final ServletRequest request, final ServletResponse response, FilterChain chain) throws java.io.IOException,
    javax.servlet.ServletException
    {
	String message = "Filtered !";
	GenericResponseWrapper wrapper = new GenericResponseWrapper((HttpServletResponse)response);
	chain.doFilter(request, wrapper);
	OutputStream out = response.getOutputStream();
	//message = getFilterConfig().getInitParameter("message");

	ByteArrayOutputStream respStream = manipulateResp(wrapper.output());
	response.setContentLength(respStream.size());
	response.setContentType("text/html");
	out.write(respStream.toByteArray());

	out.flush();
	out.close();
    }
    
    public ByteArrayOutputStream manipulateResp(byte[] respData) throws ServletException
    {
	//change every character in the response to higher case

	int i;
	int o;
	char a='a';
	char A='A';
	int diff = A-a;
	ByteArrayInputStream readStream;
	ByteArrayOutputStream respStream;
	respStream = new ByteArrayOutputStream();
	
	try{
	readStream = new ByteArrayInputStream(respData);
	
	do {
	    i = readStream.read();
	   
	    //log("get char:"+((char) i));
	    //log("FilterWRES 125: read readStream");
	    if (i != -1) 
		{
		    if ( (((char) i)>='a')&&(((char) i)<='z') )
			{
			    o= i+diff;
			    respStream.write(o);
			}
		    else
			{
			    respStream.write(i);
			}
		}
	} while (i != -1);
	
	readStream.close();
	
	}
	catch (IOException e)
	    {
		System.out.println("IOExcption:" + e);
	    }

	return respStream;
    }
}