UploadFile Servlet – Ejemplo

 

upload.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

    <title>UploadFile</title>
  </head>
<body>
	<p></p>
	<br></br>
    <center>
    <div class="jumbotron">
       <h1 class="display-4">UploadFile</h1>
        <p class="lead">Formulario para subir Documentos.</p>
        <hr class="my-4">
       <form method="post" action="uploadFile" enctype="multipart/form-data">
            Select file to upload:
            <input type="file" name="uploadFile" />
            <br/><br/>
            <input class="btn btn-primary" type="submit" value="Upload" />
        </form>
	</div>
    </center>
    <br><br>
</body>
</html>

message.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

    <title>UploadFile</title>
  </head>
<body>
	<p></p>
	<br></br>
	<center>
    <div class="jumbotron">
         <h1 class="display-4">${message}</h1>         
         <p></p>
         <a class="btn btn-primary btn-lg" href="/uploadfile/" role="button">Volver</a>
	</div>
    </center>
</body>
</html>

UploadFileServlet.java

package src.main.java.org.engineering.upload;


import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
 
/**
 * A Java servlet that handles file upload from client.
 *
 * @author www.codejava.net
 */
public class FileUploadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
     
    // location to store file uploaded
    private static final String UPLOAD_DIRECTORY = "upload";
 
    // upload settings
    private static final int MEMORY_THRESHOLD   = 1024 * 1024 * 3;  // 3MB
    private static final int MAX_FILE_SIZE      = 1024 * 1024 * 40; // 40MB
    private static final int MAX_REQUEST_SIZE   = 1024 * 1024 * 50; // 50MB
 
    /**
     * Upon receiving file upload submission, parses the request to read
     * upload data and saves the file on disk.
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // checks if the request actually contains upload file
        if (!ServletFileUpload.isMultipartContent(request)) {
            // if not, we stop here
            PrintWriter writer = response.getWriter();
            writer.println("Error: Form must has enctype=multipart/form-data.");
            writer.flush();
            return;
        }
 
        // configures upload settings
        DiskFileItemFactory factory = new DiskFileItemFactory();
        // sets memory threshold - beyond which files are stored in disk
        factory.setSizeThreshold(MEMORY_THRESHOLD);
        // sets temporary location to store files
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
 
        ServletFileUpload upload = new ServletFileUpload(factory);
         
        // sets maximum size of upload file
        upload.setFileSizeMax(MAX_FILE_SIZE);
         
        // sets maximum size of request (include file + form data)
        upload.setSizeMax(MAX_REQUEST_SIZE);
 
        // constructs the directory path to store upload file
        // this path is relative to application's directory
        String uploadPath = getServletContext().getRealPath("")
                + File.separator + UPLOAD_DIRECTORY;
         
        // creates the directory if it does not exist
        File uploadDir = new File(uploadPath);
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }
 
        try {
            // parses the request's content to extract file data
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);
 
            if (formItems != null && formItems.size() > 0) {
                // iterates over form's fields
                for (FileItem item : formItems) {
                    // processes only fields that are not form fields
                    if (!item.isFormField()) {
                        String fileName = new File(item.getName()).getName();
                        String filePath = uploadPath + File.separator + fileName;
                        File storeFile = new File(filePath);
 
                        // saves the file on disk
                        item.write(storeFile);
                        request.setAttribute("message",
                            "Upload has been done successfully!");
                    }
                }
            }
        } catch (Exception ex) {
            request.setAttribute("message",
                    "There was an error: " + ex.getMessage());
        }
        // redirects client to message page
        getServletContext().getRequestDispatcher("/message.jsp").forward(
                request, response);
    }
}

 

El proyecto se puede descargar desde :  https://gitlab.com/l30bravo/servlet_updaloadfile

Saludos