SpringMVC 监听文件上传进度

Spring MVC 监听文件上传进度

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。

重写CommonsMultipartResolver以监听文件上传进度

package com.xc.common.resolver;

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.xc.common.listener.XcProgressListener;

/**
 * 重写CommonsMultipartResolver以监听文件上传进度
 */
public class XcCommonsMultipartResolver 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();
            XcProgressListener uploadProgressListener = new XcProgressListener(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);
    }

    @Override
    public MultipartParsingResult parseRequest(HttpServletRequest request) throws MultipartException {

        HttpSession session = request.getSession();

        String encoding = "utf-8";
        FileUpload fileUpload = prepareFileUpload(encoding);

        XcProgressListener uploadProgressListener = new XcProgressListener(session);
        fileUpload.setProgressListener(uploadProgressListener);
        try {
            List<FileItem> 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);
        }
    }

}

实现ProgressListener监听器

package com.xc.common.listener;

import javax.servlet.http.HttpSession;
import org.apache.commons.fileupload.ProgressListener;
import com.xc.entity.common.ProgressEntity;

public class XcProgressListener implements ProgressListener {
    private HttpSession session;

    public XcProgressListener() {
    }

    public XcProgressListener(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);
        System.out.println(ps.toString());
        // 更新
        session.setAttribute("upload_ps", ps);
    }

}

创建上传进度信息记录实体类

package com.xc.entity.common;

/**
 * 文件上传进度信息
 */
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

springmvc-servlet.xml修改

<!-- 文件上传的配置 -->
<!-- <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> -->
<bean id="multipartResolver" class="com.xc.common.resolver.XcCommonsMultipartResolver">
    <property name="maxUploadSize" value="1048576" /><!-- 上传文件大小上限，单位为字节（1MB） -->
    <property name="defaultEncoding" value="UTF-8" /><!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
</bean>

参考文章：
Spring MVC 监听文件上传进度，实现上传进度条