java上传文件

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上传文件

可参考：https://mp.weixin.qq.com/s?__biz=Mzg2NTAzMTExNg==&mid=2247484026&idx=1&sn=eba24b51963e8c3293d023cbcf3318dc&scene=19#wechat_redirect

java

package com.exam;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class UploadPage
 */

public class UploadPage extends HttpServlet {
	private static final long serialVersionUID = 1L;

	// 上传文件存储目录
	private static final String UPLOAD_DIRECTORY = "upload";

	// 上传配置
	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

	ServletContext servletContext = null;
	/**
	 * @see Servlet#init(ServletConfig)
	 */
	public void init(ServletConfig config) throws ServletException {
		// TODO Auto-generated method stub
		servletContext = config.getServletContext();
	}

	/**
	 * @see Servlet#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}

	/**
	 * @see HttpServlet#service(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		// 检测是否为多媒体上传
		if (!ServletFileUpload.isMultipartContent(request)) {
			// 如果不是则停止
			PrintWriter writer = response.getWriter();
			writer.println("Error: 表单必须包含 enctype=multipart/form-data");
			writer.flush();
			return;
		}

		// 配置上传参数
		DiskFileItemFactory factory = new DiskFileItemFactory();
		// 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中
		factory.setSizeThreshold(MEMORY_THRESHOLD);
		// 设置临时存储目录
		factory.setRepository(new File(System.getProperty("java.io.tmpdir")));

		ServletFileUpload upload = new ServletFileUpload(factory);

		// 设置最大文件上传值
		upload.setFileSizeMax(MAX_FILE_SIZE);

		// 设置最大请求值 (包含文件和表单数据)
		upload.setSizeMax(MAX_REQUEST_SIZE);

		// 中文处理
		upload.setHeaderEncoding("UTF-8");

		// 构造临时路径来存储上传的文件
		// 这个路径相对当前应用的目录
		String uploadPath = servletContext.getRealPath("/WEB-INF/") + File.separator + UPLOAD_DIRECTORY;

		// 如果目录不存在则创建
		File uploadDir = new File(uploadPath);
		if (!uploadDir.exists()) {
			uploadDir.mkdir();
		}

		try {
			// 解析请求的内容提取文件数据
			@SuppressWarnings("unchecked")
			List<FileItem> formItems = upload.parseRequest(request);

			if (formItems != null && formItems.size() > 0) {
				// 迭代表单数据
				for (FileItem item : formItems) {
					// 处理不在表单中的字段
					if (!item.isFormField()) {
						String fileName = new File(item.getName()).getName();
						String filePath = uploadPath + File.separator + fileName;
						File storeFile = new File(filePath);
						// 在控制台输出文件的上传路径
						System.out.println(filePath);
						// 保存文件到硬盘
						item.write(storeFile);
						request.setAttribute("message", "文件"+filePath+"上传成功!");
					}
				}
			}
		} catch (Exception ex) {
			request.setAttribute("message", "错误信息: " + ex.getMessage());
		}
		// 跳转到 message.jsp
		servletContext.getRequestDispatcher("/message.jsp").forward(request, response);
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

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>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="css/upload.css">
<title>upload</title>
</head>
<body>

	<div id="wrap">
		<h1>UPLOAD A FILE</h1>
		<br><br><br>
		<div id="form-wrap">
			<form method="post" action="/examination/UploadPage"
		enctype="multipart/form-data">
				<p>HELLO</p>
				<label for="email">Choose A File</label>
				<textarea name="message" id="message" value="Your Message"></textarea>
				<p>Move here ,</p>
				<label for="name">File Name</label>
				<input type="file" name="uploadFile" />
				
				<label for="email" style="margin-left: -60px">Replace Name:</label>
				<input type="text" name="replacename" value="" id="email" />
				
				<input type="submit" name="submit" value="NOW, UPLOAD YOUR FILE!" />
			</form>
		</div>
	</div>
</body>
</html>

css

@CHARSET "UTF-8";
body, div, h1, h2, form, fieldset, input, textarea, footer, p{
	margin: 0;
	padding: 0;
	border: 0;
	outline: none;
}
body{
	background: pink;
	color: gray;
	font-family: tahoma;
}
p{
	font-family: tahoma;
	font-size: 24px;
	color: #757575;
}
#wrap{
	width: 530px;
	margin: 20px auto 0;
	height: 1000px;
}
h1{
	margin-bottom: 20px;
	text-align: center;
	font-size: 35px;
	font-family: tahoma;
	color: black;
}
#form-wrap{
	overflow: hidden;
	height: 447px;
	position: relative;
	top: 0px;
	transition: all 1s ease-in-out .3s;
}
#form-wrap:before{
	content: "";
	position: absolute;
	bottom: 128px;
	left: 0px;
	background: url('../img/before.png');
	width: 530px;
	height: 317px;
}
#form-wrap:after{
	content: "";
	position: absolute;
	bottom: 0px;
	left: 0;
	background: url('../img/after.png');
	width: 530px;
	height: 259px;
}
#form-wrap.hide:after,
#form-wrap.hide:before{
	display: none;
}
#form-wrap:hover{
	height: 777px;
	top: -200px;
}
form{
	background: url('../img/letter_bg.png');
	position: relative;
	top: 200px;
	overflow: hidden;
	height: 200px;
	width: 400px;
	margin: 0px auto;
	padding: 20px;
	border: 1px solid white;
	border-right: 3px;
	transition: all 1s ease-in-out .3s;
}
#form-wrap:hover form{
	height: 530px;
}
lable{
	margin: 11px 20px 0 0;
	font-size: 15px;
	color: gray;
	text-transform: uppercase;
}
input[type=text], textarea{
	font: 14px normal uppercase, arial, serif;
	color: dimgray;
	background: none;
	width: 380px;
	height: 37px;
	padding: 0px 10px;
	margin: 0 0 10px 0;
	border: 1px solid #BDBDBD;
	border-radius: 5px;
}
textarea{
	height: 80px;
	padding-top: 14px;
}
textarea:focus,
input[type=text]:focus{
	background: url('../img/letter_bg.png');
}
#form-wrap input[type=submit]{
	position: relative;
	font-family: tahoma;
	font-size: 24px;
	color: gray;
	width: 300px;
	text-align: center;
	opacity: 0;
	background: none;
	cursor: pointer;
	border-radius: 3px;
	transition: opacity 0.7s ease-in-out 0s;
}
#form-wrap:hover input[type=submit]{
	z-index: 1;
	opacity: 1;
	transition: opacity 0.5s ease-in-out 1.3s;
}