首先Spring是一个非常成熟的J2EE框架，其非入侵式的架构为系统的集成和扩展提供了最大的可能。所以Spring MVC下实现进度监听非常容易，甚至不需要改以前的上传业务代码，具体实现分三个步骤：1、接管CommonsMultipartResolver，重写针对文件上传的请求。2、在第一步中写入监听，以获取上传进度。3、修改上传部分的配置文件。具体见代码1、CommonsMultipartResolver代码
package com.van.utils.upload.handle;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUpload;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.springframework.web.multipart.MaxUploadSizeExceededException;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import com.van.utils.upload.listener.PJProgressListener;
/**
* 重写CommonsMultipartResolver以监听文件上传进度
* @author Van
* @date 2012-12-12
*/
public class PJCommonsMultipartResolver extends CommonsMultipartResolver {
private HttpServletRequest request;
protected FileUpload newFileUpload(FileItemFactory fileItemFactory) {
ServletFileUpload upload = new ServletFileUpload(fileItemFactory);
upload.setSizeMax(-1);
if (request != null) {
HttpSession session = request.getSession();
PJProgressListener uploadProgressListener = new PJProgressListener(session);
upload.setProgressListener(uploadProgressListener);
}
return upload;
}
public MultipartHttpServletRequest resolveMultipart(
HttpServletRequest request) throws MultipartException {
this.request = request;// 获取到request,要用到session
return super.resolveMultipart(request);
}
@SuppressWarnings("unchecked")
@Override
public MultipartParsingResult parseRequest(HttpServletRequest request) throws MultipartException {
HttpSession session = request.getSession();
String encoding = "utf-8";
FileUpload fileUpload = prepareFileUpload(encoding);
PJProgressListener uploadProgressListener = new PJProgressListener(session);
fileUpload.setProgressListener(uploadProgressListener);
try {
List fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
return parseFileItems(fileItems, encoding);
}
catch (FileUploadBase.SizeLimitExceededException ex) {
throw new MaxUploadSizeExceededException(fileUpload.getSizeMax(), ex);
}
catch (FileUploadException ex) {
throw new MultipartException("Could not parse multipart servlet request", ex);
}
}
}
PJProgressListener 代码：
package com.van.utils.upload.listener;
import javax.servlet.http.HttpSession;
import org.apache.commons.fileupload.ProgressListener;
import com.van.utils.upload.entity.ProgressEntity;
public class PJProgressListener implements ProgressListener{
private HttpSession session;
public PJProgressListener() {
}
public PJProgressListener(HttpSession _session) {
session=_session;
ProgressEntity ps = new ProgressEntity();
session.setAttribute("upload_ps", ps);
}
public void update(long pBytesRead, long pContentLength, int pItems) {
ProgressEntity ps = (ProgressEntity) session.getAttribute("upload_ps");
ps.setpBytesRead(pBytesRead);
ps.setpContentLength(pContentLength);
ps.setpItems(pItems);
//更新
session.setAttribute("upload_ps", ps);
}
}
上传进度信息记录实体类：
package com.van.utils.upload.entity;
/**
* 文件上传进度信息
* @author Van
*
*/
public class ProgressEntity {
private long pBytesRead = 0L;
private long pContentLength = 0L;
private int pItems;
public long getpBytesRead() {
return pBytesRead;
}
public void setpBytesRead(long pBytesRead) {
this.pBytesRead = pBytesRead;
}
public long getpContentLength() {
return pContentLength;
}
public void setpContentLength(long pContentLength) {
this.pContentLength = pContentLength;
}
public int getpItems() {
return pItems;
}
public void setpItems(int pItems) {
this.pItems = pItems;
}
@Override
public String toString() {
return "ProgressEntity [pBytesRead=" + pBytesRead + ", pContentLength="
+ pContentLength + ", pItems=" + pItems + "]";
}
}
配置文件部分修改：
将org.springframework.web.multipart.commons.CommonsMultipartResolver替换成：com.van.utils.upload.handle.PJCommonsMultipartResolver
作者：Java高级技术
链接：https://www.jianshu.com/p/4680e5929366
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