GZIP：response压缩

来源：互联网发布：鲸蜡醇乙基己酸酯知乎编辑：程序博客网时间：2024/06/10 04:08

这里写图片描述

设置编码问题

response压缩

public class GzipFilter implements Filter {    public void init(FilterConfig filterConfig) throws ServletException {    }    public void doFilter(ServletRequest req, ServletResponse resp,            FilterChain chain) throws IOException, ServletException {        HttpServletRequest request;        HttpServletResponse response;        try{            request = (HttpServletRequest)req;            response = (HttpServletResponse)resp;        }catch(Exception e){            throw new RuntimeException("non-http request");        }        //对 response进行包装，为了能获取向浏览器写的数据        MyHttpServletResponse myresponse = new MyHttpServletResponse(response);        chain.doFilter(request, myresponse);        //压缩代码应放到放行后        byte b[] = myresponse.getBytes();//如何拿到原始的数据字节序列        System.out.println("压缩前大小："+b.length);        ByteArrayOutputStream out = new ByteArrayOutputStream();//内存数组流：缓存输出流        GZIPOutputStream gout = new GZIPOutputStream(out);        gout.write(b);        gout.close();//   压缩后的数据到ByteArrayOutputStream中了        b = out.toByteArray();//取出压缩后的数据        System.out.println("压缩后大小："+b.length);        //通知浏览器正文的压缩格式        response.setHeader("Content-Encoding", "gzip");             response.getOutputStream().write(b);    }    public void destroy() {    }}class MyHttpServletResponse extends HttpServletResponseWrapper{    private HttpServletResponse response;    private ByteArrayOutputStream baos = new ByteArrayOutputStream();//输出的数据    private PrintWriter pw;    public MyHttpServletResponse(HttpServletResponse response){        super(response);        this.response = response;    }    //字节流.覆盖该方法的目的，截获原始的数据:当外部调用getOutputStream()时，能获取输出流的内容数据    @Override    public ServletOutputStream getOutputStream() throws IOException {        return new MyServletOutputStream(baos);    }    //字符流输出  当外部调用getWriter()时，能获取输出流的内容数据    @Override    public PrintWriter getWriter() throws IOException {        pw = new PrintWriter(new OutputStreamWriter(baos, response.getCharacterEncoding()));        return pw;    }    /**     * 刷新存放缓存的字节流输出的数据，得到写入的数据     * @return     */    public byte[] getBytes(){        try {            if(pw!=null){                pw.close();            }                           baos.flush();        } catch (IOException e) {            e.printStackTrace();        }        return baos.toByteArray();    }}/** * 包装字节流 * @author zhangjianbin * */class MyServletOutputStream extends ServletOutputStream{    private ByteArrayOutputStream baos;    public MyServletOutputStream(ByteArrayOutputStream baos){        this.baos = baos;    }    //将外部的数据写入 ByteArrayOutputStream 存放缓存的字节流输出的数据    @Override    public void write(int b) throws IOException {        baos.write(b);    }}

public class ServletDemo1 extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        String data = "<h1>中中</h1>";        //response 是包装后的        ServletOutputStream sos = response.getOutputStream();        //调用了包装后的对象，这里是写入了自定义的内存缓存字节数组中去了        sos.write(data.getBytes("UTF-8"));//      byte b[] = data.getBytes();//      System.out.println("压缩前大小："+b.length);//      ByteArrayOutputStream out = new ByteArrayOutputStream();//内存数组流：缓存输出流//      GZIPOutputStream gout = new GZIPOutputStream(out);//      gout.write(b);//      gout.close();//   压缩后的数据到ByteArrayOutputStream中了//      //      //      b = out.toByteArray();//取出压缩后的数据//      System.out.println("压缩后大小："+b.length);//      //      //通知浏览器正文的压缩格式//      response.setHeader("Content-Encoding", "gzip");//      response.getOutputStream().write(b);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        doGet(request, response);    }}

0 0