WEB文件上传之apache common upload使用（一）

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文件上传

文件上传一个经常用到的功能，它有许多中实现的方案。

页面表单 + RFC1897规范 + http协议上传

页面控件(flash/html5/activeX/applet) + RFC1897规范 + http协议上传

页面控件(flash/html5/activeX/applet) + 自定义数据规范 + http协议上传

页面控件(flash/html5/activeX/applet) + FTP协议上传

页面控件(flash/html5/activeX/applet) + 自定义协议

用apache common upload组件实际就是采用的“页面表单 + RFC1897规范 + http协议上传”实现方式，需要实现的技术点：

1. 多文件数据的提交

2. 文件数据包接收存储功能

3. 文件数据上传进度

4. WEB页面无刷新异步提交

时序图：

文件上传时序图

文件上传进度获取时序图

实现思路：

1. 多文件数据的提交

在WEB页面采用多个<input type="file">利用form表单进行文件提交

2. 文件数据包接收存储功能

服务端采用servlet，利用apache common upload组件接收解析数据包，接收解析的过程中保存进度到session, 文件接收完毕后保存到指定目录

3. 文件数据上传进度

在WEB页面在界面写一个定时器，定时访问服务器提供上传进度获取功能的servlet，获取文件上传进度信息

4. WEB页面无刷新异步提交

利用iframe来实现WEB页面无刷新异步上传

关键代码：

UploadFileServlet.java

package com.test.servlet;

import java.io.File;
import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.FileCleanerCleanup;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileCleaningTracker;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 文件上传数据接收类
 * 
 * @author chengqi
 *
 */
public class UploadFileServlet extends HttpServlet {

	/** 日志对象*/
	private Log logger = LogFactory.getLog(this.getClass());

	private static final long serialVersionUID = 1L;

	/** 上传目录名*/
	private static final String uploadFolderName = "uploadFiles";

	/** 上传临时文件存储目录*/
	private static final String tempFolderName = "tempFiles";

	/** 上传文件最大为30M*/ 
	private static final Long fileMaxSize = 30000000L; 

	/** 允许上传的扩展名*/
	private static final String [] extensionPermit = {"txt", "xls", "zip"};

	/** 统一的编码格式*/
	private static final String encode = "UTF-8";

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		logger.info("UploadFileServlet#doPost() start");
		try {
			String curProjectPath = this.getServletContext().getRealPath("/");
			String saveDirectoryPath = curProjectPath + "/" + uploadFolderName;
			String tempDirectoryPath = curProjectPath + "/" + tempFolderName;
			File saveDirectory = new File(saveDirectoryPath);
			File tempDirectory = new File(tempDirectoryPath);
			logger.debug("Project real path [" + saveDirectory.getAbsolutePath() + "]");
			//上传时产生的临时文件的默认保存目录
			logger.debug("Temp files default save path [" + System.getProperty("java.io.tmpdir") + "]");
			DiskFileItemFactory factory = new DiskFileItemFactory();
			//DiskFileItemFactory中DEFAULT_SIZE_THRESHOLD=10240表示如果上传文件大于10K则会产生上传临时文件
			//上传临时文件的默认目录为java.io.tmpdir中保存的路径，根据操作系统的不同会有区别
			
			if(!tempDirectory.exists()) {
				tempDirectory.mkdir();
			}
			//重新设置临时文件保存目录
			factory.setRepository(tempDirectory);

			//设置文件清除追踪器，文件上传过程中产生的临时文件会在
			FileCleaningTracker fileCleaningTracker = FileCleanerCleanup.getFileCleaningTracker(this.getServletContext());
			factory.setFileCleaningTracker(fileCleaningTracker);

			ServletFileUpload upload = new ServletFileUpload(factory);

			//设置文件上传进度监听器
			FileProcessListener processListener = new FileProcessListener(request.getSession());
			upload.setProgressListener(processListener);

			// 设置文件上传的大小限制
			upload.setFileSizeMax(fileMaxSize);

			// 设置文件上传的头编码，如果需要正确接收中文文件路径或者文件名
			// 这里需要设置对应的字符编码，为了通用这里设置为UTF-8
			upload.setHeaderEncoding(encode);

			//解析请求数据包
			List<FileItem> fileItems = upload.parseRequest(request);
			//遍历解析完成后的Form数据和上传文件数据
			for (Iterator<FileItem> iterator = fileItems.iterator(); iterator.hasNext();) {
				FileItem fileItem = iterator.next();
				String fieldName = fileItem.getFieldName();
				String name = fileItem.getName();
				//如果为上传文件数据
				if(!fileItem.isFormField()) {
					logger.debug("fieldName[" + fieldName + "] fileName[" + name + "] ");
					if(fileItem.getSize() > 0) {
						String fileExtension = FilenameUtils.getExtension(name);
						if(!ArrayUtils.contains(extensionPermit, fileExtension)) {
							throw new NoSupportExtensionException("No Support extension.");
						}
						String fileName = FilenameUtils.getName(name);
						FileUtils.copyInputStreamToFile(fileItem.getInputStream(), 
								new File(saveDirectory, fileName));
					}
				} else { //Form表单数据
					String value = fileItem.getString(encode);
					logger.debug("fieldName[" + value + "] fieldValue[" + fieldName + "]");
				}
			}
			responseMessage(response, State.OK);
		} catch(FileSizeLimitExceededException e) { 
			logger.error(e.getMessage(), e);
			responseMessage(response, State.OVER_FILE_LIMIT);
		} catch(NoSupportExtensionException e) { 
			logger.error(e.getMessage(), e);
			responseMessage(response, State.NO_SUPPORT_EXTENSION);
		} catch(Exception e) {
			logger.error(e.getMessage(), e);
			responseMessage(response, State.ERROR);
		} finally {
			//清除上传进度信息
			request.getSession().removeAttribute("fileUploadProcess");
		}
		logger.info("UploadFileServlet#doPost() end"); 
	}

	public enum State {
		OK(200, "上传成功"),
		ERROR(500, "上传失败"),
		OVER_FILE_LIMIT(501, "超过上传大小限制"),
		NO_SUPPORT_EXTENSION(502, "不支持的扩展名");

		private int code;
		private String message;
		private State(int code, String message) {
			this.code = code;
			this.message = message;
		}

		public int getCode() {
			return code;
		}
		public String getMessage() {
			return message;
		}

	}

	/**
	 * 返回结果函数
	 * @param response
	 * @param state
	 */
	private void responseMessage(HttpServletResponse response, State state) {
		response.setCharacterEncoding(encode);
		response.setContentType("text/html; charset=" + encode);
		Writer writer = null;
		try {
			writer = response.getWriter();
			writer.write("<script>");
			writer.write("window.parent.fileUploadCallBack({\"code\":" + state.getCode() +",\"message\":\"" + state.getMessage()+ "\"});");
			writer.write("</script>");
			writer.flush();
			writer.close();
		} catch(Exception e) {
			logger.error(e.getMessage(), e);
		} finally {
			IOUtils.closeQuietly(writer);
		}
	}


}

GetFileProcessServlet.java

package com.test.servlet;

import java.io.IOException;
import java.io.Writer;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 文件上传进度获取Servlet
 * 
 * @author chengqi
 *
 */
public class GetFileProcessServlet extends HttpServlet {

	/** 日志对象*/
	private Log logger = LogFactory.getLog(this.getClass());

	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		logger.info("GetFileProcessServlet#doGet start");
		String fileUploadPercent = (String)request.getSession().getAttribute("fileUploadProcess");
		Writer writer = null;
		try {
			writer = response.getWriter();
			logger.info("percent:" + fileUploadPercent);
			IOUtils.write(fileUploadPercent == null ? "0%" : fileUploadPercent, writer);
			writer.flush();
			writer.close();
		} catch(Exception e) {
			logger.error(e.getMessage(), e);
		} finally {
			IOUtils.closeQuietly(writer);
		}
		logger.info("GetFileProcessServlet#doGet end");
	}

}

FileProcessListener.java

package com.test.servlet;

import java.text.NumberFormat;

import javax.servlet.http.HttpSession;

import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 文件进度监听器
 * 
 * @author chengqi
 *
 */
public class FileProcessListener implements ProgressListener{

	/** 日志对象*/
	private Log logger = LogFactory.getLog(this.getClass());

	private HttpSession session;

	public FileProcessListener(HttpSession session) {
		this.session = session;  
	}
	

	public void update(long pBytesRead, long pContentLength, int pItems) {
		double readByte = pBytesRead;
		double totalSize = pContentLength;
		if(pContentLength == -1) {
			logger.debug("item index[" + pItems + "] " + pBytesRead + " bytes have been read.");
		} else {
			logger.debug("item index[" + pItems + "] " + pBytesRead + " of " + pContentLength + " bytes have been read.");
			String p = NumberFormat.getPercentInstance().format(readByte / totalSize);
			session.setAttribute("fileUploadProcess", p);
		}
	}

}

apacheUploadDemo.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
	<title>Apache common实现基本文件上传</title>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
	<script type="text/javascript" src="js/jquery/jquery-1.9.1.js"></script>
	<script type="text/javascript" src="js/jquery/jquery.form.js"></script>
	<script type="text/javascript">

	//定时器对象
	var uploadProcessTimer = null;

	$(function (){
		//绑定定时器开始操作到提交按钮
		$('input[type=submit]').click(function () {
			//启动上传进度查询定时器
			uploadProcessTimer = window.setInterval(getFileUploadProcess, 20);
		})
	});

	//获取文件上传进度
	function getFileUploadProcess() {
		$.get('/upload/getFileProcessServlet', function(data) {
			$('#fileUploadProcess').html(data);
		});
	}

	//上传完成后，由iframe返回脚本自动调用
	function fileUploadCallBack(res) {
		//清除定时器
		if(uploadProcessTimer) {
			window.clearInterval(uploadProcessTimer);
		}
		var message = res['message'];
		var code = res['code'];
		if(code != 200) {
			$('#fileUploadProcess').html('0%');
		}
		alert(message);
	}

	</script>
</head>
<body>
<h2>上传文件1</h2>

用户信息：  <br/>
<form id="testForm" action="/upload/uploadServlet" method="post" enctype="multipart/form-data" target="iframeUpload">
	姓名：<input name="name" type="text"> <br/>
	附件1：<input name="file1" type="file" > <br/>
	附件2：<input name="file2" type="file" > <br/>
	<br><br>
	<input type="submit" value="提交" ><br/>
</form>
上传进度：<label id="fileUploadProcess"></label>
<iframe name="iframeUpload" src="" width="350" height="35" frameborder=0  SCROLLING="no" style="display:NONE"></iframe>   
</body>
</html>

总结：

虽然使用apache common upload组件实现了文件上传，但是从上传的效果来看，并不是一个很完美的解决方案。

有如下缺点：

1. 当有多个文件上传时，无法知道单个文件的上传进度，因为文件上传消息中根本就没有关于单个文件大小的信息

文件上传消息

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Content-Type: text/html;charset=UTF-8
Transfer-Encoding: chunked
Date: Tue, 22 Apr 2014 07:45:45 GMT

POST /upload/uploadServlet HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Referer: http://localhost:8080/upload/apacheUploadDemo.html
Cookie: JSESSIONID=33498CE814284D67F957CA53D45F0174
Connection: keep-alive

Content-Length 2363
Content-Type multipart/form-data; boundary=---------------------------189163093917262

-----------------------------189163093917262
Content-Disposition: form-data; name="name"

-----------------------------189163093917262
Content-Disposition: form-data; name="file1"; filename="New Text Document.txt" Content-Type: text/plain
文件数据

-----------------------------189163093917262
Content-Disposition: form-data; name="file2"; filename="New Text Document (2).txt" Content-Type: text/plain
文件数据

-----------------------------189163093917262--

2. 浏览器必须将所有文件读取完毕才开始上传，并且是一次性提交所有的数据文件，在互联网环境下，会http连接超时，大文件无法上传成功。

3. 服务端判断是否超过大小限制，是通过计算接收数据的累积字节数和限制大小比较，这种情况下，如果限制大小是30M，那么在服务端已经读取了30M完成后才会抛出异常，多余的消耗的服务器的内存和硬盘空间

所以基于这些原因，页面表单 + RFC1897规范 + http协议上传 + 后台apache common upload组件接收的这种解决方案，不适合解决WEB页面一次多文件上传，大文件上传情况，比较适合一次单个小文件附件的情况，如：博客附件，登记照片上传，预览等情况。

Demo源码见附件