servlet上传 前端实现
项目中很多地方都用到上传，这里做一个demo，还带进度条
package util.upload;
import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import javax.servlet.ServletException;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = -3100028422371321159L;
private boolean isAllowed;
private String upFileName;
//定义合法后缀名的数组
private String[] allowedExtName=new String[]
{"zip","rar",//压缩文件
"txt","doc","wps","docx","java",//文本
"xls","xlsx",//表格
"ppt","pptx",//幻灯片
"pdf",//pdf
"jpg","jpeg","bmp","gif","png"//图片
};
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码格式为utf-8
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//获取session，保存进度和上传结果，上传开始为nok,当为Ok表示上传完成
HttpSession session=request.getSession();
session.setAttribute("result", "nok");
session.setAttribute("error", "");
String error="";
upFileName="";
isAllowed=false;
//给上传的文件设一个最大值，这里是不得超过100MB
int maxSize=100*1024*1024;
//建立工厂对象和文件上传对象
DiskFileItemFactory factory=new DiskFileItemFactory();
ServletFileUpload upload=new ServletFileUpload(factory);
//建立上传监听器和设置监听器
UploadListener listener=new UploadListener();
session.setAttribute("LISTENER", listener);
upload.setProgressListener(listener);
//上传路径
String path = request.getSession().getServletContext().getRealPath("/upload");
String requestPath = request.getSession().getServletContext().getContextPath()+"/upload";
File dirFile =new File(path); //System.out.println(request.getSession().getServletContext().getContextPath());
//若是文件夹不存在则建立
if (!dirFile .exists() && !dirFile .isDirectory())
{
dirFile .mkdir();
}
//根据日期建立文件夹,保存到对应日期的文件夹下
Date date=new Date();
SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
String subDirName=sdf.format(date);
File subDirFile=new File(path+"/"+subDirName);
if (!subDirFile .exists() && !subDirFile .isDirectory())
{
subDirFile .mkdir();
}
try {
//解析上传请求
List<FileItem> items=upload.parseRequest(request);
Iterator<FileItem> itr=items.iterator();
while(itr.hasNext()){
FileItem item=(FileItem)itr.next();
//判断是否为文件域
if(!item.isFormField()){ if(item.getName()!=null&&!item.getName().equals("")){
//获取上传文件大小和文件名称
long upFileSize=item.getSize();
String fileName=item.getName();
//获取文件后缀名
String[] splitName=fileName.split("//.");
String extName=splitName[splitName.length-1];
//检查文件后缀名
for(String allowed:allowedExtName)
{
if(allowed.equalsIgnoreCase(extName))
{
isAllowed=true;
}
}
if(!isAllowed){
error="上传文件格式不合法！";
break;
}
if(upFileSize>maxSize){
error="您上传的文件太大了，请选择不超过100MB的文件!";
break;
}
//此时文件暂存在服务器的内存中，构造临时对象
File tempFile=new File(makeFileName(fileName));
//指定文件上传服务器的目录及文件名称
File file=new File(path+"/"+subDirName+"/",tempFile.getName());
item.write(file);//第一种写文件方法
upFileName=requestPath+"/"+subDirName+"/"+tempFile.getName();
if(upFileName.equals("")){
error="没选择上传文件！";
}
System.out.println(upFileName);
/*//构造输入流读文件 第二种写文件方法
InputStream is=item.getInputStream();
int length=0;
byte[] by=new byte[1024];
FileOutputStream fos=new FileOutputStream(file);
while((length=is.read(by))!=-1){
fos.write(by, 0, length);
//Thread.sleep(10);
}
fos.close();
//Thread.sleep(1000);*/
}else{
error="没选择上传文件！";
}
}
}
} catch (Exception e) {
e.printStackTrace();
error="上传文件出现错误:"+e.getMessage();
}
if(!error.equals("")){
System.out.println(error);
session.setAttribute("error", error);
}else{
session.setAttribute("result", "OK");
session.setAttribute("filename",upFileName);
}
}
/**
* 为防止文件覆盖的现象发生，要为上传文件产生一个惟一的文件名
* @param filename 原文件名
* @return 生成的惟一文件名
*/
private String makeFileName(String filename){
return UUID.randomUUID().toString() + "_" + filename;
}
}
其中须要引入commons-fileupload-1.3.1.jar,commons-io-2.4.jar
上传过程当中，咱们须要实时获取上传进度等信息，引入的库里为咱们添加了一个ProgressListener接口，咱们再写一个类实现这个接口，上面类中添加该接口css
//建立工厂对象和文件上传对象
DiskFileItemFactory factory=new DiskFileItemFactory();
ServletFileUpload upload=new ServletFileUpload(factory);
//建立上传监听器和设置监听器
UploadListener listener=new UploadListener();
session.setAttribute("LISTENER", listener);
upload.setProgressListener(listener);
下面是这个监听类的具体实现代码html
package util.upload;
import org.apache.commons.fileupload.ProgressListener;
public class UploadListener implements ProgressListener{
private volatile long
bytesRead = 0L,//上传的字节数
contentLength = 0L,//总字节数
item = 0L;
public UploadListener()
{
super();
}
@Override
public void update(long aBytesRead, long aContentLength, int anItem) {
bytesRead = aBytesRead;
contentLength = aContentLength;
item = anItem;
}
public long getBytesRead()
{
return bytesRead;
}
public long getContentLength()
{
return contentLength;
}
public long getItem()
{
return item;
}
}
如今能获取上传进度等信息了，但还须要一个servlet返回给前端，下面实现前端
package util.upload;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
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.ProgressListener;
import com.google.gson.Gson;
/**
获取上传进度,上传路径,错误,上传结果等信息
*/
public class GetProgressServlet extends HttpServlet{
private static final long serialVersionUID = -3596466520775012991L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
UploadListener listener= null;
HttpSession session = request.getSession();
String error=(String) session.getAttribute("error");
String result= (String) session.getAttribute("result");
String fileName=(String) session.getAttribute("filename");
PrintWriter out = response.getWriter();
long bytesRead = 0,contentLength = 0;
if (session != null)
{
listener = (UploadListener)session.getAttribute("LISTENER");
if (listener == null)
{
return;
}
else
{
bytesRead = listener.getBytesRead();//上传的字节数
contentLength = listener.getContentLength();//总字节数
}
//本身定义的返回格式
String rp=bytesRead+","
+contentLength+","
+error+","
+result+","
+fileName;
//System.out.println(rp);
out.print(rp);
/* //返回json格式数据
Map<String,Object> map=new HashMap<String,Object>();
map.put("bytesRead", bytesRead);
map.put("contentLength", contentLength);
map.put("error", error);
map.put("result", result);
map.put("fileName", fileName);
Gson gson=new Gson();
String json=gson.toJson(map);
out.print(json);*/
out.flush();
out.close();
}
}
}
后台上传的功能代码写完了，下面实现上传的前端，首先是htmlhtml5
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<script type="text/javascript" src="js/upfile.js" charset="utf-8"></script>
<link rel="stylesheet" type="text/css" href="css/upfile.css">
</head>
<body >
<a href="javascript:addOne()">添加</a>
<div id="target">
<input type="file" id="file" name="file" onchange="addfile(event)" multiple/>
</div>
<span id="test">0</span>
</body>
</html>
界面比较简单，就一个添加的a标签，负责上传的input隐藏起来
css文件主要渲染的上传进度的显示java
更多内容： https://www.shangmayuan.com
#file {
display: none;
}
.pro{
width:500px;
}
.pborder {
position: relative;
width: 500px; /* 宽度 */
border: 1px solid #B1D632;
padding: 1px;
}
.drawpro {
width: 0px;
display: block;
position: relative;
background: #B1D632;
color: #333333;
height: 20px; /* 高度 */
line-height: 20px; /* 必须和高度一致，文本才能垂直居中 */
}
.pspan {
position: absolute;
width: 500px;
text-align: center;
font-weight: bold;
}
接着是前端的重点，js文件web
//显示上传信息的html
var upfile_html = '<div class="pborder"><div class="drawpro">'
+ '<span class="pspan">0%</span></div></div><span name="path"></span><img src="common/upload/images/del.png" width="20" height="20" name="del" onclick=abortUpload(this)>';
var targetDIV_id = "target";//显示上传文件的目标div的ID
var httpXML = null;//发送上传请求的XMLHttpRequest对象
var httpProgress = null;//发送请求进度信息的XMLHttpRequest对象
var oldFileList = new Array();//修改时保存已有附件信息的列表
var uplist = new Array();//保存上传文件的列表
var f_input;//上传文件的input对象
var flag = true;//是否能够上传下一个文件标志
var uurl = "Upload";//上传文件的请求url
var gurl = "getProgress";//获取上传进度信息的url
var cancelFlag = 0;//取消标志
var timer, waittimer;//定时器
var nowID = 0;//正在上传文件的id
var ID = 0;//队列中最后一个文件的id
/**
* 文件对象
*/
function UploadFile(id, file) {
this.id = id;
this.file = file;
this.state = 0;
this.path = "";
}
/**
* 初始化的方法
*/
window.onload = function init() {
f_input = document.getElementById("file");
var tdiv = document.getElementById(targetDIV_id);
var oldspan = tdiv.getElementsByTagName("SPAN");
for ( var i = 0; i < oldspan.length; i++) {
oldFileList.push(oldspan[i].getAttribute("name"));
}
}
/**
* 选择一个文件上传
*/
function addOne() {
f_input.value = null;
f_input.click();
}
/**
* 选中文件后将文件对象添加到队列，开始上传
*
*/
function addfile(evt) {
var f = f_input.files[0];
if (f != undefined) {
var uf = new UploadFile(ID, f);
uplist.push(uf);
var div = document.createElement("DIV");
div.setAttribute("id", "pro" + (ID));
div.setAttribute("class", "pro");
div.innerHTML = upfile_html;
var targetDiv = document.getElementById(targetDIV_id);
targetDiv.appendChild(div);
div.getElementsByTagName("SPAN")[1].innerHTML = "文件名:"
+ uplist[ID].file.name;
waittimer = setInterval("upload()", 1000);
ID++;
}
}
/**
* 将队列中的文件上传
*/
function upload() {
if (flag == true) {
if (uplist.length > 0) {
var uf;
for ( var i = 0; i < uplist.length; i++) {
if (uplist[i].state == 0) {
uf = uplist[i];
uplist[i].state = 1;
break;
}
}
if (uf != undefined & uf != null) {
flag = false;
if (window.XMLHttpRequest) {
httpUP = new XMLHttpRequest();
} else if (window.ActiveXObject) {
httpUP = new ActiveXObject("Microsoft.XMLHTTP");
}
var formData = new FormData();
formData.append("file", uf.file);
httpUP.open("POST", uurl, true);
httpUP.upload.addEventListener('progress', uploadProgress, false);
httpUP.send(formData);
nowID = uf.id;
timer = setInterval("getP()", 50);
}
}
}
}
/**
* 获取上传进度等信息
*/
function getP() {
if (window.XMLHttpRequest) {
httpProgress = new XMLHttpRequest();
} else if (window.ActiveXObject) {
httpProgress = new ActiveXObject("Microsoft.XMLHTTP");
}
httpProgress.onreadystatechange = onProgress;
httpProgress.open("post", gurl, true);
httpProgress.setRequestHeader("Content-type",
"application/x-www-form-urlencoded");
httpProgress.send("&timeStamp=" + (new Date()).getTime());
}
/**
* 处理返回的上传信息，显示到界面
*/
function onProgress() {
if (httpProgress.readyState == 4 && httpProgress.status == 200) {
result = httpProgress.responseText;
var result = result.replace(/(^/s*)|(/s*$)/g, "");
var res = result.split(",");
var now = parseInt(res[0]);
var all = parseInt(res[1]);
var err = res[2];
var state = res[3];
var path = res[4];
var per = (now / all * 100).toFixed(2);
var prodiv = document.getElementById("pro" + nowID);
if (prodiv != null & prodiv != undefined) {
if (err != "" & err != null & err.length > 0) {
window.clearInterval(timer);
if (cancelFlag == 1) {
err = "上传终止";
cancelFlag = 0;
}
prodiv.getElementsByTagName("DIV")[0].style.display = "none";
prodiv.getElementsByTagName("SPAN")[1].innerHTML = err;
httpUP.abort();
flag = true;
uplist[nowID].state = 3;
return;
}
if (state == "OK") {
prodiv.getElementsByTagName("DIV")[0].style.display = "none";
var tmpf = uplist[nowID].file;
prodiv.getElementsByTagName("SPAN")[1].innerHTML = "文件名:"
+ tmpf.name;
window.clearInterval(timer);
flag = true;
uplist[nowID].state = 2;
uplist[nowID].path = path;
return;
}
prodiv.getElementsByTagName("DIV")[1].style.width = per * 5 + "px";
prodiv.getElementsByTagName("SPAN")[0].innerHTML = per + "%";
}
}
}
/**
* 取消上传的方法
*/
function abortUpload(obj) {
var idStr = obj.parentNode.id;
var id = idStr.slice(3);
if (uplist[id].state == 1) {
httpUP.abort();
flag = true;
cancelFlag = 1;
} else {
uplist[id].state = 3;
}
document.getElementById(idStr).remove();
}
/**
* 获取上传文件的路径
* @returns 格式化后字符串
*/
function getFileListStr() {
var str = "";
if (oldFileList.length > 0) {
for ( var i = 0; i < oldFileList.length; i++) {
if (oldFileList[i] != null & oldFileList[i] != ""
& oldFileList[i] != undefined) {
str = str + oldFileList[i] + ",";
}
}
}
for ( var i = 0; i < uplist.length; i++) {
var f = uplist[i];
if (f.state == 2) {
str = str + f.path + ",";
}
}
return str;
}
/**
* 移除修改时已有的旧附件
*
*/
function removeOld(btn) {
var num = btn.getAttribute("name");
oldFileList[num - 1] = null;
btn.parentNode.remove();
}
function uploadProgress(e) {
if (e.lengthComputable) {
var iBytesUploaded = e.loaded;
var iBytesTotal = e.total;
document.getElementById("test").innerHTML=iBytesUploaded+"/"+iBytesTotal;
}
}
使用ajax发送上传文件，获取上传进度，结果等信息。
使用的html5的file API，因此必须ie9以上的才能够兼容，火狐还有个问题，ajax请求不当即返回，直到全部ajax请求都发送完了，才都返回同一个结果，这就致使上传进度不显示。不过上传进度信息也可使用html5的file api获取，其中加了一点代码，页面下面test的div里的数值就是在前端获取到的进度。ajax
上传的都实现完了，接着是处理上传后的临时文件，由于使用的uuid命名文件，因此文件会生成不少，没用的须要定时处理。使用ServletContextListener：
在 Servlet API 中有一个 ServletContextListener 接口，它可以监听 ServletContext 对象的生命周期，实际上就是监听 Web 应用的生命周期。apache
当Servlet 容器启动或终止Web 应用时，会触发ServletContextEvent 事件，该事件由ServletContextListener 来处理。在 ServletContextListener 接口中定义了处理ServletContextEvent 事件的两个方法。
利用其特性，实现定时删除临时文件的功能，代码以下：json
package util.upload;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
/**
* 时间监听器
*
*
*/
public class TempFileListener implements ServletContextListener {
private Timer timer;
private SystemTaskTest systemTask;
private static String every_time_run;
static {
Properties prop = new Properties();
InputStream inStrem = TempFileManager.class.getClassLoader()
.getResourceAsStream("tempfile.properties");
try {
prop.load(inStrem);
System.out.println(inStrem);
every_time_run = prop.getProperty("every_time_run");
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
inStrem.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
// 监听器初始方法
public void contextInitialized(ServletContextEvent sce) {
timer = new Timer();
systemTask = new SystemTaskTest(sce.getServletContext()
.getRealPath("/"), sce.getServletContext());
try {
System.out.println("定时器已启动");
// 监听器获取网站的根目录
String path = sce.getServletContext().getRealPath("/");
Long time = Long.parseLong(every_time_run) * 1000;// 循环执行的时间
System.out.println("time" + time);
// 第一个参数是要运行的代码，第二个参数是从何时开始运行，第三个参数是每隔多久在运行一次。重复执行
timer.schedule(systemTask, 10000, time);
System.out.println("已经添加任务调度表");
} catch (Exception e) {
e.printStackTrace();
}
}
public void contextDestroyed(ServletContextEvent sce) {
try {
timer.cancel();
} catch (Exception e) {
}
}
}
/**
* 时间任务器
*
*/
class SystemTaskTest extends TimerTask {
private ServletContext context;
private String path;
public SystemTaskTest(String path, ServletContext context) {
this.path = path;
this.context = context;
}
/**
* 把要定时执行的任务就在run中
*/
public void run() {
TempFileManager etf;
try {
System.out.println("开始执行任务!");
// 须要执行的代码
System.out.println(new Date().toLocaleString());
etf = new TempFileManager(path);
etf.run();
System.out.println("指定任务执行完成!");
} catch (Exception e) {
e.printStackTrace();
}
}
}
上面只是监听器，负责定时调用删除临时文件的方法，具体实现是下面的类
package util.upload;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.Properties;
/**
* 删除服务器上的文件
*
*/
public class TempFileManager implements Runnable {
private String path;//路径
private static String RETENTION_TIME = "1440";// 文件保存的时间 一天单位分
static {
Properties prop = new Properties();
InputStream inStrem = TempFileManager.class.getClassLoader()
.getResourceAsStream("execl.properties");
try {
prop.load(inStrem);
RETENTION_TIME = prop.getProperty("file_retention_time");
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
inStrem.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 构造函数。初始化参数
* @param path
*/
public TempFileManager(String path) {
this.path = path;
}
/**
* 把线程要执行的代码放在run()中
*/
public void run() {
System.out.println("文件管理开始=========");
path = path + "upload";
System.out.println("文件管理路径===" + path);
File file = new File(path);
deletefiles(file);
}
/**
* 批量删除文件
*
* @param folder
*/
public void deletefiles(File folder) {
if(folder.isDirectory()){
File[] files = folder.listFiles();
if(files.length<=0){
if(!folder.getAbsolutePath().equalsIgnoreCase(path)){
if(canDeleteFile(folder)){
if (folder.delete()) {
System.out.println("文件夹" + folder.getName() + "删除成功!");
} else {
System.out.println("文件夹" + folder.getName()
+ "删除失败!此文件夹内的文件可能正在被使用");
}
}
}
}
for (int i = 0; i < files.length; i++) {
if(files[i].isDirectory())
{
deletefiles(files[i]);
}else{
deleteFile(files[i]);
}
}
}
}
/**
* 删除文件
*
* @param file
*/
private void deleteFile(File file) {
try {
if (file.isFile()) {
// 删除符合条件的文件
if (canDeleteFile(file)) {
if (file.delete()) {
System.out.println("文件" + file.getName() + "删除成功!");
} else {
System.out.println("文件" + file.getName()
+ "删除失败!此文件可能正在被使用");
}
} else {
}
} else {
System.out.println("没有能够删除的文件了");
}
} catch (Exception e) {
System.out.println("删除文件失败========");
e.printStackTrace();
}
}
/**
* 判断文件是否可以被删除
*/
private boolean canDeleteFile(File file) {
Date fileDate = getfileDate(file);
Date date = new Date();
long time = (date.getTime() - fileDate.getTime()) / 1000 / 60
- Integer.parseInt(RETENTION_TIME);// 当前时间与文件间隔的分钟
// System.out.println("time=="+time);
if (time > 0) {
return true;
} else {
return false;
}
}
/**
* 获取文件最后的修改时间
*
* @param file
* @return
*/
private Date getfileDate(File file) {
long modifiedTime = file.lastModified();
Date d = new Date(modifiedTime);
return d;
}
}
正文到此结束
- 本文标签： web js 数据 时间 json final ACE IO apache https UI 代码 DOM volatile 生命 图片 rand zip ip map HTML5 Document 参数 删除 ORM tag update servlet 网站 Google parse onchange http Property stream java node cat API 解析 文件上传 ask JavaScript equals 目录 tab 线程 管理 HTML list src message session ssl tar CSS App value Ajax 监听器 HashMap 服务器 IDE CTO XML setInterval 任务调度 id
- 版权声明： 本文为互联网转载文章，出处已在文章中说明(部分除外)。如果侵权，请联系本站长删除，谢谢。
- 本文海报： 生成海报一 生成海报二
热门推荐
相关文章
近期评论
-
文章和留言都翻到11页了 没有OOM
-
-
朋友，翻页到11页，及以后，会出现OOM，无法访问
-
-
搞个gitee的项目
-
-
版本号是多少，你可以下载哪个代码仓库，jdk选1.8 直接跑就行
-
-
-
Loading...
![[HBLOG]公众号](https://www.liuhaihua.cn/img/qrcode_gzh.jpg)
