The structure of the WebApp project is as follows:
The contents of the download.html file are as follows:
<! DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert Title here</title></head><body> <H1>Resources Download:</H1> <p>Simple use of a tag, only the browser can not parse the file will be downloaded, otherwise it will be directly resolved by the browser.</P> <a href="/web/resource/a.mp3" >A.mp3</a><br> <a href="/web/resource/a.exe" >A.exe</a><br> <a href="/web/resource/a.txt" >A.txt</a><br> <a href="/web/resource/a.xlsx" >A.xlsx</a><br> <a href="/web/resource/a.png" >A.png</a><br> <p>Therefore, using the a tag combined with the response of the servlet instructs the browser not to parse these pending files</P> <a href="/web/download?filename=a.mp3" >A.mp3</a><br> <a href="/web/download?filename=a.exe" >A.exe</a><br> <a href="/web/download?filename=a.txt" >A.txt</a><br> <a href="/web/download?filename=a.xlsx" >A.xlsx</a><br> <a href="/web/download?filename=a.png" >A.png</a><br></body></html>The contents of the Servlet--download.java file to be processed for download are as follows:
PackageCom.download.servlet;ImportJava.io.FileInputStream;ImportJava.io.IOException;ImportJava.io.InputStream;ImportJavax.servlet.ServletException;ImportJavax.servlet.ServletOutputStream;ImportJavax.servlet.http.HttpServlet;ImportJavax.servlet.http.HttpServletRequest;ImportJavax.servlet.http.HttpServletResponse;/** * Servlet Implementation class Download */ Public class Download extends httpservlet {Private Static Final LongSerialversionuid =1L; protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, IOException{//1. Get the file name of the request downloadString filename = Request.getparameter ("FileName");//2. Getting the file system path for a fileString FilePath = Request.getservletcontext (). Getrealpath ("resource/"+filename);//3. Set the response header to prompt the browser not to parse the response's file data, but instead to parse it in the form of an attachment (attachment), which is the download functionResponse.setcontenttype ( This. Getservletcontext (). GetMimeType (filename); Response.setheader ("Content-disposition","Attachment;filename="+filename);//4. Read the input stream of the file, as well as the output stream of the response, and output the data to the clientInputStream in =NewFileInputStream (FilePath); Servletoutputstream out = Response.getoutputstream ();intLen =0;byte[] buf =New byte[1024x768]; while((Len=in.read (BUF))!=-1) {Out.write (buf,0, Len); } in.close (); } protected void doPost(httpservletrequest request, httpservletresponse response) throws servletexception, IOException{doget (request, response); }}Enter it in the browser address bar http://localhost:8080/DownloadServlet/download.html .
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Java Web Response provides file download functionality
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