Export to zip file

1 to export to a ZIP file, you must first write the content to a file. Create the file and then write the content to the file. Writes content to a file through a stream.
such as: File File=new file (filename_);
FileOutputStream fileoutputstream=new fileoutputstream (file);
String neirong= "This is the content of the test";
Byte_s=neirong.getbytes ();
Fileoutputstream.write (byte_s,0,byte_s.length);//This is the writing of byte data to a file via a stream.
Fileoutputstream.close ();


2 Next you want to export to a zip file, you need to create a zip format file. Write the contents to the zip file at the same time.
such as: File Zipfile=new file ("complete" +new Date (). GetTime () + ". zip");
FileOutputStream zipout;
The above is a file that will create a zip format


ZipOut = new FileOutputStream (ZipFile);
Zipoutputstream zip=new Zipoutputstream (zipout);

ZipEntry zipentry1=new zipentry ("Aaa.txt");
Zip.putnextentry (ZipEntry1);
byte [] byte_s= "test content AAA". GetBytes ();
Zip.write (byte_s,0,byte_s.length);

Zip.close ();
Zipout.close ();
Writes content to a file in a zip format via zipoutputstream. If you want to add any files during the period. Add by ZipEntry.
A zipentry represents a file or a folder.


3 Zipoutputstream is a file that writes a stream to a zip format. ZipEntry is a sub-unit in a zip format file. can represent a file or folder.
If adding a file:
File Zipfile=new file ("complete" +new Date (). GetTime () + ". zip");
FileOutputStream zipout;
The above is a file that will create a zip format


ZipOut = new FileOutputStream (ZipFile);
Zipoutputstream zip=new Zipoutputstream (zipout);

ZipEntry zipentry1=new zipentry ("Aaa.txt");
Zip.putnextentry (ZipEntry1);
byte [] byte_s= "test content AAA". GetBytes ();
Zip.write (byte_s,0,byte_s.length);

Zip.close ();
Zipout.close ();


If you are adding a folder:
File Zipfile=new file ("complete" +new Date (). GetTime () + ". zip");
FileOutputStream zipout;
The above is a file that will create a zip format


ZipOut = new FileOutputStream (ZipFile);
Zipoutputstream zip=new Zipoutputstream (zipout);

ZipEntry zipentry1=new ZipEntry (Name of folder + "/");//Name of folder Plus "/"
Zip.putnextentry (ZipEntry1);
byte [] byte_s= "test content AAA". GetBytes ();
Zip.write (byte_s,0,byte_s.length);

Zip.close ();
Zipout.close ();


ZipEntry and Zipoutputstream are inseparable.


4 Now if the ZIP format of the file has been created, then it is necessary to read the zip file. Gets the byte array. It's like reading a normal file.
such as: Bytearrayoutputstream byteout=new bytearrayoutputstream ();
FileInputStream fileInput = new FileInputStream (ZipFile);

byte [] byte_i=new byte[1024];
int num_i=0;
while ((Num_i= (Fileinput.read (byte_i))) >-1) {
Byteout.write (byte_i,0,num_i);
}
byte [] Byte_z=byteout.tobytearray ();

Fileinput.close ();
Byteout.close ();


5 A byte array is obtained after reading the file in zip format. Can be written by response. This is where you set some parameters.
such as: Resp.setcontenttype ("Application/zip");
Resp.setheader ("Content-disposition", "Attachment;filename=" +zipfile.getname () + "");
OutputStream FileOutputStream = Resp.getoutputstream ();
Fileoutputstream.write (byte_z);
Fileoutputstream.flush ();
Fileoutputstream.close ();
This gives you the ability to get a file in zip format. On the foreground screen. But remember. is directly called through the response of the foreground.


6 The method that calls the background directly in the foreground page. Written by JSP syntax. Like the export.jsp.
such as: <%@ page language= "java" import= "java.util.*" pageencoding= "UTF-8"%>
<%
New Com.service.DemoService (). Exportservice (Request,response);
%>


In this case, you need to invoke the JSP file to be exported in a JSP in the JS method.
such as: var Infowindow = window.open ("export.jsp", "_blank", "width=500,height=400");




A complete example. As follows:
Front Desk JS Method:
function Export_onclick () {
var Infowindow = window.open ("export.jsp", "_blank", "width=500,height=400");
}


export.jsp file:
<%@ page language= "java" import= "java.util.*" pageencoding= "UTF-8"%>
<%
New Com.service.DemoService (). Exportservice (Request,response);
%>




Exportservice methods for the Demoservice class:
public void Exportservice (HttpServletRequest req,httpservletresponse resp) {


File Zipfile=new file ("complete" +new Date (). GetTime () + ". zip");
System.out.println ("Location:" +zipfile.getabsolutepath ());
FileOutputStream zipout;
try {
ZipOut = new FileOutputStream (ZipFile);
Zipoutputstream zip=new Zipoutputstream (zipout);

ZipEntry zipentry1=new zipentry ("Aaa.txt");
Zip.putnextentry (ZipEntry1);
byte [] byte_s= "test content AAA". GetBytes ();
Zip.write (byte_s,0,byte_s.length);

Zip.close ();
Zipout.close ();

Bytearrayoutputstream byteout=new Bytearrayoutputstream ();
FileInputStream fileInput = new FileInputStream (ZipFile);

byte [] byte_i=new byte[1024];
int num_i=0;
while ((Num_i= (Fileinput.read (byte_i))) >-1) {
Byteout.write (byte_i,0,num_i);
}
byte [] Byte_z=byteout.tobytearray ();

Fileinput.close ();
Byteout.close ();
Application/x-zip-compressed
Resp.setcontenttype ("Application/zip");
Resp.setcontenttype ("application/x-zip-compressed");
Resp.setheader ("Content-disposition", "Attachment;filename=" +zipfile.getname () + "");
Resp.setheader ("Content-disposition", "Attachment;filename=" +zipfile.getname () + "");
Resp.setheader ("Location", Zipfile.getname ());
Resp.setheader ("Content-disposition", "Attachment;filename="
+ Zipfile.getname ());


OutputStream FileOutputStream = Resp.getoutputstream ();
Fileoutputstream.write (byte_z);
Fileoutputstream.flush ();
Fileoutputstream.close ();
return null;

} catch (Exception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}



}


Must be the foreground method that invokes the background directly through JSP syntax. The parameter is response. To remember.