What is the java file stream interface and download method?

This article introduces the relevant knowledge of "what is the interface of java file stream and the method of downloading". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Java file stream interface

Package com.rainmanqqst.controller.filestream;import com.Ostermiller.util.Base64;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.* / * * @ author RAINMANQQST * @ date 2019-07-15 14:52 * @ description * / @ RestController@RequestMapping ("/ fille") public class FileController {private static Logger logger = LoggerFactory.getLogger (FileController.class) / * * convert the direct resource request interface address to the file stream interface * the file address encrypted by filePath for base64 * @ param filePath * @ param request * @ param response * / @ RequestMapping (value= "/ resource/ {filePath}") public void achieveResource (@ PathVariable ("filePath") String filePath, HttpServletRequest request, HttpServletResponse response) {try {String path = Base64.decode (filePath) Logger.info ("resource path is" + path); File file = new File (filePath); logger.info ("fileName:" + file.getName ()); response.setHeader ("Content-disposition", "attachment; filename=" + file.getName ()); response.setContentType ("application/octet-stream;charset=UTF-8") Response.setHeader ("Content-Length", file.length () + "); InputStream inputStream = new FileInputStream (file); ServletOutputStream servletOutputStream = response.getOutputStream (); int len= 0; byte [] buffer = new byte [1024]; while ((len=inputStream.read (buffer)) > 0) {servletOutputStream.write (buffer, 0, len) } servletOutputStream.flush (); inputStream.close (); servletOutputStream.close ();} catch (Exception ex) {ex.printStackTrace ();}

JS download code

Function exportFile () {/ / name= file name, blob= file binary object / / get timestamp var timestamp=new Date () .getTime (); / get XMLHttpRequest var xmlResquest = new XMLHttpRequest (); / / initiate request xmlResquest.open ("POST", "http://localhost:8086/rainmanqqst/api/system/resource/aHR0cHM6Ly9pbWcxLmRvdWJhbmlvLmNvbS92aWV3L3Bob3RvL2wvcHVibGljL3AxNDIyMDcxNjA4LndlYnA=", true)" / / set request header type xmlResquest.setRequestHeader ("Content-type", "application/json"); / / set request token / / xmlResquest.setRequestHeader (/ / "Authorization", / / Vue.cookie.get ('token') / /); xmlResquest.responseType = "blob" / return xmlResquest.onload = function (oEvent) {var content = xmlResquest.response; alert (content); / / assemble a tag var elink = document.createElement ("a"); / / set the download file name elink.download = timestamp + ".png" Elink.style.display = "none"; var blob = new Blob ([content]); elink.href = URL.createObjectURL (blob); document.body.appendChild (elink); elink.click (); document.body.removeChild (elink);}; xmlResquest.send ();}