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struts2结合common.fileUpload实现文件带进度条上传
发布时间：2019-10-09 11:34:28 编辑：miki浏览（1304）评论（3）
最后,项目还残存的问题就是:明明是每隔500ms向后台请求的进度信息,但是实际上后台并不能够在这段时间内返回对应的信息。亟待优化!
效果图如下:
获取文件上传信息的基本步骤:经测试有效
上传文件时如何获取上传进度信息?
从网上查一下资料就可以知道struts2对文件上传的request请求做了封装,也就是说在调用上传文件的action时就已经上传temp完成了。
那么既然这样,我们就可以重写struts2封装request的类:org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest;
由于这个类的许多方法都是private的,那么也就是说我们是无法通过extends来重写父类的一些方法的。怎么办呢?
暴力一点!
直接自定义一个JakartaMultiPartRequest类型的类,把父类的方法全部copy过来,然后在struts.xml中配置:
....
接下来我们实现上述配置文件中的MultiPartRequest类:
通过intellij的反编译插件,我们decode JakartaMultiPartRequest这个类:源码如下—-大量代码来袭,直接copy这部分吧 不用细看
/*
* $Id: JakartaMultiPartRequest.java 1384107 2012-09-12 20:14:23Z lukaszlenart $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.struts2.dispatcher.multipart;
import com.opensymphony.xwork2.LocaleProvider;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.LocalizedTextUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.RequestContext;
import org.apache.commons.fileupload.disk.DiskFileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.struts2.StrutsConstants;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
/**
* Multipart form data request adapter for Jakarta Commons Fileupload package.
*/
public class JakartaMultiPartRequest implements MultiPartRequest {
static final Logger LOG = LoggerFactory.getLogger(JakartaMultiPartRequest.class);
// maps parameter name -> List of FileItem objects
protected Map> files = new HashMap>();
// maps parameter name -> List of param values
protected Map> params = new HashMap>();
// any errors while processing this request
protected List errors = new ArrayList();
protected long maxSize;
private Locale defaultLocale = Locale.ENGLISH;
@Inject(StrutsConstants.STRUTS_MULTIPART_MAXSIZE)
public void setMaxSize(String maxSize) {
this.maxSize = Long.parseLong(maxSize);
}
@Inject
public void setLocaleProvider(LocaleProvider provider) {
defaultLocale = provider.getLocale();
}
/**
* Creates a new request wrapper to handle multi-part data using methods adapted from Jason Pell's
* multipart classes (see class description).
*
* @param saveDir the directory to save off the file
* @param request the request containing the multipart
* @throws java.io.IOException is thrown if encoding fails.
*/
public void parse(HttpServletRequest request, String saveDir) throws IOException {
try {
setLocale(request);
processUpload(request, saveDir);
} catch (FileUploadBase.SizeLimitExceededException e) {
if (LOG.isWarnEnabled()) {
LOG.warn("Request exceeded size limit!", e);
}
String errorMessage = buildErrorMessage(e, new Object[]{e.getPermittedSize(), e.getActualSize()});
if (!errors.contains(errorMessage)) {
errors.add(errorMessage);
}
} catch (Exception e) {
if (LOG.isWarnEnabled()) {
LOG.warn("Unable to parse request", e);
}
String errorMessage = buildErrorMessage(e, new Object[]{});
if (!errors.contains(errorMessage)) {
errors.add(errorMessage);
}
}
}
protected void setLocale(HttpServletRequest request) {
if (defaultLocale == null) {
defaultLocale = request.getLocale();
}
}
protected String buildErrorMessage(Throwable e, Object[] args) {
String errorKey = "struts.messages.upload.error." + e.getClass().getSimpleName();
if (LOG.isDebugEnabled()) {
LOG.debug("Preparing error message for key: [#0]", errorKey);
}
return LocalizedTextUtil.findText(this.getClass(), errorKey, defaultLocale, e.getMessage(), args);
}
private void processUpload(HttpServletRequest request, String saveDir) throws FileUploadException, UnsupportedEncodingException {
for (FileItem item : parseRequest(request, saveDir)) {
if (LOG.isDebugEnabled()) {
LOG.debug("Found item " + item.getFieldName());
}
if (item.isFormField()) {
processNormalFormField(item, request.getCharacterEncoding());
} else {
processFileField(item);
}
}
}
private void processFileField(FileItem item) {
if (LOG.isDebugEnabled()) {
LOG.debug("Item is a file upload");
}
// Skip file uploads that don't have a file name - meaning that no file was selected.
if (item.getName() == null || item.getName().trim().length() < 1) {
LOG.debug("No file has been uploaded for the field: " + item.getFieldName());
return;
}
List values;
if (files.get(item.getFieldName()) != null) {
values = files.get(item.getFieldName());
} else {
values = new ArrayList();
}
values.add(item);
files.put(item.getFieldName(), values);
}
private void processNormalFormField(FileItem item, String charset) throws UnsupportedEncodingException {
if (LOG.isDebugEnabled()) {
LOG.debug("Item is a normal form field");
}
List values;
if (params.get(item.getFieldName()) != null) {
values = params.get(item.getFieldName());
} else {
values = new ArrayList();
}
// note: see http://jira.opensymphony.com/browse/WW-633
// basically, in some cases the charset may be null, so
// we're just going to try to "other" method (no idea if this
// will work)
if (charset != null) {
values.add(item.getString(charset));
} else {
values.add(item.getString());
}
params.put(item.getFieldName(), values);
item.delete();
}
private List parseRequest(HttpServletRequest servletRequest, String saveDir) throws FileUploadException {
DiskFileItemFactory fac = createDiskFileItemFactory(saveDir);
ServletFileUpload upload = new ServletFileUpload(fac);
upload.setSizeMax(maxSize);
return upload.parseRequest(createRequestContext(servletRequest));
}
private DiskFileItemFactory createDiskFileItemFactory(String saveDir) {
DiskFileItemFactory fac = new DiskFileItemFactory();
// Make sure that the data is written to file
fac.setSizeThreshold(0);
if (saveDir != null) {
fac.setRepository(new File(saveDir));
}
return fac;
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getFileParameterNames()
*/
public Enumeration getFileParameterNames() {
return Collections.enumeration(files.keySet());
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getContentType(java.lang.String)
*/
public String[] getContentType(String fieldName) {
List items = files.get(fieldName);
if (items == null) {
return null;
}
List contentTypes = new ArrayList(items.size());
for (FileItem fileItem : items) {
contentTypes.add(fileItem.getContentType());
}
return contentTypes.toArray(new String[contentTypes.size()]);
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getFile(java.lang.String)
*/
public File[] getFile(String fieldName) {
List items = files.get(fieldName);
if (items == null) {
return null;
}
List fileList = new ArrayList(items.size());
for (FileItem fileItem : items) {
File storeLocation = ((DiskFileItem) fileItem).getStoreLocation();
if (fileItem.isInMemory() &;&; storeLocation != null &;&; !storeLocation.exists()) {
try {
storeLocation.createNewFile();
} catch (IOException e) {
if (LOG.isErrorEnabled()) {
LOG.error("Cannot write uploaded empty file to disk: " + storeLocation.getAbsolutePath(), e);
}
}
}
fileList.add(storeLocation);
}
return fileList.toArray(new File[fileList.size()]);
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getFileNames(java.lang.String)
*/
public String[] getFileNames(String fieldName) {
List items = files.get(fieldName);
if (items == null) {
return null;
}
List fileNames = new ArrayList(items.size());
for (FileItem fileItem : items) {
fileNames.add(getCanonicalName(fileItem.getName()));
}
return fileNames.toArray(new String[fileNames.size()]);
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getFilesystemName(java.lang.String)
*/
public String[] getFilesystemName(String fieldName) {
List items = files.get(fieldName);
if (items == null) {
return null;
}
List fileNames = new ArrayList(items.size());
for (FileItem fileItem : items) {
fileNames.add(((DiskFileItem) fileItem).getStoreLocation().getName());
}
return fileNames.toArray(new String[fileNames.size()]);
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getParameter(java.lang.String)
*/
public String getParameter(String name) {
List v = params.get(name);
if (v != null &;&; v.size() > 0) {
return v.get(0);
}
return null;
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getParameterNames()
*/
public Enumeration getParameterNames() {
return Collections.enumeration(params.keySet());
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getParameterValues(java.lang.String)
*/
public String[] getParameterValues(String name) {
List v = params.get(name);
if (v != null &;&; v.size() > 0) {
return v.toArray(new String[v.size()]);
}
return null;
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#getErrors()
*/
public List getErrors() {
return errors;
}
/**
* Returns the canonical name of the given file.
*
* @param filename the given file
* @return the canonical name of the given file
*/
private String getCanonicalName(String filename) {
int forwardSlash = filename.lastIndexOf("/");
int backwardSlash = filename.lastIndexOf("\\");
if (forwardSlash != -1 &;&; forwardSlash > backwardSlash) {
filename = filename.substring(forwardSlash + 1, filename.length());
} else if (backwardSlash != -1 &;&; backwardSlash >= forwardSlash) {
filename = filename.substring(backwardSlash + 1, filename.length());
}
return filename;
}
/**
* Creates a RequestContext needed by Jakarta Commons Upload.
*
* @param req the request.
* @return a new request context.
*/
private RequestContext createRequestContext(final HttpServletRequest req) {
return new RequestContext() {
public String getCharacterEncoding() {
return req.getCharacterEncoding();
}
public String getContentType() {
return req.getContentType();
}
public int getContentLength() {
return req.getContentLength();
}
public InputStream getInputStream() throws IOException {
InputStream in = req.getInputStream();
if (in == null) {
throw new IOException("Missing content in the request");
}
return req.getInputStream();
}
};
}
/* (non-Javadoc)
* @see org.apache.struts2.dispatcher.multipart.MultiPartRequest#cleanUp()
*/
public void cleanUp() {
Set names = files.keySet();
for (String name : names) {
List items = files.get(name);
for (FileItem item : items) {
if (LOG.isDebugEnabled()) {
String msg = LocalizedTextUtil.findText(this.getClass(), "struts.messages.removing.file",
Locale.ENGLISH, "no.message.found", new Object[]{name, item});
LOG.debug(msg);
}
if (!item.isInMemory()) {
item.delete();
}
}
}
}
}
好的,我们把上面这部分代码copy到我们自定义的public class MultiPartRequest extends JakartaMultiPartRequest {}中
复制粘贴完了之后,我们要ctrl f找到parseRequest方法。在这里,我们要设置文件上传进度监听器
/**
* 自定义的parseRequest方法
* @param servletRequest
* @param saveDir
* @return
* @throws FileUploadException
*/
private List parseRequest(HttpServletRequest servletRequest, String saveDir) throws FileUploadException {
System.out.println("调用parseRequest方法");
UploadProgressListener listener = new UploadProgressListener(servletRequest);
DiskFileItemFactory fac = createDiskFileItemFactory(saveDir);
ServletFileUpload upload = new ServletFileUpload(fac);
upload.setSizeMax(maxSize);
upload.setProgressListener(listener);
System.out.println("设置监听器成功");
return upload.parseRequest(createRequestContext(servletRequest));
}
在上面这个代码片段中可以看到:我们new了一个监听器UploadProgressListener 的实例,然后调用了ServletFileUpload .setProgressListener(listener)方法。也就是说:这里的监听器与我们以前写过的request,session等等监听器不同,不需要在web.xml中配置。这里只需要一行代码即可解决。
那么我们就来实现这个监听器吧!
这个监听器需要实org.apache.commons.fileupload.ProgressListener这个接口:我们直接implement一下。
在update方法中我们可以获取到已上传的文件长度,上传的文件的总长度,当前上传第几个文件。(当你上传一个文件的时候,打印日志就会发现这里会输出2。个人猜测是先上传到temp然后再上传到指定路径…)
我们在update方法中设置了文件上传状态实体类的实例,并且保存到session。这一步就是能让前端使用ajax访问到文件当前的上传进度信息。
package listener; import entity.FileUploadProgress; import org.apache.commons.fileupload.ProgressListener; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; /** * Created by zipple on 2017/10/13. * 监听文件上传情况 * 实现org.apache.commons.fileupload.ProgressListener接口 */
/**
* 2018.11.27 miki 监听文件上传进度的监听器
*
*/
public class UploadProgress implements ProgressListener {
HttpSession session;
/*
* 实时更新上传进度
* arg0：当前上传文件的大小
* arg1:总共需要上传的大小
* arg2：剩余上传文件的大小
*/
public void update(long arg0, long arg1, int arg2) {
// TODO Auto-generated method stub
if(arg1==0L){
return;
}
//创造json格式参数
String value="var info={read:"+arg0+",total:"+arg1+",items:"+1+"}"; //items:"+arg2+" d多文件上传的时候，使用arg2
// System.out.println(value);
session.setAttribute("progress", value); //上传完毕后，记得清除上传过后的进度条session
}
public UploadProgress(HttpSession session){
this.session=session;
}
}
前端获取后台文件上传的进度信息
上传文件可大致分为两个阶段:1. 上传到服务器上，在临时目录中 2.从临时目录中把文件移到指定目录(由自己写的action处理),而struts2.的监听器只监听
public String upload()throws Exception{
//2017.11.16 21:58 miki 加载网页静态化缓存路径
Properties prop = new Properties();
try {
prop.load(this.getClass().getClassLoader().getResourceAsStream("resource.properties"));
} catch (IOException e1) {
throw new RuntimeException(e1);
}
//2017.11.16 20:37 取静态资源中常量
// String HTML_GEN_PATH = prop.getProperty("HTML_GEN_PATH");//静态资源存储路径
HttpServletResponse response=ServletActionContext.getResponse();
HttpSession session=request.getSession();
user=(User) session.getAttribute("currentUser");
if(user==null){
request.getRequestDispatcher("error.jsp").forward(request, response);
}
System.out.println("上传文件名为："+uploadFileName);
shop=shopService.getShopByuserId(user.getId());
// 2017.08.05 miki 文件二次命名，作为下载url链接，采用uuid加密命名，并截取2-18位字符，二次加密，增加安全性
String imageName = "file_"+RadomUtil.getUUID().substring(2, 18)+uploadFileName.substring(uploadFileName.lastIndexOf("."));
File newfile = new File(ServletActionContext.getServletContext().getRealPath("/image_upload/source_upload/file")+"\\"+imageName);
IOUtils.cp(upload, newfile); //因为要设置表单里没有的属性（setImage(),）所以重新创造了一个photo对象
//清除上传过后的进度条session
session.setAttribute("progress", null);
source.setPath(imageName);
source.setUser(user);
source.setShop(shop);
source.setUpload_time(new Date());
sourceService.save(source);
user.setScore(user.getScore()+5);
shop.setSourceNum(shop.getSourceNum()+1);
shopService.save(shop);
userService.saveUser(user);
// /*
// * 2017.11.16 20:31 网页静态化实例
// */
// try {
// User vistor=(User) session.getAttribute("currentUser");
// if (StringUtil.isEmpty(page)) {
// page="1";
// }
// PageBean pageBean=new PageBean(Integer.parseInt(page), 6);
// sourceList=sourceService.getSourcesByShopId(shop.getId(), pageBean);
// long total=sourceService.getSourceCountByuserId(shop.getUser().getId());
// StringBuffer param=new StringBuffer();
// param.append("shopId="+shop.getId());
// pageCode=PageUtil.genPagination(request.getContextPath()+"/shop/Shop_view.action", total, Integer.parseInt(page), 6,param.toString());
//
//
// //创建一个数据集，Map将data封装进去
// Map data=new HashMap<>();
// data.put("vistor", vistor);
// data.put("user", user);
// data.put("shop", shop);
// data.put("sourceList", sourceList);
// data.put("pageCode", pageCode);
// //加载模板对象
// Configuration configuration=freeMarkerConfigurer.getConfiguration();
// Template template = configuration.getTemplate("shop.ftl");
// //创建一个输出流，指定目录及文件名
// Writer out=new FileWriter(HTML_GEN_PATH +shop.getId()+ ".html");
// //生成静态页面
// template.process(data, out);
// //关闭流
// out.close();
//
// } catch (Exception e) {
// // TODO: handle exception
// e.printStackTrace();
// }
return "su";
}
返回json数据的struts.xml配置如下:
shop/Shop_upload.action
项目做到这里,后端的事情已经做完了。接下来就是前端显示进度条的事情。需要的同学可以继续往下看咯。
前端那些事儿——css实现进度条控件
css:可以直接copy,无需细看(firefox下测试无问题)
控制进度条代码:在提交文件时同步调用此计时器即可。
...
if('${shop.sourceNum}'=='${shop.maxNum}'){
$("#error").html("*您已达到资源上传上限，请升级权限再来*");
return false;
}
$("#error").html("");
createProgress();
//getProgress(); //定时刷新
setTimeout("getProgressBar()",1000);
return true;
/**
* 展示上传进度条
*/
关键字词：struts2；文件上传；进度条
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