Apache的commons-fileupload.jar可方便的实现文件的上传功能,本文通过实例来介绍如何使用commons-fileupload.jar。@author:ZJ 07-2-22Blog: [url]http://zhangjunhd.blog.51cto.com/[/url] 将Apache的commons-fileupload.jar放在应用程序的WEB-INF\lib下,即可使用。下面举例介绍如何使用它的文件上传功能。所使用的fileUpload版本为1.2,环境为Eclipse3.3+MyEclipse6.0。FileUpload 是基于 Commons IO的,所以在进入项目前先确定Commons IO的jar包(本文使用commons-io-1.3.2.jar)在WEB-INF\lib下。此文作示例工程可在文章最后的附件中下载。示例1最简单的例子,通过ServletFileUpload静态类来解析Request,工厂类FileItemFactory会对mulipart类的表单中的所有字段进行处理,不只是file字段。getName()得到文件名,getString()得到表单数据内容,isFormField()可判断是否为普通的表单项。demo1.html
<%@ page language="java" contentType="text/html; charset=GB18030"pageEncoding="GB18030"%><%@ page import="org.apache.commons.fileupload.*"%><%@ page import="org.apache.commons.fileupload.servlet.*"%><%@ page import="org.apache.commons.fileupload.disk.*"%><%@ page import="java.util.*"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><%boolean isMultipart = ServletFileUpload.isMultipartContent(request);//检查输入请求是否为multipart表单数据。if (isMultipart == true) {FileItemFactory factory = new DiskFileItemFactory();//为该请求创建一个DiskFileItemFactory对象,通过它来解析请求。执行解析后,所有的表单项目都保存在一个List中。ServletFileUpload upload = new ServletFileUpload(factory);List<FileItem> items = upload.parseRequest(request);Iterator<FileItem> itr = items.iterator();while (itr.hasNext()) {FileItem item = (FileItem) itr.next();//检查当前项目是普通表单项目还是上传文件。if (item.isFormField()) {//如果是普通表单项目,显示表单内容。String fieldName = item.getFieldName();if (fieldName.equals("name")) //对应demo1.html中type="text" name="name"out.print("the field name is" + item.getString());//显示表单内容。out.print("<br>");} else {//如果是上传文件,显示文件名。out.print("the upload file name is" + item.getName());out.print("<br>");}}} else {out.print("the enctype must be multipart/form-data");}%><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>File upload</title></head><body></body></html> |
结果:<html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>File upload</title></head><body><form name="myform" action="demo2.jsp" method="post"enctype="multipart/form-data">File1:<br><input type="file" name="myfile"><br>File2:<br><input type="file" name="myfile"><br><br><input type="submit" name="submit" value="Commit"></form></body></html> |
demo2.jsp此时,在"D:\temp"下可以看到你上传的两个文件。示例3上传一个文件到指定的目录,并限定文件大小。demo3.html<%@ page language="java" contentType="text/html; charset=GB18030"pageEncoding="GB18030"%><%@ page import="org.apache.commons.fileupload.*"%><%@ page import="org.apache.commons.fileupload.servlet.*"%><%@ page import="org.apache.commons.fileupload.disk.*"%><%@ page import="java.util.*"%><%@ page import="java.io.*"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><%File uploadPath = new File("D:\\temp");//上传文件目录if (!uploadPath.exists()) {uploadPath.mkdirs();}// 临时文件目录File tempPathFile = new File("d:\\temp\\buffer\\");if (!tempPathFile.exists()) {tempPathFile.mkdirs();}try {// Create a factory for disk-based file itemsDiskFileItemFactory factory = new DiskFileItemFactory();// Set factory constraintsfactory.setSizeThreshold(4096); // 设置缓冲区大小,这里是4kbfactory.setRepository(tempPathFile);//设置缓冲区目录// Create a new file upload handlerServletFileUpload upload = new ServletFileUpload(factory);// Set overall request size constraintupload.setSizeMax(4194304); // 设置最大文件尺寸,这里是4MBList<FileItem> items = upload.parseRequest(request);//得到所有的文件Iterator<FileItem> i = items.iterator();while (i.hasNext()) {FileItem fi = (FileItem) i.next();String fileName = fi.getName();if (fileName != null) {File fullFile = new File(fi.getName());File savedFile = new File(uploadPath, fullFile.getName());fi.write(savedFile);}}out.print("upload succeed");} catch (Exception e) {e.printStackTrace();}%><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>File upload</title></head><body></body></html> |
示例4利用Servlet来实现文件上传。Upload.java<html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>File upload</title></head><body>// action="fileupload"对应web.xml中<servlet-mapping>中<url-pattern>的设置.<form name="myform" action="fileupload" method="post"enctype="multipart/form-data">File:<br><input type="file" name="myfile"><br><br><input type="submit" name="submit" value="Commit"></form></body></html> |
web.xml<td 230,="" 230)="" none="" repeat="" scroll="" 0%="" 50%;="" width:="" 568px;="" -moz-background-clip:="" -moz-initial;="" -moz-background-origin:="" -moz-background-inline-policy:="" -moz-initial;"="" valign="top" width="568" style="padding: 0 7px;border-width: 1px;border-color: windowtext">
<servlet><servlet-name>Upload</servlet-name><servlet-class>com.zj.sample.Upload</servlet-class></servlet><servlet-mapping><servlet-name>Upload</servlet-name><url-pattern>/fileupload</url-pattern></servlet-mapping>
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