servlet+jquery实现文件上传进度条示例代码

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="js/jquery-2.1.1.js" type="text/javascript"></script> 

<script >
var falseNum = 0;
$(document).ready(function(){
  $('#subbut').bind('click',
      function(){
        $('#fForm').submit();
        var eventFun = function(){
          $.ajax({
            type: 'GET',
            url: '/uploadtest/UploadFileProgressServlet.do',
            data: {},
            dataType: 'text',
            success : function(resData){
              //如果10次都失败，那就不要继续访问了
              if(falseNum > 10){
               window.clearInterval(intId);
               return;
              }
              var obj = eval("("+resData+")");
              if(obj.data == 'NoData'){
                falseNum ++ ;
                return;
              }
              $("#graphbox").css('display','block');
              $(".progressbar").css('width',obj.uploadPrecent+'%');
              $("#uploadPer").html(obj.uploadPrecent+'%');
              $("#progressInfo").html('总大小：'+obj.totalSize
                  +'，速度：'+obj.uploadSpeed
                  +'%，剩余时间：'+obj.remainTime+'，已用时间：'+obj.useTime);
              if(obj.uploadPrecent == 100){
                window.clearInterval(intId);
                $("#progressInfo").html("上传成功！");
              }
        }});};
        var intId = window.setInterval(eventFun,500);
  });
});
</script>
<style>
#graphbox{
border:1px solid #e7e7e7;
padding:5px;
width:350px;
background-color:#f8f8f8;
margin:5px 0;
display:none;
}
.graph{
position:relative;
background-color:#F0EFEF;
border:1px solid #cccccc;
padding:2px;
font-size:10px;
font-weight:500;
}
.graph .progressbar{
position:relative;
text-align:right;
color:#ffffff;
height:10px;
line-height:10px;
font-family:Arial;
display:block;
}
.graph .progressbar{background-color:#66CC33;} 

</style>
</head>
<body>
    <form id='fForm' class="form-actions form-horizontal" action="/uploadtest/UploadFileServlet.do"
       encType="multipart/form-data" target="uploadf" method="post">
         <div class="control-group">
          <label class="control-label">上传文件:</label>
          <div class="controls">
            <input type="file" name="file" style="width:350px"></br>
            <input type="file" name="file2" style="width:350px"></br>
            <button type="button" id="subbut" class="btn">上传</button>
          </div>
          <div id="graphbox">
            <div class="graph">
            <span class="progressbar" style="width:0%;"><span id="uploadPer"></span></span>
            </div>
          </div>
          <div id='progressInfo'>
          </div>
        </div>
    </form>
    <iframe name="uploadf" style="display:none"></iframe>
</body>
</html>

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

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