我正在我的本地主机上创建一个简单的 Web 应用程序。我有一个像这样的表格:
<form method="post" enctype="multipart/form-data" action="UploadFile">
File:
<input type="file" name="file" id="file" />
Submit Button:
<input type="submit" value="upload"/>
</form>
不是我的确切形式，但你明白了。 UploadFile(即action =“UploadFile”)是一个Servlet。现在我知道我想要将文件上传到的路径。为了论证起见，假设路径如下:
String path = "Project\\web\\files\\";
//I want the file to be put into this folder.
那么我该如何处理将当前桌面上的文件上传到我刚刚编写的路径。
我使用Java已经有一段时间了，但以前从未做过文件上传。我在网上查看了一些解决方案，与使用其他编程语言处理文件上传的简单相比，这些解决方案似乎非常复杂。
上传此文件的最佳方式是什么。
最佳答案
添加以下 jar 文件
commons-collections-3.1.jar
commons-fileupload-1.2.2.jar
commons-io-2.1.jar
commons-logging-1.0.4.jar
Jsp页面
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>File Upload</title>
</head>
<body>
<form method="post" action="UploadServlet" enctype="multipart/form-data">
Select file to upload:
<input type="file" name="file" id="file"/><br/><br/>
<input type="submit" value="Upload" />
</form>
</body>
</html>
servlet 代码
package com.servlet;
import java.io.File;
import java.io.IOException;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String DATA_DIRECTORY = "data";
private static final int MAX_MEMORY_SIZE = 1024 * 1024 * 2;
private static final int MAX_REQUEST_SIZE = 1024 * 1024;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Check that we have a file upload request
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (!isMultipart) {
return;
}
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// Sets the size threshold beyond which files are written directly to
// disk.
factory.setSizeThreshold(MAX_MEMORY_SIZE);
// Sets the directory used to temporarily store files that are larger
// than the configured size threshold. We use temporary directory for
// java
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
// constructs the folder where uploaded file will be stored
String uploadFolder = getServletContext().getRealPath("")
+ File.separator + DATA_DIRECTORY;
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// Set overall request size constraint
upload.setSizeMax(MAX_REQUEST_SIZE);
try {
// Parse the request
List items = upload.parseRequest(request);
Iterator iter = items.iterator();
while (iter.hasNext()) {
FileItem item = (FileItem) iter.next();
if (!item.isFormField()) {
String fileName = new File(item.getName()).getName();
String filePath = uploadFolder + File.separator + fileName;
File uploadedFile = new File(filePath);
System.out.println(filePath);
// saves the file to upload directory
item.write(uploadedFile);
}
}
// displays done.jsp page after upload finished
getServletContext().getRequestDispatcher("/done.jsp").forward(
request, response);
} catch (FileUploadException ex) {
throw new ServletException(ex);
} catch (Exception ex) {
throw new ServletException(ex);
}
}
}
你的 web.xml 应该是这样的
<servlet>
<description></description>
<display-name>UploadServlet</display-name>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>com.servlet.UploadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/UploadServlet</url-pattern>
</servlet-mapping>
关于java - 如何使用 JSP 和 Servlet 在 Java 中上传文件？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40924453/