Web Compression Filters

Web Compression Filters

Package mytest.gzipfilter;

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.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse;

Import Javax.servlet.http.HttpServletResponseWrapper;

/**

* Servlet Filter Implementation class Gzipfilter

*/

public class Gzipfilter implements Filter {

/**

* Default constructor.

*/

Public Gzipfilter () {

//TODO auto-generated constructor stub

}

/**

* @see Filter#destroy ()

*/

public void Destroy () {

//TODO auto-generated method stub

}

/**

* @see filter#dofilter (servletrequest, Servletresponse, Filterchain)

*/

public void DoFilter (ServletRequest req, servletresponse Res,

Filterchain chain) throws IOException, Servletexception {

//TODO auto-generated method stub

//Place your code here

httpservletrequest request = (httpservletrequest) req;

HttpServletResponse response = (httpservletresponse) res;

bufferhttpresponse bufferhttpresponse = new Bufferhttpresponse (response);

//Pass the request along the filter chain

chain.dofilter (Request, bufferhttpresponse);

byte out[] = Bufferhttpresponse.getbuffer ();

Bytearrayoutputstream bout = new Bytearrayoutputstream ();

Gzipoutputstream gout = new Gzipoutputstream (bout);

Gout.write (out);

gout.close ();

byte gzip[] = Bout.tobytearray ();

response.setheader ("content-encoding", "gzip");

response.setcontentlength (gzip.length);

Response.getoutputstream (). write (gzip);

}

/**

* @see filter#init (filterconfig)

*/

public void init (Filterconfig fconfig) throws Servletexception {

//TODO auto-generated method stub

}

}

Class Bufferhttpresponse extends Httpservletresponsewrapper {

Private HttpServletResponse response;

private Bytearrayoutputstream bout = new Bytearrayoutputstream ();

private PrintWriter pw;

Public Bufferhttpresponse (httpservletresponse response) {

Super (response);

this.response = response;

}

@Override

public Servletoutputstream Getoutputstream () throws IOException {

return new Myservletoutputstream (bout);

}

@Override

public PrintWriter getwriter () throws IOException {

pw = new PrintWriter (New OutputStreamWriter (Bout,this.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 Myservletoutputstream extends Servletoutputstream {

private Bytearrayoutputstream bout;

public Myservletoutputstream (Bytearrayoutputstream bout) {

this.bout = bout;

}

@Override

public void write (int arg0) throws IOException {

}

}

Configuring compressed content in Web. xml

<filter>

<display-name>GzipFilter</display-name>

<filter-name>GzipFilter</filter-name>

<filter-class>mytest.gzipfilter.GzipFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>GzipFilter</filter-name>

<url-pattern>/*.jsp</url-pattern>

<dispatcher>FORWARD</dispatcher>

<dispatcher>REQUEST</dispatcher>

</filter-mapping>

<filter-mapping>

<filter-name>GzipFilter</filter-name>

<url-pattern>/*.css</url-pattern>

</filter-mapping>

<filter-mapping>

<filter-name>GzipFilter</filter-name>

<url-pattern>/*.js</url-pattern>

</filter-mapping>

<filter-mapping>

<filter-name>GzipFilter</filter-name>

<url-pattern>/*.html</url-pattern>

</filter-mapping>

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Web Compression Filters