现在文件的上传，特别是大文件上传，都需要进度条，让客户知道上传进度。
本文简单记录下如何弄进度条，以及一些上传信息，比如文件的大小，上传速度，预计剩余时间等一些相关信息。代码是匆忙下简单写的，一些验证没做，或代码存在一些隐患，不严谨的地方。本文代码只供参考。
进度条的样式多种多样，有些网站弄得非常绚烂漂亮。本文UI端不太懂，只会一些简单的基本的css而已，所以进度条弄得不好看。本文侧重的给读者提供一个参考，一个实现思路而已。
注：由于jQuery版本用的是2.1.1,所以如果跑本例子源码，请用IE9以上或火狐、谷歌浏览器测试。
接收文件上传的servlet
UploadFileServlet.Java
package com.fei.servlet;
import java.io.IOException;
import java.util.Date;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.fei.util.FileUploadUtil;
public class UploadFileServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
long start = System.currentTimeMillis();
System.out.println("开始上传文件........." );
Map<String, String> params = FileUploadUtil.upload(request);
System.out.println("文件上传完成........." );
System.out.println("文件上次用时:"+(System.currentTimeMillis()-start)+"毫秒");
} catch (Exception e) {
e.printStackTrace();
}
}
}
将上传文件进行下载到服务器的处理
FileUploadUtil.java
package com.fei.util;
import java.io.File;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
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;
public class FileUploadUtil {
/**
* 文件上传保存路径
*/
private static final String SAVE_FILEPATH = "/fileupload/";
/**
* 文件上传临时保存路径
*/
private static final String SAVE_FILE_TMPPATH = "/fileupload/tmp/";
/**
* 上传文件的最大值M
*/
private static final int MAX_FILE_SIZE = 100*1024*1024;
/**
* 文件数据在内存中超过多少M后，就写入临时文件
*/
private static final int THRESHOLD_SIZE = 2*1024*1024;
private static final String ENCODING = "UTF-8";
/**
* 处理文件上传的表单
* 下载文件，并返回文件名称及普通表单域中其它属性值
* 获取文件名
*/
public static Map<String,String> upload(HttpServletRequest request)throws Exception{
Map<String,String> params = new HashMap<String, String>();
String savePath = request.getSession().getServletContext()
.getRealPath(SAVE_FILEPATH)+ File.separator;
String savePathTemp = request.getSession().getServletContext()
.getRealPath(SAVE_FILE_TMPPATH)+ File.separator;
File saveFileTempDir = new File(savePathTemp);
DiskFileItemFactory factory = new DiskFileItemFactory();
//当内存中文件数据达到THRESHOLD_SIZE后，就写入临时文件中，避免上传大文件时，消化太多内存
factory.setSizeThreshold(THRESHOLD_SIZE);
factory.setRepository(saveFileTempDir);
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding(ENCODING);
upload.setSizeMax(MAX_FILE_SIZE);
FileUploadInfo fileUploadInfo = new FileUploadInfo();
upload.setProgressListener(new FileUploadListener(fileUploadInfo));
request.getSession().setAttribute("uploadInfo", fileUploadInfo);
List items = upload.parseRequest(request);
Iterator iter = items.iterator();
int fileNum = 1;
while(iter.hasNext()){
FileItem item = (FileItem) iter.next();
if (item.isFormField()) {//普通表单域
params.put(item.getFieldName(), item.getString());
} else {
String fileName = item.getName().replace("/", "\\");
int i = fileName.lastIndexOf("\\");
fileName = fileName.substring(i+1);
//避免重复
fileName = System.currentTimeMillis() + fileName;
File uploadedFile = new File(savePath + fileName);
item.write(uploadedFile);
params.put("fileName0"+fileNum, fileName);
fileNum ++;
}
}
return params;
}
}
class FileUploadListener implements ProgressListener{
FileUploadInfo fileUploadInfo = null;
public FileUploadListener(FileUploadInfo fileUploadInfo) {
this.fileUploadInfo = fileUploadInfo;
}
@Override
public void update(long uploadSize, long totalSize, int itemNum) {
this.fileUploadInfo.setTotalSize(totalSize);
this.fileUploadInfo.setUploadSize(uploadSize);
}
}
上传文件的一些信息
FileUploadInfo.java
package com.fei.util;
public class FileUploadInfo {
private final int K = 1024;
private final int M = K * 1024;
/**
* 总大小
*/
private long totalSize;
/**
* 开始上传时间
*/
private long startTime = System.currentTimeMillis();
/**
* 已上传多少
*/
private long uploadSize;
/**
* 上传速度(K/S)
*/
public double getUploadSpeed_K(){
long currentTime = System.currentTimeMillis();
long usedTime = currentTime - startTime;
if(usedTime == 0.0){
return 0.0;
}
return getUploadSize_K()/usedTime*1000d;
}
/**
* 获取已上传百分比
* @return
*/
public double getUploadPercent(){
return (getUploadSize()*1.00/getTotalSize())*100d;
}
/**
* 剩余时间(s)
* @return
*/
public double getRemainTime(){
double speedKB = getUploadSpeed_K();
if(speedKB<= 0.00){
return -1d;
}
return (getTotalSize_K() - getUploadSize_K())/speedKB;
}
/**
* 已上传时间
* @return
*/
public double getUseTime(){
return (System.currentTimeMillis() - startTime)/1000d;
}
public long getTotalSize() {
return totalSize;
}
public double getTotalSize_K(){
return getTotalSize()*1.0/K;
}
public double getTotalSize_M(){
return getTotalSize()*1.0/M;
}
public long getUploadSize() {
return uploadSize;
}
public double getUploadSize_K(){
return getUploadSize()/K;
}
public double getUploadSize_M(){
return getUploadSize()/M;
}
public void setTotalSize(long totalSize) {
this.totalSize = totalSize;
}
public void setUploadSize(long uploadSize) {
this.uploadSize = uploadSize;
}
private String double2String(double d){
return String.format("%.2f", d);
}
public String toString(){
return "{"+
"'totalSize':'"+double2String(getTotalSize_M())+"M',"+
"'uploadSize':'"+double2String(getUploadSize_M())+"M',"+
"'uploadSpeed':'"+double2String(getUploadSpeed_K())+"KB/s',"+
"'uploadPrecent':'"+double2String(getUploadPercent())+"',"+
"'remainTime':'"+(getRemainTime()<0"未知":double2String(getRemainTime()))+"s"+"',"+
"'useTime':'"+double2String(getUseTime())+"s' "+
"}";
}
}
读取文件上传进度的servlet
UploadFileProgressServlet.java
package com.fei.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.fei.util.FileUploadInfo;
public class UploadFileProgressServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String responseContent = "";
Object obj = request.getSession().getAttribute("uploadInfo");
if(obj == null){
responseContent = "{'data':'NoData'}";
}else{
FileUploadInfo uploadInfo = (FileUploadInfo)obj;
responseContent = uploadInfo.toString();
if(uploadInfo.getUploadPercent()== 100.0){
request.getSession().setAttribute("uploadInfo", null);
}
}
System.out.println("文件上次情况："+responseContent);
response.getWriter().print(responseContent);
}
}
前台页面upload2.html
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <script src="/UploadFiles/2021-04-02/jquery-2.1.1.js">将项目部署到tomcat(或其他web容器），访问http://172.16.126.128:8080/uploadtest/upload2.html
效果：
代码下载：demo
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
