Javaweb implementation of File download method and instance code _java

Javaweb implementation File Download

Do not use <a> tags to download, this will open the file rather than download

For example:

<a href= "E:\MyDesktop\37fecd65330184de67d419a8d02e7081.jpg" > Download </a>

If I write this, the browser will open the picture directly, unless it is a file that cannot be opened by a browser

So we still need to use the Java itself to read and write files to download the file

<a href= "Downloadfile?filename=<s:property value= ' document_filename '/>" > Download </a>

Package com.cpsec.tang.chemical.action;
Import Java.io.File;
Import Java.io.FileInputStream;
Import java.io.FileNotFoundException;
Import Java.io.FileOutputStream;
Import java.io.IOException;
Import Java.io.InputStream;
Import Java.io.OutputStream;
Import Java.text.SimpleDateFormat;
Import Java.util.Calendar;
Import java.util.List;

Import Java.util.Random;
Import Javax.annotation.Resource;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse;
Import Org.apache.struts2.ServletActionContext;
Import Org.springframework.stereotype.Controller;
Import Com.cpsec.tang.chemical.biz.DocumentBiz;
Import com.cpsec.tang.chemical.entity.Document;
Import Com.cpsec.tang.chemical.util.Pager;

Import Com.opensymphony.xwork2.ActionSupport;
  @Controller ("Documentaction") public class Documentaction extends actionsupport{private String filename;
    Public String DownloadFile () {System.out.println (filename); try {httpservletresponse Response=servletactIoncontext.getresponse (); 
      Sets the file MIME type Response.setcontenttype (Servletactioncontext.getservletcontext (). GetMimeType (filename)); 
      Set Content-disposition response.setheader ("Content-disposition", "attachment;filename=" +filename); 
      Gets the absolute path of the destination file String fullfilename = Servletactioncontext.getservletcontext (). Getrealpath ("/files/" + filename); 
      System.out.println (Fullfilename); 
      Read file InputStream in = new FileInputStream (fullfilename); 
      Read the target file and write the target file to the client outputstream out = Response.getoutputstream () by response; 
      Write file int b; 
      while ((B=in.read ())!=-1) {out.write (b); 
      } in.close (); 
    Out.close ();
    catch (Exception e) {e.printstacktrace ();
  return SUCCESS;

 }
  
}

Thank you for reading, I hope to help you, thank you for your support for this site!