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全站压缩

时间:2014-07-06 08:44:42      阅读:137      评论:0      收藏:0      [点我收藏+]

标签:des   style   http   java   数据   os   


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;
//全站压缩过滤器
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);//放行
//压缩代码写在此处
//找一个内存缓冲字节流
ByteArrayOutputStream baos = new ByteArrayOutputStream();
//把数据压缩到缓冲字节流流中
GZIPOutputStream gout = new GZIPOutputStream(baos);
//取出数据:压缩后的
byte b[] = gresponse.getOldBytes();//原始字节
System.out.println("原有数据大小:"+b.length);
gout.write(b);
gout.close();//保证所有的数据都进入内存缓存流

//取出压缩后的数据
b = baos.toByteArray();
System.out.println("压缩后的数据大小:"+b.length);
//输出前一定要告知客户端压缩方式
response.setHeader("Content-Encoding", "gzip");
response.setContentLength(b.length);//告知客户端正文的大小
//用服务器的响应对象输出
ServletOutputStream out = response.getOutputStream();
out.write(b);
}


public void init(FilterConfig filterConfig) throws ServletException {


}


}
class GzipHttpServletResponse extends HttpServletResponseWrapper{
private ByteArrayOutputStream baos = new ByteArrayOutputStream();
private PrintWriter pw;
public GzipHttpServletResponse(HttpServletResponse response){
super(response);
}
//把原始数据封装到一个缓冲流中
@Override
public ServletOutputStream getOutputStream() throws IOException {
return new MyServletOutputStream(baos);
}

//字符流:把原始数据封装到一个缓冲流中
@Override
public PrintWriter getWriter() throws IOException {
pw = new PrintWriter(new OutputStreamWriter(baos, super.getCharacterEncoding()));//字符流转成字节流编码会丢失
return pw;
}
//返回baos中的缓存数据:原始
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);
}
}

全站压缩,布布扣,bubuko.com

全站压缩

标签:des   style   http   java   数据   os   

原文地址:http://blog.csdn.net/u013032887/article/details/36903293

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