Filter技术实现全网站的压缩输出_filter 对输出页面压缩-优快云博客

本文介绍了一个使用Java实现的GZIP过滤器，该过滤器能够对接收到的HTTP响应进行GZIP压缩，从而减少数据传输量。通过继承`ServletResponseWrapper`创建了自定义响应类`MyResponse`，并实现了压缩逻辑。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

package com.filter;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.zip.GZIPOutputStream;

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

public class GZIPFilter implements Filter {

	@Override
	public void doFilter(ServletRequest req, ServletResponse resp,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
		HttpServletResponse response = (HttpServletResponse) resp;
		
		
		MyResponse myResponse = new MyResponse(response);
		chain.doFilter(request, myResponse);
		
		byte[] out = myResponse.getBuffer();
		
		ByteArrayOutputStream bout = new ByteArrayOutputStream();
		GZIPOutputStream gout = new GZIPOutputStream(bout);
		gout.write(out);
	
		byte gzip[] = bout.toByteArray();
		response.setHeader("content-encoding", "gzip");
		response.setContentLength(gzip.length);
		
		response.getOutputStream().write(gzip);
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
	}
	@Override
	public void destroy() {
	}

}

class MyResponse  extends  ServletResponseWrapper{
	private ByteArrayOutputStream bout = new ByteArrayOutputStream();
	
	PrintWriter pw ;
	private HttpServletResponse response;
	public MyResponse(HttpServletResponse response) {
		super(response);
		this.response = response;
	}
	@Override
	public ServletOutputStream getOutputStream() throws IOException {
		return new MyServletOutputStrem(bout);
	}
	@Override
	public PrintWriter getWriter() throws IOException {
		pw = new PrintWriter(new OutputStreamWriter(bout,response.getCharacterEncoding()));
		return pw;
	}
	
	public byte[] getBuffer(){
		try{
			if(pw != null){
				pw.close();
			}
			if(bout!=null){
				bout.flush();	
			}
			return bout.toByteArray();
		}catch(Exception e){
			throw new RuntimeException(e);
		}
	}
}
class MyServletOutputStrem extends ServletOutputStream{
	private ByteArrayOutputStream bout;
	
	public MyServletOutputStrem(ByteArrayOutputStream bout) {
		this.bout = bout;
	}

	@Override
	public void write(int b) throws IOException {
		this.bout.write(b);	
	}
}