我目前正在开发一个动态Web应用程序，我希望用户能够一次上传多个文件以供应用程序使用。我不知道用户可以一次上传多少文件;它可能是2或它可能100多个文件。我是JSP动态Web应用程序的新手，我已经开始使用单个上传文件，但我不确定从哪里开始。我看过几个搜索的例子但是我找不到我想要的东西。这就是我到目前为止所做的：
的Servlet
package Servlets;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
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.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class UploadServlet extends HttpServlet
{
private static final long serialVersionUID = 1L;
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
if (isMultipart)
{
// Create a factory for disk-based file items
FileItemFactory factory = new DiskFileItemFactory();
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
try
{
// Parse the request
List items = upload.parseRequest(request);
Iterator iterator = items.iterator();
while (iterator.hasNext())
{
FileItem item = (FileItem) iterator.next();
if (!item.isFormField())
{
String fileName = item.getName();
String root = getServletContext().getRealPath("/");
File path = new File(root + "/uploads");
if (!path.exists())
{
boolean status = path.mkdirs();
}
File uploadedFile = new File(path + "/" + fileName);
System.out.println(uploadedFile.getAbsolutePath());
if(fileName!="")
item.write(uploadedFile);
else
out.println("file not found");
out.println("<h1>File Uploaded Successfully....:-)</h1>");
}
else
{
String abc = item.getString();
out.println("<br><br><h1>"+abc+"</h1><br><br>");
}
}
}
catch (FileUploadException e)
{
out.println(e);
}
catch (Exception e)
{
out.println(e);
}
}
else
{
out.println("Not Multipart");
}
}
}
.JSP文件：
<form method="post" action="UploadServlet" enctype="multipart/form-data">
Select file to upload:
<p><input type="file" name="dataFile" id="fileChooser" />
<input type="submit" value="Upload" multiple="multiple" /></p>
</form>
我正在寻找一种方法来上传多个文件，而不只是一个文件，并在列表中显示。
答案 0 :(得分：3)
检查 FileUPload Using Servlet 3.0
它有一个使用Servlet3.0上传单个文件的工作代码正如您所看到的，现在代码已经大大简化了。并且不依赖于apache库。
只需使用以下index.html
<html>
<head></head>
<body>
<form action="FileUploadServlet" method="post" enctype="multipart/form-data">
Select File to Upload:<input type="file" name="fileName" multiple="multiple"/>
<br>
<input type="submit" value="Upload"/>
</form>
</body>
</html>
此处仅更改是我已将multiple="multiple"属性用于输入类型File
答案 1 :(得分：1)
multiple是文件输入的属性，而不是提交按钮的属性。
答案 2 :(得分：1)
我使用jsp / servlet上传了多个文件。 以下是我使用的代码。
<form action="UploadFileServlet" method="post">
<input type="text" name="description" />
<input type="file" name="file" />
<input type="submit" />
</form>
。使用以下代码。
package com.abc..servlet;
import java.io.File;
---------
--------
/**
* Servlet implementation class UploadFileServlet
*/
public class UploadFileServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public UploadFileServlet() {
super();
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.sendRedirect("../jsp/ErrorPage.jsp");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter out = response.getWriter();
HttpSession httpSession = request.getSession();
String filePathUpload = (String) httpSession.getAttribute("path")!=null ? httpSession.getAttribute("path").toString() : "" ;
String path1 = filePathUpload;
String filename = null;
File path = null;
FileItem item=null;
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (isMultipart) {
FileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
String FieldName = "";
try {
List items = upload.parseRequest(request);
Iterator iterator = items.iterator();
while (iterator.hasNext()) {
item = (FileItem) iterator.next();
if (fieldname.equals("description")) {
description = item.getString();
}
}
if (!item.isFormField()) {
filename = item.getName();
path = new File(path1 + File.separator);
if (!path.exists()) {
boolean status = path.mkdirs();
}
/* START OF CODE FRO PRIVILEDGE*/
File uploadedFile = new File(path + Filename); // for copy file
item.write(uploadedFile);
}
} else {
f1 = item.getName();
}
} // END OF WHILE
response.sendRedirect("welcome.jsp");
} catch (FileUploadException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
答案 3 :(得分：0)
images.jsp
选择文件：storeimages.java servlet
public class storeimages extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException {
String sav_dir=""; //this will be a folder inside
//directory
PrintWriter out =response.getWriter();
//if you want u can give this at run time
sav_dir="6022"; //in my case folder name is 6022
//you can alse set this at dynamic
int flag = 0;
//now set the path
//this is the path where my images are stored
//now u can see the code
String savepath="K:/imageupload"+File.separator +sav_dir;
File file = new File(savepath);
if(!file.exists()){
file.mkdir();
}
String filename="";
List<Part> fileParts = request.getParts().stream().
filter(part->"file".equals(part.getName())).collect(Collectors.
toList());
for(Part filePart: fileParts){
filename=Paths.get(filePart.getSubmittedFileName()).
getFileName().toString();
filePart.write(savepath+File.separator+filename);
flag=1;
}
if(flag==1){
out.println("success");
}
else{
out.println("try again");
}
//now save this and run the project
}
}
答案 4 :(得分：0)
你只需要编写 multiple ，因为multiple是一个布尔变量而且只定义它，它对你的标记是真的。示例如下：
<input type="file" name="file" id="file" multiple/>
这将允许您一次选择多个文件。祝你好运
答案 5 :(得分：0)
这就是我的做法。它将动态添加和删除字段（多个文件）。对其进行验证，并在验证时调用操作方法，即servlet并存储在数据库中。 ** html / jsp ** .jsp文件
%F{1}jquery验证
%F{#ff0000}servlet
<div class="recent-work-pic">
<form id="upload_form" method="post" action="uploadFile" enctype="multipart/form-data" >
<input type="hidden" id="counter" value="1" >
<a href="javascript:void(0);" class="remove_fields" id="add_fields">Add</a>
<div class="record"><input type="file" placeholder="Upload File" name="uploadFile_0" class="upload_input"></div>
<div id="add_field_div"></div>
<button type="submit" class="btn btn-read">Submit</button>
</form>
<p>${message}</p>
</div>
我希望人们觉得它有用！！
答案 6 :(得分：-1)
要上传单个文件，您应该使用属性类型=“file”的单个标记。要允许多个文件上载，请包含多个具有不同name属性值的输入标记。浏览器将“浏览”按钮与每个按钮相关联。
即，多次使用以下行：
<input type="file" name="dataFile" id="fileChooser" /><br><br>
我希望这会有所帮助。