Java compressed files and download pictures sample _java

This example for you to share the Java compressed files and download pictures samples for your reference, the specific contents are as follows

Main Page Index.xml

<%@ page language= "java" import= "java.util.*" pageencoding= "Utf-8"%>

 
 

Compressed file: Gzipservlet.java
Only compressed files are large enough to offset the compression overhead and effectively compress. Otherwise, the file size becomes larger after the small file is compressed

Package cn.hncu.servlet;
Import Java.io.ByteArrayOutputStream;
Import java.io.IOException;
Import Java.io.OutputStream;

Import Java.util.zip.GZIPOutputStream;
Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse; public class Gzipservlet extends HttpServlet {@Override protected void service (HttpServletRequest req, httpservletre Sponse resp) throws Servletexception, IOException {String str= "vuttyjhgyurc Hunan Changsha surdivsf Anhui Wuhu 890-80897 Maybe longer v will get used to it. Tvsduvgkjxhvnxzc.nlkcjsdfpeifniuq4ey8f048eyuyli "+"
Skchkxhckxzncnxclkjhasliduhasiduisugdlisgdlkjadhlksjhdlkasjdhasklhdlkjsahashdkskdjhkdjshkldsjhlksjhfkljd ";

    Byte src[]=str.getbytes (),//using Platform default encoding (GBK), no use of iso-8859-1 byte src[]=str.getbytes ("Utf-8"); Background to the browser sent data, browsers do not know-need to download, with text to open is garbled. So to set the protocol Bytearrayoutputstream bout=new Bytearrayoutputstream ();//Memory stream Gzipoutputstream gout=new gzipoutputstReam (BOut); Gout.write (SRC);//pressing SRC to BOut gout.close ()//Brush Cache byte Dest[]=bout.tobytearray ();//src==>dest//Summary: Set when output compresses data
    Response Head Resp.setheader ("content-encoding", "gzip"); After setting the response head, there is no need to download, not garbled Resp.setcontenttype ("text/html;charset=utf-8");//Be sure to set the Str.getbyte code//When the file is very small: compression no effect, but the burden (can not be offset Cost to eliminate compression) ...
    Larger files will be compressed (generally >200k) System.out.println ("Length before compression:" +src.length);
    SYSTEM.OUT.PRINTLN ("Compressed length:" +dest.length);
After compressing the data dest brush out OutputStream out=resp.getoutputstream ();//resp.getwriter ();
    Out.write (SRC);

  Out.write (dest);
 }

}

Download Picture: Downservlet. java (picture under SRC directory)

Package cn.hncu.servlet;
Import java.io.IOException;
Import Java.io.InputStream;
Import Java.io.OutputStream;

Import Java.net.URLEncoder;
Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse; public class Downservlet extends HttpServlet {@Override protected void service (HttpServletRequest req, httpservletre Sponse resp) throws Servletexception, IOException {//Protocol Setup 1 Resp.setcontenttype ("Application/force-download"
    //////////download String filename= "4.jpg" with the application of the default download file;
    If the filename is in Chinese--such as: my picture. jpg//filename=urlencoder.encode (filename, "utf-8");//to encode the filename, if not encoded, the browser will display the file name garbled
    InputStream In=downservlet.class.getclassloader (). getResourceAsStream (FileName); Protocol Settings 2 Resp.setheader ("Content-disposition", "attachment;filename=\" +filename+ "\");//Tell the browser the current download file name//downserv Let.class's Location: "D:\apache-tomcat-7.0.30\webapps\helloWeb\WEB-INF\classEs\cn\hncu\servlet "//Picture's current position:" D:\apache-tomcat-7.0.30\webapps\helloWeb\WEB-INF\classes "//fileinputstream fin=
    New FileInputStream (fileName);//Not OutputStream out=resp.getoutputstream ();
    byte buf[]=new byte[512];
int len=0; while ((Len=fin.read (BUF))!=-1) {//Out.write (buf, 0, Len);//} while ((Len=in.read (BUF)!=-1) {OUT.WR
    ITE (buf, 0, Len);
 }
  }


}

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