Full site Compression

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. httpservletrequestwrapper;
Import javax. servlet. http. httpservletresponse;
Import javax. servlet. http. httpservletresponsewrapper;
// Full-site compression filter
Public class gzipfilter implements filter {


Public void destroy (){


}


Public void dofilter (servletrequest req, servletresponse resp,
Filterchain chain) throws ioexception, servletexception {
Httpservletrequest request = (httpservletrequest) req;
Httpservletresponse response = (httpservletresponse) resp;
Gziphttpservletresponse gresponse = new gziphttpservletresponse (response );
Chain. dofilter (request, gresponse); // allow
// Write the compressed code here
// Find a buffer byte stream in the memory
Bytearrayoutputstream baos = new bytearrayoutputstream ();
// Compress data into a buffer byte stream
Gzipoutputstream gout = new gzipoutputstream (baos );
// Retrieve data: Compressed
Byte B [] = gresponse. getoldbytes (); // original bytes
System. Out. println ("original data size:" + B. Length );
Gout. Write (B );
Gout. Close (); // ensure that all data enters the memory cache stream

// Extract the compressed data
B = baos. tobytearray ();
System. Out. println ("compressed data size:" + B. Length );
// Inform the client of the compression method before output
Response. setheader ("content-encoding", "gzip ");
Response. setcontentlength (B. Length); // tell the client body size
// Output with the response object of the server
Servletoutputstream out = response. getoutputstream ();
Out. Write (B );
}


Public void Init (filterconfig) throws servletexception {


}


}
Class gziphttpservletresponse extends httpservletresponsewrapper {
Private bytearrayoutputstream baos = new bytearrayoutputstream ();
Private printwriter PW;
Public gziphttpservletresponse (httpservletresponse response ){
Super (response );
}
// Encapsulate the raw data into a buffer stream
@ Override
Public servletoutputstream getoutputstream () throws ioexception {
Return new myservletoutputstream (baos );
}

// Volume stream: encapsulate raw data into a buffer stream
@ Override
Public printwriter getwriter () throws ioexception {
PW = new printwriter (New outputstreamwriter (baos, super. getcharacterencoding (); // bytes streams converted into byte stream encoding will be lost
Return PW;
}
// Return the cache data in baos: original
Public byte [] getoldbytes (){
Try {
If (PW! = NULL ){
PW. Close ();
}
Baos. Flush ();
} Catch (ioexception e ){
E. printstacktrace ();
}
Return baos. tobytearray ();
}

}
Class myservletoutputstream extends servletoutputstream {
Private bytearrayoutputstream baos;
Public myservletoutputstream (bytearrayoutputstream baos ){
This. baos = baos;
}
@ Override
Public void write (int B) throws ioexception {
Baos. Write (B );
}
}