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Apache Commons fileUpload实现文件上传

2016-03-20 00:11 645 查看

原文链接：http://zhangjunhd.blog.51cto.com/113473/18331/

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。

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

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left] <title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
//必须是multipart的表单数据。
[align=left] <form name="myform" action="demo1.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] Your name: <br>[/align]
[align=left] <input type="text" name="name" size="15"><br>[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
[align=left]</html>[/align]

demo1.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left] [/align]
[align=left]<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">[/align]
[align=left]<%[/align]
[align=left] boolean isMultipart = ServletFileUpload.isMultipartContent(request);//检查输入请求是否为multipart表单数据。[/align]
if (isMultipart == true)
{
[align=left] 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。[/align]
[align=left] ServletFileUpload upload = new ServletFileUpload(factory);[/align]
[align=left] List<FileItem> items = upload.parseRequest(request);[/align]
[align=left] Iterator<FileItem> itr = items.iterator();[/align]
[align=left] while (itr.hasNext()) {[/align]
[align=left] FileItem item = (FileItem) itr.next();[/align]
[align=left] //检查当前项目是普通表单项目还是上传文件。[/align]
[align=left] if (item.isFormField()) {//如果是普通表单项目，显示表单内容。[/align]
[align=left] String fieldName = item.getFieldName();[/align]
if (fieldName.equals("name")) //对应demo1.html中type="text"
name="name"
[align=left] out.print("the field name is" + item.getString());//显示表单内容。[/align]
[align=left] out.print("<br>");[/align]
[align=left] } else {//如果是上传文件，显示文件名。[/align]
[align=left] out.print("the upload file name is" + item.getName());[/align]
[align=left] out.print("<br>");[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] } else {[/align]
[align=left] out.print("the enctype must be multipart/form-data");[/align]
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left] <title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</html>

结果：

the field name isjeff

the upload file name isD:\C语言考试样题\作业题.rar

示例2
上传两个文件到指定的目录。
demo2.html

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left] <title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left] <form name="myform" action="demo2.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File1:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] File2:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
</html>

demo2.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left]<%@ page import="java.io.*"%>[/align]
[align=left] [/align]
[align=left]<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">[/align]
[align=left]<%String uploadPath="D:\\temp";[/align]
[align=left] boolean isMultipart = ServletFileUpload.isMultipartContent(request);[/align]
[align=left] if(isMultipart==true){[/align]
[align=left] try{[/align]
[align=left] FileItemFactory factory = new DiskFileItemFactory();[/align]
[align=left] ServletFileUpload upload = new ServletFileUpload(factory);[/align]
[align=left] List<FileItem> items = upload.parseRequest(request);//得到所有的文件[/align]
[align=left] Iterator<FileItem> itr = items.iterator();[/align]
[align=left] while(itr.hasNext()){//依次处理每个文件[/align]
[align=left] FileItem item=(FileItem)itr.next();[/align]
[align=left] String fileName=item.getName();//获得文件名，包括路径[/align]
[align=left] if(fileName!=null){[/align]
[align=left] File fullFile=new File(item.getName());[/align]
[align=left] File savedFile=new File(uploadPath,fullFile.getName());[/align]
[align=left] item.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] out.print("upload succeed");[/align]
[align=left] }[/align]
[align=left] catch(Exception e){[/align]
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] else{[/align]
[align=left] out.println("the enctype must be multipart/form-data");[/align]
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left]<title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</html>

结果：

upload succeed

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

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left] <title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left] <form name="myform" action="demo3.jsp" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
[align=left]</html>[/align]

demo3.jsp

<%@ page language="java" contentType="text/html;
charset=GB18030"
[align=left] pageEncoding="GB18030"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.servlet.*"%>[/align]
[align=left]<%@ page import="org.apache.commons.fileupload.disk.*"%>[/align]
[align=left]<%@ page import="java.util.*"%>[/align]
[align=left]<%@ page import="java.io.*"%>[/align]
[align=left] [/align]
[align=left]<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">[/align]
[align=left]<%[/align]
[align=left] File uploadPath = new File("D:\\temp");//上传文件目录[/align]
[align=left] if (!uploadPath.exists()) {[/align]
[align=left] uploadPath.mkdirs();[/align]
[align=left] }[/align]
[align=left] // 临时文件目录[/align]
[align=left] File tempPathFile = new File("d:\\temp\\buffer\\");[/align]
[align=left] if (!tempPathFile.exists()) {[/align]
[align=left] tempPathFile.mkdirs();[/align]
[align=left] }[/align]
[align=left] try {[/align]
[align=left] // Create a factory for disk-based file items[/align]
[align=left] DiskFileItemFactory factory = new DiskFileItemFactory();[/align]
[align=left] [/align]
[align=left] // Set factory constraints[/align]
[align=left] factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb[/align]
[align=left] factory.setRepository(tempPathFile);//设置缓冲区目录[/align]
[align=left] [/align]
[align=left] // Create a new file upload handler[/align]
[align=left] ServletFileUpload upload = new ServletFileUpload(factory);[/align]
[align=left] [/align]
[align=left] // Set overall request size constraint[/align]
[align=left] upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB[/align]
[align=left] [/align]
[align=left] List<FileItem> items = upload.parseRequest(request);//得到所有的文件[/align]
[align=left] Iterator<FileItem> i = items.iterator();[/align]
[align=left] while (i.hasNext()) {[/align]
[align=left] FileItem fi = (FileItem) i.next();[/align]
[align=left] String fileName = fi.getName();[/align]
if (fileName != null)
{
[align=left] File fullFile = new File(fi.getName());[/align]
[align=left] File savedFile = new File(uploadPath, fullFile[/align]
[align=left] .getName());[/align]
[align=left] fi.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] out.print("upload succeed");[/align]
[align=left] } catch (Exception e) {[/align]
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left]%>[/align]
[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left]<title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
[align=left]</body>[/align]
</html>

示例4
利用Servlet来实现文件上传。
Upload.java

[align=left]package com.zj.sample;[/align]
[align=left] [/align]
[align=left]import java.io.File;[/align]
[align=left]import java.io.IOException;[/align]
[align=left]import java.util.Iterator;[/align]
[align=left]import java.util.List;[/align]
[align=left] [/align]
[align=left]import javax.servlet.ServletException;[/align]
[align=left]import javax.servlet.http.HttpServlet;[/align]
[align=left]import javax.servlet.http.HttpServletRequest;[/align]
[align=left]import javax.servlet.http.HttpServletResponse;[/align]
[align=left] [/align]
[align=left]import org.apache.commons.fileupload.FileItem;[/align]
[align=left]import org.apache.commons.fileupload.disk.DiskFileItemFactory;[/align]
[align=left]import org.apache.commons.fileupload.servlet.ServletFileUpload;[/align]
[align=left] [/align]
[align=left]@SuppressWarnings("serial")[/align]
public class Upload extends HttpServlet
{
[align=left] private String uploadPath = "D:\\temp"; // 上传文件的目录[/align]
[align=left] private String tempPath = "d:\\temp\\buffer\\"; // 临时文件目录[/align]
[align=left] File tempPathFile;[/align]
[align=left] [/align]
[align=left] @SuppressWarnings("unchecked")[/align]
public void doPost(HttpServletRequest
request, HttpServletResponse response)
[align=left] throws IOException, ServletException {[/align]
[align=left] try {[/align]
[align=left] // Create a factory for disk-based file items[/align]
[align=left] DiskFileItemFactory factory = new DiskFileItemFactory();[/align]
[align=left] [/align]
[align=left] // Set factory constraints[/align]
[align=left] factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb[/align]
[align=left] factory.setRepository(tempPathFile);// 设置缓冲区目录[/align]
[align=left] [/align]
[align=left] // Create a new file upload handler[/align]
[align=left] ServletFileUpload upload = new ServletFileUpload(factory);[/align]
[align=left] [/align]
[align=left] // Set overall request size constraint[/align]
[align=left] upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB[/align]
[align=left] [/align]
[align=left] List<FileItem> items = upload.parseRequest(request);// 得到所有的文件[/align]
[align=left] Iterator<FileItem> i = items.iterator();[/align]
[align=left] while (i.hasNext()) {[/align]
[align=left] FileItem fi = (FileItem) i.next();[/align]
[align=left] String fileName = fi.getName();[/align]
if (fileName != null)
{
[align=left] File fullFile = new File(fi.getName());[/align]
File savedFile = new File(uploadPath,
fullFile.getName());
[align=left] fi.write(savedFile);[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] System.out.print("upload succeed");[/align]
[align=left] } catch (Exception e) {[/align]
[align=left] // 可以跳转出错页面[/align]
[align=left] e.printStackTrace();[/align]
[align=left] }[/align]
[align=left] }[/align]
[align=left] [/align]
public void init() throws ServletException
{
[align=left] File uploadFile = new File(uploadPath);[/align]
[align=left] if (!uploadFile.exists()) {[/align]
[align=left] uploadFile.mkdirs();[/align]
[align=left] }[/align]
[align=left] File tempPathFile = new File(tempPath);[/align]
[align=left] if (!tempPathFile.exists()) {[/align]
[align=left] tempPathFile.mkdirs();[/align]
[align=left] }[/align]
[align=left] }[/align]
}

demo4.html

[align=left]<html>[/align]
[align=left]<head>[/align]
<meta http-equiv="Content-Type" content="text/html;
charset=GB18030">
[align=left] <title>File upload</title>[/align]
[align=left]</head>[/align]
[align=left]<body>[/align]
// action="fileupload"对应web.xml中<servlet-mapping>中<url-pattern>的设置.
[align=left] <form name="myform" action="fileupload" method="post"[/align]
[align=left] enctype="multipart/form-data">[/align]
[align=left] File:<br>[/align]
[align=left] <input type="file" name="myfile"><br>[/align]
[align=left] <br>[/align]
[align=left] <input type="submit" name="submit" value="Commit">[/align]
[align=left] </form>[/align]
[align=left]</body>[/align]
</html>

web.xml

[align=left]<servlet>[/align]
[align=left] <servlet-name>Upload</servlet-name>[/align]
[align=left] <servlet-class>com.zj.sample.Upload</servlet-class>[/align]
[align=left]</servlet>[/align]
[align=left] [/align]
[align=left]<servlet-mapping>[/align]
[align=left] <servlet-name>Upload</servlet-name>[/align]
[align=left] <url-pattern>/fileupload</url-pattern>[/align]
</servlet-mapping>

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