resolved

javax-servlets/src/main/java/com/baeldung/Constants.java

@@ -0,0 +1,11 @@
+package com.baeldung;
+
+public class Constants {
+
+  public static final String UPLOAD_DIRECTORY = "upload";
+  public static final String DEFAULT_FILENAME = "default.file";
+
+  public static final int MEMORY_THRESHOLD = 1024 * 1024 * 3;
+  public static final int MAX_FILE_SIZE = 1024 * 1024 * 40;
+  public static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50;
+}

javax-servlets/src/main/java/com/baeldung/servlets/MultipartServlet.java

@@ -0,0 +1,54 @@
+package com.baeldung.servlets;
+
+import com.baeldung.Constants;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.MultipartConfig;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.Part;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+import static com.baeldung.Constants.UPLOAD_DIRECTORY;
+
+@WebServlet(
+    name = "MultiPartServlet",
+    urlPatterns = {"/multiPartServlet"}
+)
+@MultipartConfig(fileSizeThreshold = 1024 * 1024, maxFileSize = 1024 * 1024 * 5, maxRequestSize = 1024 * 1024 * 5 * 5)
+public class MultipartServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    private String getFileName(Part part) {
+        for (String content : part.getHeader("content-disposition").split(";")) {
+            if (content.trim().startsWith("filename"))
+                return content.substring(content.indexOf("=") + 2, content.length() - 1);
+        }
+        return Constants.DEFAULT_FILENAME;
+    }
+
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY;
+        File uploadDir = new File(uploadPath);
+        if (!uploadDir.exists())
+            uploadDir.mkdir();
+
+        try {
+            String fileName = "";
+            for (Part part : request.getParts()) {
+                fileName = getFileName(part);
+                part.write(uploadPath + File.separator + fileName);
+            }
+            request.setAttribute("message", "File " + fileName + " has uploaded successfully!");
+        } catch (FileNotFoundException fne) {
+            request.setAttribute("message", "There was an error: " + fne.getMessage());
+        }
+        getServletContext().getRequestDispatcher("/result.jsp").forward(request, response);
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/UploadServlet.java

@@ -0,0 +1,63 @@
+package com.baeldung.servlets;
+
+import javax.servlet.annotation.WebServlet;
+import org.apache.commons.fileupload.FileItem;
+import org.apache.commons.fileupload.disk.DiskFileItemFactory;
+import org.apache.commons.fileupload.servlet.ServletFileUpload;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+import static com.baeldung.Constants.*;
+
+@WebServlet(
+    name = "UploadServlet",
+    urlPatterns = {"/uploadFile"}
+)
+public class UploadServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        if (ServletFileUpload.isMultipartContent(request)) {
+
+            DiskFileItemFactory factory = new DiskFileItemFactory();
+            factory.setSizeThreshold(MEMORY_THRESHOLD);
+            factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
+
+            ServletFileUpload upload = new ServletFileUpload(factory);
+            upload.setFileSizeMax(MAX_FILE_SIZE);
+            upload.setSizeMax(MAX_REQUEST_SIZE);
+            String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY;
+            File uploadDir = new File(uploadPath);
+            if (!uploadDir.exists()) {
+                uploadDir.mkdir();
+            }
+
+            try {
+                List<FileItem> formItems = upload.parseRequest(request);
+
+                if (formItems != null && formItems.size() > 0) {
+                    for (FileItem item : formItems) {
+                        if (!item.isFormField()) {
+                            String fileName = new File(item.getName()).getName();
+                            String filePath = uploadPath + File.separator + fileName;
+                            File storeFile = new File(filePath);
+                            item.write(storeFile);
+                            request.setAttribute("message", "File " + fileName + " has uploaded successfully!");
+                        }
+                    }
+                }
+            } catch (Exception ex) {
+                request.setAttribute("message", "There was an error: " + ex.getMessage());
+            }
+            getServletContext().getRequestDispatcher("/result.jsp").forward(request, response);
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/UploadWelcomeServlet.java

@@ -0,0 +1,18 @@
+package com.baeldung.servlets;
+
+import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name = "UploadWelcomeServlet", urlPatterns = "/uploadwelcome")
+public class UploadWelcomeServlet extends HttpServlet {
+
+  @Override
+  protected void doGet(HttpServletRequest request, HttpServletResponse response)
+      throws ServletException, IOException {
+    request.getRequestDispatcher("/upload.jsp").forward(request, response);
+  }
+}

javax-servlets/src/main/webapp/WEB-INF/web.xml

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
-         version="3.1">
-
-</web-app>

javax-servlets/src/main/webapp/result.jsp

@@ -0,0 +1,13 @@
+<%@ 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>
+
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <title>Upload Result</title>
+</head>
+
+<body>
+    <h2>${message}</h2>
+</body>
+</html>

javax-servlets/src/main/webapp/upload.jsp

@@ -0,0 +1,23 @@
+<%@ 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>
+
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <title>File Upload Demo</title>
+</head>
+
+<body>
+    <div>Apache FileUpload</div>
+    <form method="post" action="uploadFile" enctype="multipart/form-data">
+        Choose a file: <input type="file" name="uploadFile"/><input type="submit" value="Upload"/>
+    </form>
+
+    </br>
+
+    <div>Servlet Multipart</div>
+    <form method="post" action="multiPartServlet" enctype="multipart/form-data">
+        Choose a file: <input type="file" name="multiPartServlet"/><input type="submit" value="Upload"/>
+    </form>
+</body>
+</html>