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说明:

  1. 使用commons-fileupload.jar实现文件上传及进度监听

  2. 使用bootstrap的进度条进行页面显示

  3. 因为进度数据保存在session中,所以同一个浏览器同时只能发送一次上传请求,多次发送进度会错乱

实例:

1.项目结构

2.pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>org.file</groupId>
<artifactId>process</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version> <dependencies>
<!-- Junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- Servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- Commons-fileupload -->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.2</version>
</dependency>
</dependencies> <build>
<finalName>process</finalName>
</build> </project>

3.index.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">
<title>Excel上传</title>
<link rel="stylesheet" type="text/css" href="bootstrap/bootstrap.min.css">
</head>
<body>
<div class="container" align="center">
<form action="uploadExcel" method="post" enctype="multipart/form-data">
<table class="table" style="width: 50%">
<tr id="msg" style="display: none;">
<th colspan="2" style="text-align: center;">
<font color="#00CD00">文件上传成功,共用时${time }ms</font>
</th>
</tr>
<tr>
<th>上传文件1:</th>
<td><input type="file" name="file"/></td>
</tr>
<tr>
<th>上传文件2:</th>
<td><input type="file" name="file"/></td>
</tr>
<tr>
<th>上传人:</th>
<td><input type="text" name="user"/></td>
</tr>
<tr>
<th> </th>
<td>
<button id="submit" type="submit" class="btn btn-default">上传</button>
</td>
</tr>
</table>
</form>
</div>
<!-- 文件上传模态框 -->
<div id="progressModal" class="modal fade" tabindex="-1" role="dialog" data-backdrop="static"
data-keyboard="false">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h4 class="modal-title">文件上传进度</h4>
</div>
<div class="modal-body">
<div id="progress" class="progress">
<div id="progress_rate" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"
class="progress-bar progress-bar-success progress-bar-striped active"
role="progressbar" style="width: 0%">
<span id="percent">0%</span>
</div>
</div>
</div>
</div>
</div>
</div>
<script type="text/javascript" src="bootstrap/jquery-3.2.0.min.js"></script>
<script type="text/javascript" src="bootstrap/bootstrap.min.js"></script>
<script type="text/javascript"> var process;// 定时对象 $(function() { var time = "${time}";
if (time != null && time != "") {
$("#msg").css("display", "block");
} $("#submit").bind("click", function(){ process = setInterval("getProcess()", 100);// 每0.1s读取一次进度
$("#progressModal").modal("show");// 打开模态框 }); }); // 读取文件上传进度并通过进度条展示
function getProcess() { $.ajax({
type: "get",
url: "uploadExcel",
success: function(data) {
var rate = data * 100;
rate = rate.toFixed(2);
$("#progress_rate").css("width", rate + "%");
$("#percent").text(rate + "%");
if (rate >= 100) {
clearInterval(process);
$("#percent").text("文件上传成功!");
}
}
}); } </script>
</body>
</html>

4.UploadProcess.java

package org.file.upload;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.Calendar;
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 javax.servlet.http.HttpSession; import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload; @WebServlet("/uploadExcel")
public class UploadProcess extends HttpServlet { private static final long serialVersionUID = 1L; @Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { System.out.println("开始上传文件..."); // 使用session保存进度数据
final HttpSession session = req.getSession(); long start_time = Calendar.getInstance().getTimeInMillis();
// 获取上传文件临时保存路径
String tempPath = this.getServletContext().getRealPath("/WEB-INF/upload"); File file = new File(tempPath);
if (!file.exists() && !file.isDirectory()) {// 目录不存在或不是一个目录
file.mkdirs();
} try {
// 创建DiskFileItemFactory工厂类
DiskFileItemFactory factory = new DiskFileItemFactory(); // 创建一个文件上传解析器
ServletFileUpload upload = new ServletFileUpload(factory);
// 监听文件上传进度
upload.setProgressListener(new ProgressListener() { public void update(long pBytesRead, long pContentLength, int pItems) { session.setAttribute("fileSize", pContentLength);
session.setAttribute("loadSize", pBytesRead); }
});
// 解决上传文件的中文乱码
upload.setHeaderEncoding("UTF-8"); if (!ServletFileUpload.isMultipartContent(req)) {// 普通表单
return ;
} else {
// 利用文件上传解析器解析数据并存放到list中
List<FileItem> list = upload.parseRequest(req);
// 循环所有数据
for (FileItem item: list) {
// 判断数据来源
if (item.isFormField()) {//普通输入框中的数据
String name = item.getFieldName();// 输入框的name值
String value = item.getString("UTF-8"); // 输入框的值
System.out.println(name + " : " + value);
} else {//文件
// 获取上传文件的文件路径(不同浏览器不同,有的是文件名,有的是全路径)
String fileName = item.getName();
if (fileName == null || "".equals(fileName.trim())) {
continue;
}
// 获取文件名
fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
// 获取上传文件的输入流
InputStream is = item.getInputStream();
// 创建一个文件输出流
FileOutputStream fos = new FileOutputStream(tempPath + "\\" + fileName);
// 创建一个缓存区
byte[] buff = new byte[1024]; int len = 0;
while ((len = is.read(buff)) > 0) {// 循环读取数据
fos.write(buff, 0, len);// 使用文件输出流将缓存区的数据写入到指定的目录中
}
// 关闭输出流
fos.close();
// 关闭输入流
is.close();
// 删除临时文件
item.delete();
}
}
}
long end_time = Calendar.getInstance().getTimeInMillis();
long lt = end_time - start_time;
System.out.println("文件上传成功,共用时" + (end_time - start_time) + "ms");
req.setAttribute("time", lt);
req.getRequestDispatcher("index.jsp").forward(req, resp);
} catch (Exception e) {
e.printStackTrace();
} } @Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 获取进度数据
HttpSession session = req.getSession();
Object obj1 = session.getAttribute("loadSize");
long loadSize = 0L;
if (obj1 != null) {
loadSize = Long.valueOf(obj1.toString());
}
Object obj2 = session.getAttribute("fileSize");
long fileSize = 1L;
if (obj2 != null) {
fileSize = Long.valueOf(obj2.toString());
} // 计算上传比例
double rate = loadSize * 1.0 / fileSize;
BigDecimal bd = new BigDecimal(rate);
rate = bd.setScale(4, BigDecimal.ROUND_HALF_UP).doubleValue(); // 返回
resp.setContentType("text/html;charset=UTF-8");
PrintWriter pw = resp.getWriter();
pw.write(rate + "");
pw.flush();
pw.close(); } }

5.效果预览