package com.hmkcode;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.LinkedList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.hmkcode.vo.FileMeta;
//this to be used with Java Servlet 3.0 API
@MultipartConfig
public class FileUploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
// this will store uploaded files
private static List<FileMeta> files = new LinkedList<FileMeta>();
/***************************************************
* URL: /upload
* doPost(): upload the files and other parameters
****************************************************/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException{
// 1. Upload File Using Java Servlet API
//files.addAll(MultipartRequestHandler.uploadByJavaServletAPI(request));
// 1. Upload File Using Apache FileUpload
files.addAll(MultipartRequestHandler.uploadByApacheFileUpload(request));
// Remove some files
while(files.size() > 20)
{
files.remove(0);
}
// 2. Set response type to json
response.setContentType("application/json");
// 3. Convert List<FileMeta> into JSON format
ObjectMapper mapper = new ObjectMapper();
// 4. Send resutl to client
mapper.writeValue(response.getOutputStream(), files);
}
/***************************************************
* URL: /upload?f=value
* doGet(): get file of index "f" from List<FileMeta> as an attachment
****************************************************/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException{
// 1. Get f from URL upload?f="?"
String value = request.getParameter("f");
// 2. Get the file of index "f" from the list "files"
FileMeta getFile = files.get(Integer.parseInt(value));
try {
// 3. Set the response content type = file content type
response.setContentType(getFile.getFileType());
// 4. Set header Content-disposition
response.setHeader("Content-disposition", "attachment; filename=\""+getFile.getFileName()+"\"");
// 5. Copy file inputstream to response outputstream
InputStream input = getFile.getContent();
OutputStream output = response.getOutputStream();
byte[] buffer = new byte[1024*10];
for (int length = 0; (length = input.read(buffer)) > 0;) {
output.write(buffer, 0, length);
}
output.close();
input.close();
}catch (IOException e) {
e.printStackTrace();
}
}
}